aft presentation in india

AFT Products

Reinaldo Pinto Global Sales Manager

..\Brand Video Compressed\AFT Brand Video 35MB FINAL.mp4

Agenda

About Applied Flow Technology

Office and Worldwide Distributors

Product Applications

AFT Software List

Pipe Network Design Challenges

Pipe Network Design Challenges and AFT products

Customers

Overview of AFT Software

Fathom

Fathom Examples

Impulse

Impulse Examples

Arrow

Arrow Examples


Applied Flow Technology (AFT) is an international software development and consulting company

Founded in 1993, AFT has rapidly grown to be a leader in the pipe flow modeling software market

Primary business focus is developing high quality fluid flow analysis products for Microsoft Windows

AFT Office and Worldwide Distributors

Representatives in 32 countries

Customers in 70+ countries

AFT products are being successfully applied to a broad range of industrial systems: Power generation systems Chemical and petrochemical systems Oil and gas production, transportation, refining and delivery Marine and offshore Automotive systems Aerospace systems Air conditioning and refrigeration systems Semi-conductor manufacturing systems Pulp and paper processing Fire suppression Water and Wastewater treatment plant design Mining processing and support systems Biomedical products and pharmaceutical processing Municipal water distribution

September 20, 2012 6

Product Applications

Incompressible pipe network analysis

AFT Fathom 8 AFT Fathom Add-On Modules

XTS - eXtended Time Simulation GSC - Goal Seek & Control SSL Settling Slurry simulation

According to Hatch Mott McDonald, there are many benefits of using AFT Fathom software.

AFT Fathom is, above all, reliable software. This is crucial to Hatch Mott MacDonald, a company whose reputation depends on the reliability of the final product. It is robust, and forthcoming with its calculation approaches.

AFT Fathom 8.0 Viewer (No Cost) AFT Mercury 7.0

7


Compressible flow pipe network analysis AFT Arrow 5.0

In commenting on the benefits achieved by modeling this complex system with AFT Arrow, Mr. Klepacki said;

Using AFT Arrow I could check all parameters and find the optimal dimensions of conduits in order to deliver the required flow through the FGD plants. Another very important aspect is when we are to introduce changes. (in my case I have calculated about 40 scenarios so it has brought me a really great benefit).

AFT Arrow Add-On Modules GSC - Goal Seek & Control

AFT Arrow 5.0 Viewer (No Cost)

AFT Titan 4.0

8


Overview of AFT Software (Cont.)

Transient Analysis

AFT Impulse 5.0

According to Chicago Bridge Iron about Impulse:

AFT Impulse allowed the separation of "reality" from "theoretical" to arrive at a true model of the existing system

AFT Impulse 5.0 Viewer (No Cost)

Chempak Property Database Property database of ~700 fluids Ability to define static pre-mixtures Dynamic mixing capability in Arrow

9

Overview of AFT Software (Cont.)

AFT Academic Program

Licenses for Research and Development

Licenses for Hydraulic Courses

AFT Flow Expert Package (New)

AFT Flow Expert Packages provide consulting services

beyond typical technical support requests on the installation,

upgrade assistance, and functionality of AFT software

Package Options

5 Hours

10 Hours

20 Hours

10


1. Meeting design parameters Specs.: Pressure, Flow, Temperature, Energy Consumption, etc. 2. Dealing with Hydraulic Phenomena's:

1. Cavitation (steady state and transient)

Valves erosion Pumps erosion Valves leak Pipe Collapse ..\..\Seminar\Technical Topics\Collapse\Railroad tank car vacuum implosion.avi Pipe flashing (vapor cavities)

2. Overpressures

Pipe Rupture ..\..\Seminar\Technical Topics\Pipe failure - pump start-up\Sea Water Pump Explosion _ Video _ Break.com_2.mp4

Pipe Support Failure Waterhammer Videos\How a Bladder Surge Tank can alleviate column separation1.wmv ;

In the construction of pump storage installation the greatest concern must be given to the question of operational safety right from the beginning. For this reason exhaustive and accurate data on the pressure fluctuations caused when the pump motors cut out suddenly must be worked out in the project stage. Only this way suitable precautions be taken in good time to prevent inadmissible pressures M. Marchal, G. Flesh and P. Suter

Article: The calculation of Waterhammer problems by means of the digit computer

System Protection devices Failure to Control: Relief Systems, Equipment Protection devices, etc. Relief Valve Cycling (Chattering) ..\..\Seminar\Technical Topics\Valve Chattering\Safety Valve -

Chattering.avi

3. Sonic Choking Flow limitation

3. Code Compliance

11

Pipe Network Design Challenges and AFT

products

AFT products will not only allow you to deal with all the Pipe Network Design Challenges , also they will give you access to powerful designing tools that will make your design more easy, comprehensive and facilitates finding a solution to any problem. Among these tools we can mention:

Scenario Manager to track all design variants and operational possibilities in a single model file.

Detailed modeling for centrifugal and positive displacement pumps Thermal analysis including piping heat transfer and heat exchanger

modeling

Pump vs. system curve generation including individual head curves and composite efficiency

Select pumps from online manufacturer catalogs Specify alerts that automatically highlight output values that are out of

range for flow, pressure or velocity

Built-in library of fluids and fittings Supports Newtonian and non-Newtonian fluids, including non-settling

and settling slurries

12

Customers

13

Customers in India

14

AFT Fathom 8 Overview

Models incompressible network pipe systems Liquid and low velocity gas systems

Implements highly advanced Microsoft Windows graphical interface Users give Fathom high marks for ease of use

Models open and closed systems Models systems that are pressure, gravity or pump driven Models heat transfer and system energy balance Offers broad range of innovative reporting features

Printed output is of report quality

Offers customizable component and property databases Cost calculations

Rheological data handling to support non-Newtonian fluids

Modules for: Extended Time Simulation Goal Seek & Control Settling Slurries

15

AFT Fathom Add-On Module Overview

XTS Simulate dynamic behavior of systems over time

Models infinite and open and closed finite tanks of constant and varying cross section

Supports user defined time and event transients of pumps, valves and other components

GSC Automatically determines input variables that will yield specified

output values

Extends Fathoms control simulation capabilities to include remote sensing

SSL Simulates settling slurry behavior

Simulates pump performance degradation

16

AFT Impulse 5.0 Overview

Models Transient flow in pipe networks Implements highly advanced Microsoft Windows graphical interface Models system transients caused by

Sudden valve closures Pump startups and shutdowns including pump inertia effects Relief valve cracking Events defined within the system (e.g. flow, pressure, etc.)

Includes modeling of Control and relief valves Pumps Accumulators & surge tanks Vacuum relief valves

Models open and closed systems Includes a steady-state solver to determine initial conditions

Can also import AFT Fathom models

Calculates unbalanced transient forces Forces can be graphed or exported as Force/Time data files

17

Mercury 7.0 Overview

Allows: Analysis, design and optimization of incompressible network pipe systems

Combines a powerful hydraulic solver and flexible graphical interface with an advanced optimization engine

Automatically selects optimal pipe and component sizes to minimize initial or life cycle cost, size or weight

Ability to apply multiple constraints to pipes and junctions

Cost optimization may include; non-recurring costs (materials and installation)

recurring costs (energy and maintenance) including time varying cost (energy costs varying with time)

Offers customizable engineering and cost databases

Includes powerful modeling and output capabilities of AFT Fathom 7.0

September 20, 2012 18

Arrow 5.0 Overview

Models compressible network pipe systems

High to low velocity gas systems High to low pressures

Implements highly advanced graphical interface very similar to Fathom

Models open and closed systems Accurately models

Real gases Heat transfer Highly compressible (sonic and near sonic) systems

Offers broad range of innovative reporting features Balances flow and energy throughout the system Offers customizable component and property databases Includes high accuracy steam/water properties to ASME Modules for:

Goal Seek & Control Cost calculations

19

Arrow Add-On Module Overview

GSC

Automatically determines input variables that will yield specified output values

Extends Arrows control simulation capabilities to include remote sensing

CST

Supports cost databases for piping, fittings, valves, pumps and other system components

Analyzes first and life cycle cost of piping/pump systems

Integrates system hydraulic design and cost

20

Titan 5.0 Overview

Allows: Analysis, design and optimization of compressible network pipe systems

Combines a powerful hydraulic solver and flexible graphical interface with an advanced optimization engine

Automatically selects optimal pipe and component sizes to minimize initial or life cycle cost, size or weight

Ability to apply multiple constraints to pipes and junctions

Cost optimization may include; non-recurring costs (materials and installation)

recurring costs (energy and maintenance) including time varying cost (energy costs varying with time)

Offers customizable engineering and cost databases

Includes powerful modeling and output capabilities of AFT Arrow 4.0

21

AFT FATHOM

Modelaje de Flujo Incompresible

22

General purpose pipe network incompressible flow analysis

Advanced drag-and-drop interface

Calculates pressure drop, flow distribution and (optionally) energy balance in pipe networks

Implements Newton-Raphson matrix techniques to solve 3 equations:

Continuity (Mass) Equation

Momentum (Bernoulli) Equation

Energy Equation (optional)

23

AFT Fathom General Description

AFT Fathom -

Can model systems in any generalized configuration

Open or closed systems

Branching systems

Looping systems

Can model any fluid in which the viscosity is Newtonian

Can model non-Newtonian fluids using Power Law and Bingham Plastic

Can model variable fluid properties

English and SI units supported

24

AFT Fathom General Description (cont.)

AFT Fathom -

Branching section (up to 25 pipes)

Known pressure or flow boundaries

Pumps

Pump curves follow a polynomial equation or can be linearly interpolated

Centrifugal pumps and positive displacement pumps

Pressure and flow control valves

Relief valves and check valves

Spray discharge nozzles, sprinklers.

Heat Exchangers

Tanks

25

Components That Can Be Modeled

AFT Fathom -

Heat exchangers

Hydraulic losses

Heat transfer

General fittings and components where the resistance curve follows a polynomial relationship

Also can be modeled as linearly interpolated data

Piping insulation

26

Components That Can Be Modeled (cont.)

AFT Fathom -

AFT Fathom uses the Newton-Raphson Method to solve the flow distribution in a pipe network

The Newton-Raphson Method for pipe networks is a matrix method

This method gained favor with the introduction of the digital computer

The technique has been considered standard industry practice for 40 years

27

Solution Techniques

AFT Fathom -

Mass Conservation

=

Momentum Equation (Bernoulli)

1 +1

21

2 + 1 = 2 +1

22

2 + 2 +

The dynamic pressure and static pressure can be combined into the stagnation (total) pressure, and the solution is then for

total pressure

Therefore, the momentum equation becomes

,1 + 1 = ,2 + 2 +

28

Basic Laws of Pipe Flow

AFT Fathom -

Traditional method of friction loss calculation uses the Darcy-Weisbach friction factor, f

=

1

22

The friction factor is not a constant, but a function of the pipe wall characteristics and the Reynolds number

AFT Fathom uses the iterative Colebrook-White correlation for turbulent flow and the traditional laminar flow equation

= 1.14 2 log

+

9.35

2

(Re > 4000)

=64

(Re < 2300)

29

Law of Friction

AFT Fathom -

AFT FATHOM

EXAMPLES

Modelaje de Flujo Incompresible

30

Determine the pump head and power for the following system

Water system at 21 degrees C

Reservoir at 3 meters elevation needs to be pumped up a hill to a reservoir at 60 meters elevation

Flow requirement is 110 m3/hr

The total pipe length is 300 meters

The pipe is 4 inch (10.23 cm ID) Schedule 40 Steel

Pump efficiency = 80%

31

Model 1: Pump Sizing

5m

295m

3m

3m

60m

AFT Fathom -

32

Model 1: Pump Sizing - Layout

AFT Fathom -

33

Model 1: Pump Sizing - Output

Note: Pump Head Rise = 93.4 m

This has 2 parts: Elevation Rise = 57.0 m Frictional Head = 36.4 m

AFT Fathom -

34

Model 1: Pump Sizing Select a Pump

Choose a pump with adequate head rise at the design flow Q dH (m3/h) (m) 0 102 110 94 220 56

AFT Fathom -

35

Model 1: Pump Sizing Enter Pump Data

AFT Fathom -

36

Model 1: Pump Sizing Fit Curve to Data

AFT Fathom -

37

Model 1: Pump Sizing Review Selected Pump

AFT Fathom -

38

Model 1: Pump Sizing Create Pump System Curve

AFT Fathom -

39

Model 1- Pump Sizing System Curve H

ead

Flowrate

Total Dynamic Head (TDH)

Friction

Pump Curve

System Curve

Operating Flow Rate

Static

Hs

Hf

93.9m

57.0m

36.9m

110.7 m3/hr

AFT Fathom -

After selecting and buying the pump in Example #1, it is determined the velocity is too high

A variable speed drive is proposed to reduce the flow rate from 110 to 90 m3/hr

What is the new efficiency and power usage?

What speed will the pump operate?

40

Model 2: Variable Speed Pumping

5m

295m

3m

3m

60m

AFT Fathom -

41

Model 2: Variable Speed Pump Enter Setpoint

AFT Fathom -

42

Model 2: Variable Speed Pump Output

AFT Fathom -

43

Model 2: Variable Speed Pump New Head Rise


This has 2 parts: Elevation Rise = 57.0 m Frictional Head = 24.7 m

AFT Fathom -

44

Model 2: Variable Speed Pump Pump System Curve

Head

Flowrate

Pump Curve (No Control) System Curve

No Control

VFD VFD

Hs

Hf

Hs

Hf

No Control

Pump Curve (VFD at 92.1% Speed) 93.9m

57.0m

36.9m

110.7 m3/hr

81.7m

24.7m

90 m3/hr

57.0m

AFT Fathom -

After selecting and buying the pump in Example #1, it is determined the velocity is too high

Use a flow control valve to reduce the flow rate from 110 to 90 m3/hr

What is the new efficiency and power usage?

What speed will the pump operate?

45

Model 3: Flow Control Valve Evaluation

5m

295m

3m

3m

60m

AFT Fathom -

Use SHIFT key and then drag a Control Valve junction onto P2

This is the Split Pipe feature

March 14-15, 2013 46

Model 3: Flow Control Valve Add Valve

AFT Fathom -

47

Model 3: Flow Control Valve Enter Setpoint

AFT Fathom -

48

Model 3: Flow Control Valve Output

This has 3 parts: Elevation Rise = 57.0 m Frictional Head = 24.7 m Head Loss Across Control Valve = 16.0 m (shown on Valve Summary tab)


AFT Fathom -

49

Model 3: Flow Control Valve Pump System Curve

Head

Flowrate

Pump Curve

System Curve

Hs

Hf

Hs

Hf

Hcv

With Valve

Without Valve

Head Loss Across Control Valve

93.9m

57.0m

36.9m

97.7m

57.0m

16.0m

24.7m

110.7 m3/hr 90 m3/hr

AFT Fathom -

Modeling and Selecting Pumps

Pumps

Pumps can be modeled with pump curves, fixed flows or fixed pressure/head rise

Pump curves introduce a strong non-linearity into the model

Multiple pumps in parallel frequently require lower flow rate relaxation values

The pump pressure/head is listed in the General Results section of the output

Using undersized or oversized pumps can lead to modeling results that do not reflect reality

In the case of an undersized pump with hydrostatic head greater than shut off, Fathom will model backflow with the pump at shut off head

where, in reality, the pump head will be different

An oversized pump may be at runout, which is not modeled (Fathom extrapolates based on the curve fit - you can specify an end of curve

flow rate so Fathom will warn you if the solution is beyond the rate of

flow)

Pumps

Variable speed pumps can be modeled by entering the pump speed

Pump runout can be indentified

Viscosity corrections using Hydraulics Institute Standard can be applied

Control to a flow rate, suction or discharge pressure can be performed

Variable NPSH curves can be entered

Efficiency/power data can be entered

Fathom will determine power usage and proximity to BEP

Working with Pump Data and Results

Pump data can be entered

for the head curve, NPSH

and efficiency. Data is

input in the Pump

Configuration window.

The Pump Summary is

included in the General

Results of the Output

window

Pump Summary

The Pump Summary report in the output window gathers all pump data into one location for convenient review

Pump head and pressure rise

Pump horsepower - ideal if no efficiency curve data is provided or brake horsepower if efficiency curve is provided

Pump speed

NPSHA and NPSHR

BEP and percent of BEP (if efficiency or power data is entered)

Viscosity correction constants CQ and CH (only if viscosity corrections are used)

This report is displayed by selection within the General Output tab of the Output Control window then accessed using the Pump Summary tab of the Output window.

Variable Speed Pumps

If a speed other than 100% is entered for a pump, AFT Fathom will modify the pump curve according to the pump

affinity laws

Head ratio is related to speed ratio by square law

Flow ratio is related to speed ratio linearly

D

D

H

H

n

n

1

2

1

2

2

=

Q

Q

n

n

1

2

1

2

=

D

D D

D

D

H a bQ cQ dQ eQ

H s H s a s s cQ s dQ s eQ

H s a s

Q

s c s

s d s e Q

s

H s a sbQ cQ d Q

s e

Q

s

1 1 1 2

1 3

1 4

2 2

1 2 2

1 2

1 2 2

1 3 2

1

4

2 2 2 2

3 2 2

4

2 2

2 2 2 2

3 3 2

4

= + + +

= = + + +

= +

+

+

= + + + +

Variable Speed Pumps (cont.)

For several speed ratios the pump curves look as follows:

0

5

10

15

20

0 50 100 150 200

Flow Rate (gpm)

Head

(ft)

100%

80%

60%

Variable Speed Pumps (cont.)

For variable speed pumps Fathom can calculate the speed required to deliver a specified discharge pressure/head or flow

You cannot simultaneously input the speed because that is what is being calculated

Fathom disables the speed input field

The required speed is display in the Pump Summary of the Output window

Variable Speed Pumps Example

Open "Variable Speed Pumps.fth" from disk (or "Variable Speed Pumps (SI).fth for metric) Models\Fathom Models\Variable Speed Pumps (SI)(complete).fth

Create a new scenario and make it current.

Set pump J7 to Controlled Pump (Variable Speed) 400 gpm / 100 m3/hr

How do the pump flows compare to the Base Scenario?

Create a new scenario below the scenario created above

Set pump J4 to 90% speed

How do the pump flow compare to the previous scenario? Why?

Cavitation and NPSH

AFT Fathom will calculate local static pressures for the purpose of identifying cavitation

The vapor pressure of the fluid must be entered into System Properties

The Restricted Area must be input for the junction so AFT Fathom can perform the local pressure calculation

AFT Fathom does not model cavitation - rather, it identifies where it occurs in the system

If NPSH data is entered for a pump, AFT Fathom will check the required NPSH (i.e., NPSHR) vs. that which is available

(i.e., NPSHA)

NPSHA and NPSHR are displayed in the Pump Summary

AFT Fathom models variable NPSH curves

Pump Configurations

Pump data can be entered for multiple configurations

The default is a single configuration.

A pump configuration is a pump with a specific impeller trim and operating speed

Multiple impeller trims and operating speeds can be specified as part of the pump, then a particular combination can be chosen

Data for NPSH and Efficiency (or Power) is optional

These parameters do not affect the solution

They are used only for diagnostics

With Efficiency/Power data, Fathom determines the Best Efficiency Point (BEP) and the proximity of the operating point to BEP

Pump Configurations (cont.)

The Pump Configuration window is opened from the Pump Properties window

Click the Create button to input a new configuration

Pump Configurations (cont.)

Multiple configurations are displayed on the Pump Properties window in dropdown lists for selection

Pump Configurations Reference Density

Pump curves in terms of head and volumetric flow rate DO NOT change with density

Curves in terms of pressure or mass flow rate ARE dependent on density

Power curves DO change with density

Pump Configurations Reference Density

A reference density can be entered so the difference between the system properties fluid density and the pump test fluid

(reference density) will always be accounted for

Pump Impeller Modifications

Users can input impeller modifications

Pumps curves (and NPSH and efficiency/power curves) will be automatically adjusted

Impeller modification can be of two types:

Ratio from a single curve

Entered as percent

Interpolation between two curves

Entered as absolute diameter

Pump Impeller Modifications (cont.)

Entering "Ratio as Percent" will use affinity laws for impellers to adjust the selected pump curve data

This feature is available whenever a pump curve is entered

Pump Impeller Modifications (cont.)

Entering "Actual Impeller Trim" will interpolate between the closest impeller data

Affinity laws are used in the interpolation

This feature only available with multiple configurations

Pump Impeller Information in Output

Pump Summary in Output window can show impeller information

One Pump Can Represent Multiple Pumps

A single pump can represent multiple identical pumps in parallel or series

Control Valves

Control Valves

AFT Fathom has four types of control valves

Flow Control

Pressure reducing (control on downstream of valve)

Pressure sustaining (control on upstream of valve)

Pressure drop control (same pressure drop always)

Control Valve junctions can be used to model actual control valves or to size regular valves

Required pressure drop will be identified

FCV's, PRV's a PSV's will take as much pressure drop as is required to control to desired conditions

The Valve Summary in Output window shows Cv and all relevant data for Control Valves grouped together

Supply Tank Pump Tee (Simple) Elbow (Standard)

FCV FCV

Receiver Tank

Valve (Lossless)

Pumped System with FCVs

Size pump with flow control valves (TEST7 (SI).FTH / Test 7)

Supply tank liquid elevation is 1.5 meters, with 0.7 barG (70 kPa-g) surface pressure

Receiving tank liquid elevation is at 3 meters, with 2.1 barG (210 kPa-g) surface pressure

Specify pump as Volumetric Fixed Flow at 50 m3/hr

System fluid: Water @ 21 C

All pipes are:

Steel - ANSI, 2 inch (5.25 cm ID), schedule 40

6 meters long

All non-reservoir junctions are on the ground at 0 meters elevation

Two flow control valves in parallel require 25 m3/hr each with a minimum of 0.3 bar (30 kPa) drop

System looks as below:

Pump

(modeled as fixed

flow)

Tee (Simple)

Elbow (Standard)

FCV FCV

Valve (Lossless)

Pumped System with FCVs (cont.)

When you try to run this model the reference pressure error is displayed The error message identifies the following junctions as lacking a reference

pressure -

This represents the following portion of the system, which is bounded by

fixed flows - the fixed flow pump and the two flow control valves


This is analogous to a single pipe with specified flow, Q, at the inlet and outlet -

This situation cannot be solved because there is no unique solution You could calculate the pressure drop along this pipe, but not the pressure since

a deltaP can be the difference between an infinite number of possible Pinlet and Poutlet values

This is not merely a matter of mathematics, but is an issue with real systems and is why, for example, closed loop systems have expansion or head tanks

The solution to this modeling dilemma is to make one of the FCVs a PDCV PDCV setting is the minimum deltaP needed across the control valve To insure all control valves have at least the minimum deltaP, the hydraulically

most distant FCV is selected to be changed to a PDCV

Note that the GSC module offers a direct way of solving this issue without resorting to the PDCV (see GSC Example scenario in model file)

Q Q


Enter a pump curve based on size requirements

TEST7 (SI).FTH / Test 7a

Data is:

40 meters at 0 m3/hr



Data is already setup in a file

Import from file PUMP7A (SI).DAT

Change control valve from PDCV to FCV


Add 0.7 bar (70 kPa) pressure drop to valve after pump TEST7 (SI).FTH / Test 7B)

Review failure states of FCVs

Hint:

Morph the stop valve after the pump by dragging a control valve on top of it while holding down the CTRL key, then set as PDCV at 0.7 bar

Supply Tank Pump Tee (Simple) Elbow (Standard)

FCV FCV

Receiver Tank

Valve

Control Valve Can't Achieve Setpoint

Control valves (flow or pressure) can end up in a situation where they cannot control to the desired control setpoint

This indicates the desired control point cannot be obtained unless the valve acts like a pump

There are three actions to not achieving the setpoint:

Always Control (Never Fail) - add pressure if required (default)

Go to the valves full open state

Close the valve

In applications with multiple flow control valves in parallel, multiple valves may not achieve the setpoint simultaneously

Any control valve that cannot control to its setpoint will go to its "action if setpoint not achievable"

Once this action is taken, it will not return to its control capability

Control Valve Can't Achieve Setpoint (cont.)

When control valves fail, AFT Fathom will set failed valves to their failure position and re-run the model to determine if the remaining control valves can now control

Consider a system with three FCVs in parallel, specified to fail open if there is insufficient upstream pressure

With all three controlling, the system flow and corresponding upstream pressure drop may result in insufficient pressure for some, or all, of the valves to control.

Fathom initially runs the model with the valves in the never fail mode. Failed valves will have added pressure. The valve adding the greatest magnitude of added pressure will be set to the fail open mode specified and the model re-run.

This process will continue until no valves are adding pressure, thus determining the combination of valves that may operate at their setpoint.

Control Valve Can't Achieve Setpoint (cont.)

Pressure control valves can lose control for two reasons:

Insufficient upstream pressure

Excessive downstream pressure

The user can assign different actions for each of these cases

Heat Loss in a Pipe

Calculate heat transfer in a pipe

Fluid is water at 65 degrees

Heat transfer is enabled when specifying the fluid

81

Model 4: Heat Loss in a Pipe

AFT Fathom -

Define the model components Inlet stagnation pressure is 3.5 bar

Inlet temperature is 65 degrees C

Flow is 4.5 kg/sec

All elevations are zero

82

Model 4: Heat Loss in a Pipe (cont.)

AFT Fathom -

Pipe properties Length is 150 meters

Steel 4 inch (9.72 cm ID) Schedule 80

Add insulation to the pipe Ambient temperature is 10 degrees C

There is one layer of insulation 3 cm thick with a thermal conductivity of 3.5 W/m-K

External convection coefficient is 60 W/m^2-K

Fluid internal convection coefficient is calculated by Fathom using a correlation, and the pipe wall resistance is calculated using the material database

Models\Fathom Models\Heat Transfer.fth

83


AFT Fathom -

84


AFT Fathom -

Specify Heat Rate and Inlet/Outlet Temperatures in the output

Remove head terms (like dH in pipes)

85


AFT Fathom -

Specify insulation temperatures in the output

This is done on the Heat Transfer tab

86


AFT Fathom -

What is the exit temperature (deg. C)?

What is the Heat loss (kW)?

87

Model 4: Heat Loss in a Pipe - Output

AFT Fathom -

What is the maximum insulation surface temperature (found on the Heat Transfer tab)?

88

Model 4: Heat Loss in a Pipe Output

AFT Fathom -

Heat Exchanger Modeling

Heat Exchanger

In AFT Fathom heat exchangers can be modeled: as hydraulic only (e.g., a constant property model), or

as hydraulic and thermal

AFT Fathom uses the effectiveness-NTU method based on the heat exchanger geometry chosen

Alternatively, users can - specify a constant heat rate to or from the heat exchanger

specify a heat rate which is a function of temperature

specify the exit temperature of the heat exchanger, and let Fathom determine the amount of heat transfer that results

specify the temperature or enthalpy change

The assigned heat rate and assigned exit temperature are useful for sizing heat exchangers

90

Heat Exchangers Tube Model

Heat exchangers have a special pressure loss model called Tube Configuration

Pressure loss is calculated based on tubes, passes, scaling, etc.

91

Heat Exchanger Thermal Linking

A heat exchanger can be thermally linked to another heat exchanger

This can represent the hot and cold side of a single heat exchanger, with separate fluid loops

Models\Fathom Models\Turbine Cooling.fth

92

Heat Exchanger Thermal Linking

93

Scenario Manager

Scenario Manager

The Scenario Manager allows you to keep variants of a model all with the same model

When changes are made to the base model, they are automatically passed downward

Changes at lower levels do not pass upwards

Current Workspace

scenario

Scenario tree

Create a new

scenario by clicking

here

Rename, delete, clone,

promote & save

scenarios by clicking

here

Notes can be added

for each Scenario

Quick Access Panel

The Quick Access Panel provides convenient utilization of all of the features of the Scenario Manager.

Types Of Changes

The types of changes that can be made are very broad

Junctions can be turned on and off to evaluate different operating conditions

Pipe and junction data can be varied to parametrically evaluate competing designs

You can build an existing system as your base model then add to the system to evaluate expansion possibilities on the existing

system

You can easily evaluate different working fluids by setting them up as different children scenarios

You can compare a newly-built clean system to one that has been in service for a period of time with worn/corroded pipes,

etc.

Data Propagation

Changes to ancestors propagate to all descendants if the descendant data has not been modified

Changes to descendents never propagates to ancestors

Data Propagation (cont.)

Base

Child #1

Gr. Child #1

Diameter

3

__

__

Length

25

__

__

For many users, it is easiest to grasp Scenario Manager when it is explained

how the coding logic is actually

implemented

Blank fields for children, grandchildren, etc., mean to look to the parent for the

data If the parent is blank, then look to the

grandparent

The Base Scenario never has blank fields

Here Child #1 does not have a blank field, so its Diameter would be 2, not 3

Gr. Child #1 would have a Diameter of 2 Both still have Lengths of 25

Base

Child #1

Gr. Child #1

Diameter

3

2

__

Length

25

__

__


Changing the Base Scenario Diameter from 3 to 6 would not impact

Child #1 or any descendents in that

line

Changing the Length from 25 to 40 would also change the length in Child

#1, Gr. Child #1, and any

descendents of Gr. Child #1

Base

Child #1

Gr. Child #1

Diameter

3

2

__

Length

25

__

__

Base

Child #1

Gr. Child #1

Diameter

6

2

__

Length

40

__

__


Even if the Gr. Child #1 has the same Diameter as the Base, it is not

linked to the Base because it and its

parent are not blank Any change to the Base Diameter would

not affect any descendent because Child

#1 is not blank

If the Diameter in Child #1 is changed to be the same as the

Base, it will be blanked out the next time the scenario is loaded

And so will Gr. Child #1, if its Diameter is also the same

Base

Child #1

Gr. Child #1

Diameter

3

2

3

Length

25

__

__

Base

Child #1

Gr. Child #1

Diameter

3

3

3

Length

25

__

__

Base

Child #1

Gr. Child #1

Diameter

3

__

__

Length

25

__

__


Here, Child #1 would have the following:

Diameter = 2

Length = 25

Changes to Base Diameter will not affect Diameter

Changes to Base Length will affect Length

Here, Gr. Child #1 would have the following:

Diameter = 2

Length = 15

Changes to Base Diameter will not affect Diameter

Changes to Child #1 Diameter will affect Diameter

Changes to Base Length or Child #1 Length will not affect Length

Base

Child #1

Gr. Child #1

Diameter

3

2

__

Length

25

__

15

Ancestral Data

Ancestral source of data can be viewed for all pipes and junctions in Model Data

Scenario data can be colored for

easier viewing

Scenario names shown at left

Parameters which change are

highlighted

Links to Parent

A link to a parent may be re-established by returning the attribute to the same value as that of its parent

This can be done manually be entering the value or selecting Same As Parent from within a pipe or junction Property window,

Solution Control or System Properties.

Links are identified by comparing attribute values on a pipe or junction number by number basis.

This means that renumbering a scenario will break all links with its parent (since numbers must be unique)

You can make a pipe have the same attribute as its parent by choosing Copy Data From Pipe: Parent Pipe Data

Junctions function similarly

Links to Parent (cont.)

Example Model

A piping system will be used to transport liquid methane, propane, and ethane at cryogenic conditions

Supply is at -100 deg. C

The system will supply only one tank at a time

Pipe is Stainless Steel ANSI schedule 40S and is very well insulated (no heat transfer)

Supply is pressurized to 35 barG and storage tanks to 30 barG

Both valves have Cv = 25

Using Fathom build all of these scenarios in a single model (cryo1 (SI).fth)

What is the flow rate for all cases?

Models\Fathom Models\cryo1.fth

Example Model (cont.)

After building all the design cases, it is discovered that pipe 1 should have been 16 inch (39.8 cm ID) schedule 5S, not 12

inch (31.6 cm ID) schedule 40S (cryo1a (SI).fth)

Make this change to the model and review the effects

Flow rates to tanks using 12 inch (30.48 cm ID) pipe

Flow rates to tanks using 16 inch (38.9 cm ID) pipe

A B

Methane 87.2 87.5

Ethane 63.4 63.7

Propane 58.9 59.3

Flow Rate To Tank (m3/hr)

A B

Methane 87.2 87.5

Ethane 63.3 63.7

Propane 58.9 59.3

Flow Rate To Tank (m3/hr)

Answers to Example

Example Model (cont.)

Depending on how you arrange the scenarios, the Scenario Manager might look like this:

View of Model Data Scenarios

View of Output Scenarios

AFT IMPULSE

Transient Analysis

112

Overview of Transient Analysis Transient phenomenon occurs in a liquid piping system when

some event causes a departure from steady state.

Transient condition is the process the piping system experiences

as it adjusts to the new conditions.

Transient can be caused by many events including

Valve closure or opening (in full or in part)

Pump speed change

Relief valve cracking open

Tank pressurization

Periodic pressure or flow conditions

113

Transient phenomenon can occur in any liquid piping system

Other terms which have been used are

Waterhammer

Fluidhammer

Hydraulic Transients

Fluid Transients

Surge

The term waterhammer confuses some, because it implies a process only in water systems

114

Overview of Transient Analysis

Transient can be caused by different physical mechanisms

There is no universal terminology for these mechanisms so the terminology here is for discussion purposes

1. Thermodynamic Transient Liquid acceleration caused by local phase change

2. Slug Transient Liquid flows into an evacuated pipe system or when there are

distinct liquid slugs and gas pockets

When liquid contacts equipment or direction changes (elbows) pressure spikes can occur

3. Mechanical Transient Caused by equipment or component operational changes

Pump trips, valves closed, etc.

This is the type of waterhammer that AFT Impulse can model

115

Types of Transient

The magnitude of a transient is dependent on the wavespeed of the liquid

The wavespeed () is dependent on the:

liquid acoustic velocity

pipe modulus of elasticity (E), wall thickness (t), and material Poisson Ratio ()

pipe restraints

A useful equation for theoretical pressure surge is given by the instantaneous waterhammer equation

116

Instantaneous Transient

=

Most engineers believe the instantaneous waterhammer equation defines the maximum possible pressure from

waterhammer.

This is incorrect. Several real world affects can increase the waterhammer pressure:

Pipe friction

Cavitation

Network effects (superposition of pressure waves)

117

Instantaneous Transient (cont.)

Code Compliance

Once the overpressure is calculated, What should the designer do with

this value?

The answer to this question depends on the code being used.

ASME Code for pressure piping B31.4. Pressure Transportation Systems for Liquid Hydrocarbons and Other Liquids.

B31.4 refers directly to the maximum value of the overpressure,

establishing a limit of 10% above the design pressure.

ASME Code for pressure piping B31.3. Process Piping

The maximum stress produce the loads created by the surge pressure

shall not exceed: 1.33 Sh (Sh=allowable stress for the operating

temperature).

AFT Impulse

120

Waterhammer Sequence

a

V=Vsteady

V=0

a

b

c

d

a

V= Vsteady

V=0

a

V= Vsteady

V=0

a

V= Vsteady

V=0

121

Waterhammer Sequence 0 < t < L/a

P

V

Vsteady

DPinstantaneous

Valve closed instantaneously at t=0

Psteady

x

x

a

V=Vsteady

V=0

122

Waterhammer Sequence L/a < t < 2L/a

a

V= Vsteady

V=0

P DPinstantaneous


Psteady

x

V

x

-Vsteady

123

Waterhammer Sequence 2L/a < t < 3L/a

a

V= Vsteady

V=0


P

DPinstantaneous Psteady

x

V

x

-Vsteady

124

Waterhammer Sequence - 3L/a < t < 4L/a

a

V= Vsteady

V=0


P

DPinstantaneous Psteady

V

Vsteady

x

Mass / continuity equation

Momentum equation

125

Fundamental Equations

2

+

= 0

1

+

+ sin +

2= 0

Where : a = wavespeed V = velocity x = distance along pipe P = pressure t = time g = gravitational constant a = slope of pipe f = friction factor D = diameter of pipe

Note: These are only the primary equations, not the complete set.

By combining the mass and momentum equations linearly and

substituting mass flow rate, , for velocity, V, one obtains

Integrating along the characteristic line from A to P yields the positive characteristic

126

Method of Characteristics

t = 0

t = D t

t = 2 D t

t = 3 D t

t = 4 D t

t = 5 D t

x = 0 x = L

A B

P

x = i x = i+1 x = i-1

C + C -

+

+ +

22 = 0

+

+

+

22

= 0

+

+ +

22 = 0

(Note: a similar equation can be written for the negative characteristic)

Introducing two convenient parameters

Impedance

Resistance

127

Method of Characteristics (cont.)

t = 0

t = D t

t = 2 D t

t = 3 D t

t = 4 D t

t = 5 D t

x = 0 x = L

A B

P

x = i x = i+1 x = i-1

C + C -

Note that after the initial calculations the impedance and resistance have constant property values for each pipe,

except for the friction factor, f

=

=

22

Where:

A = cross sectional area

The Transient Solver requires the following:

Initial steady-state flow rates in all pipes

Initial pressures at all junctions

Initial states of all junctions

Pumps on or off

Valve open or closed

Check valves open or closed

Etc.

Pipe resistance (friction factors)

128

Steady-State Data in Transient Solver

129

AFT Impulse Examples

Determine the surge pressures in an ammonia transfer system when a valve is closed in 0.5, 1 and 2 seconds

All pipe is steel with standard wall thickness, thin-walled anchored upstream Models\Impulse Models\Ammonia Transfer

System Valve Transient.imp

130

Model 1: Valve Closure Surge Transient

Surface Elev. = 6 m Surface Pressure = 1.72 MPa(g) Pipe Depth = 1.5 m

P1 L = 30 m 8 inch (20.3 cm ID)

Ammonia at 24C 0 to 5 seconds Model Cavitation

Surface Elev. = 12 m Surface Pressure = 1.72 MPa(g) Pipe Depth = 6 m

P3 L = 46 m 10 inch (25.5 cm ID)

Abrupt Expansion Elevation = 0 m

Valve Elevation = 0 m t (sec) Cv 0 1000 ? 0

P2 L = 91 m 10 inch (25.5 cm ID)

1 2 3 4

131

Model 1: Valve Closure Model

132

Model 1: Valve Closure Valve Input

Results

(*) The first two cases yield different pressures when the

sectioning is varied

This is a result of the cavitation model

The 2 second closure case does not cavitate

133

Model 1: Valve Closure - Results

Closure Max Stag. Pressure* Time (sec) (MPa(g)) 0.5 4.183 1 4.145 2 2.502

Animation for 2 second closure case

134

Model 1: Valve Closure - Animation

Determine the surge pressures in gasoline product pipeline when the pumps trip

Steel pipes, standard schedule, thin-walled anchored upstream

135

Model 2: Pump Trip Surge in a Pipeline

136

Model 2: Pump Trip Surge - Input

137

Model 2: Pump Trip Surge Gasoline

Models\Impulse Models\Gasoline Pipeline Pump Trip.imp

138

Model 2: Pump Trip Surge Pump Data

The one pump junction represents 3 pumps in parallel

139


140


141

Model 2: Pump Trip Surge Maximum and Minimum Pressures

142

Model 2: Pump Trip Surge Animate Pressures

Webinar Agenda


Industry Applications


AFT impulse


Pipe Network Design Challenges and AFT products

Overview of Transient Analysis

Types of Transient

Instantaneous Transient

Code Compliance

AFT Impulse Examples

Valve Closure Surge Transient

Pump Trip Surge in a Pipeline

Spray System Transient

Q/A session

143

Models\Impulse Models\Spray System Transient.imp

Find how long it takes for the flow rate to come up to the full flow of 22.7 m3/hr at each spray from the closure state

Pipe data:

Steel pipe, all schedule 40, standard roughness of 0.004572 cm

Fluid is water at 21 deg. C

Inlet stagnation pressure is 1200 kPa

Spray nozzle data:

Sprays discharge to atmosphere and open in 0.1 second

Flow Area = 3.23 square cm, Discharge coefficient = 0.6

144

Model 3: Spray System Transient

Time (sec) CdA (cm2)

0 0

0.1 1.94

10 1.94

145

Model 3: Spray System Model Layout

4 inch

(10.2 cm ID)

L=152 meters L=152 meters 8 inch

(20.3 cm ID) 8 inch

(20.3 cm ID)

L=3 m

L=3 meters

1-1/2 inch

(4.1 cm ID)

L=3 meters

1-1/2 inch

(4.1 cm ID)

L=3 meters

1-1/2 inch

(4.1 cm ID)

L=3 meters

1-1/2 inch

(4.1 cm ID)

L=3 meters

1-1/2 inch

(4.1 cm ID)

L=3 meters

1-1/2 inch

(4.1 cm ID)

L=3 meters

1-1/2 inch

(4.1 cm ID)

L=3 meters

1-1/2 inch

(4.1 cm ID)

El=0.3 meters El=0.3 meters

El=0.3 meters

El =

3 m

ete

rs

L=0.5 m

1-1/2 inch

(4.1 cm ID)

Typical

146

Model 3: Spray System Model Layout

147

Model 3: Spray System Spray Data

It takes about 0.85 seconds for the final spray to reach 22.7 m3/hr

After slightly less than 1 second the flow drops below 22.7 m3/hr

148

Model 3: Spray System - Results

Nearest Supply

Farthest From Supply

AFT ARROW

Compressible Flow

149

Arrow 5.0 Overview

Models compressible network pipe systems

High to low velocity gas systems High to low pressures

Implements highly advanced graphical interface very similar to Fathom

Models open and closed systems Accurately models

Real gases Heat transfer Highly compressible (sonic and near sonic) systems

Offers broad range of innovative reporting features Balances flow and energy throughout the system Offers customizable component and property databases Includes high accurate steam/water properties to ASME Modules for:

Goal Seek & Control Cost calculations

151

Arrow Add-On Module Overview

GSC

Automatically determines input variables that will yield specified output values

Extends Arrows control simulation capabilities to include remote sensing

CST

Supports cost databases for piping, fittings, valves, pumps and other system components

Analyzes first and life cycle cost of piping/pump systems

Integrates system hydraulic design and cost

152

AFT Arrow Approach to Compressible

Flow

153

Solve all governing equations simultaneously Include all thermal and real gas effects Balance mass and energy throughout the network

Implement special flow and energy balance iterative methods

Offer several solution methods to increase flexibility Encapsulate powerful solution method in an easy-to-use

graphical Windows interface

Solution Methods

154

AFT Arrow offers six solution methods Two lumped methods Four marching methods

Defining Gases in the System

155

Model your system using real or ideal gases AFT Standard: 28 gases to choose from ASME Steam Tables CHEMPAK Database

Heat Transfer - Pipes

156

Heat transfer can be calculated using one of four models

Adiabatic Isothermal Convective heat transfer Constant heat flux

Database

157

AFT Arrow offers custom database for these type of data

Components Fluid Properties Pipe sizes Insulation properties Fitting and losses Output configuration

Databases: local or network

Typical Applications

158

Pipe and duct sizing Compressor/Fan, control valve, relief valve: sizing and

selection

Simulating system operation and component interaction Choked Flow calculations Evaluating Heat Transfer in pipes and heat exchangers Trouble shoot existing systems / cause of operational

problems

Arrow 5.0 Scenario Manager

159

Scenario Manager The Scenario Manager allows you to keep variants of a model all with the

same model

When changes are made to the base model, they are automatically passed downward

Changes at lower levels do not pass upwards

160

AFT Arrow Examples

Building a model

161

Model a Compressed Air System

162

Model a Compressed Air System

Models\Arrow Models\Compressed Air System.aro

Four machine tools are supplied air for operations

The air is taken from outside the building (P = 14.7 psia), and design conditions are that air temperature can vary from 0

deg. F to 110 deg. F.

The compressor has the following data for stagnation pressure: 12 psid at 0 lbm/s, 10 psid at 0.5 lbm/s, and 6 psid

at 1 lbm/s

Efficiency is not known with certainty, but is expected to be about 80% to 90% - use the Determine From Efficiency Data option for the Compression Process Thermodynamics

163

US

Model a Compressed Air System (2)

The nozzles at the tools (modeled as valves) have a pressure drop of 8 psid at 0.2 lbm/s

Discharge is to atmospheric pressure (make them exit valves)

Hint: Use "Fill as Quadratic" feature to create a curve

The pipes are uninsulated, sch40 steel with external heat transfer coefficients that vary from 1-10 Btu/hr-ft2-R,

exchanging heat with the internal building ambient which can

range from 70 to 75 degrees.

The pipe at the compressor inlet is heavily insulated (consider it adiabatic)

164

US

Model a Compressed Air System (3)

The branches can be modeled as lossless

Use Redlich-Kwong and Generalized for the equation of state and enthalpy model

Neglect elevation changes

The machine tools are sensitive to temperature, but the manufacturer says they can compensate for this if they know

the extremes of delivery temperature the tools will see. What

are the (static) temperature extremes at the tools?

Hint: Compressor temperature rise increases with decreasing efficiency

Hint : Look at pipes P6-9 outlet temperatures for tool supply temperatures

165

US

Dynamic mixing

166

Assemble non-reacting mixtures (using Chempak Database) Analyze dynamic mixtures resulting from intersecting flow streams Models\Arrow Models\Mix1.aro

Refinery Relief System

167

US

P1

L=50. 3 inch

schedule 40

P2

L=25. 3 inch

schedule 40

P3

L=50. 3 inch

schedule 40

P4 L=25.

4 inch schedule 40

P5

L=50. 3 inch

schedule 40

P6

Main Relief Line L=150 6 inch schedule 40

J5 Tee or Wye

J6 Tee or Wye

PIPE UNITS L= feet

J1 Methane Process

200 psia, 300F

J2

Ethane Process 200 psia, 300F

J3

Propane Process 200 psia, 300F

J7 Primary

Relief Valve

CdA=15 in2

J4 Bend

K=0.538

Refinery Relief System

Models\Arrow Models\Test10.aro

A new emergency relief system at an oil refinery is being considered and you have been called as a consultant to

evaluate the process calculations (model TEST10.ARO)

The system provides relief to processes for methane, propane and ethane (use Chempak to specify three fluids at the same

time)

Each process is at 200 psia when the relief event occurs

The process engineer has evaluated the relief capacity at the minimum process temperature of 300 F

The elbow is a standard elbow, and model the tees as simplified

168

US

Refinery Relief System (2)

The relief valve CdA is 15 sq. inches (assume K = 0 since this will choke)

Discharge pressure is 1 standard atmosphere

All pipe is steel

Assume adiabatic flow

Determine the following:

Relief capacity (i.e., flow rate) of each process

Mass and mole fraction of the discharge mixture for environmental impact assessment

Hint: in Output Control, use Concentration Mass and Mole Fraction

169

US

Model Control Valve (condensation)

Fluids in the AFT Standard database do not have saturation line data

It is not possible to evaluate condensation

Chempak fluids and the ASME Steam data do have saturation line data

Use steam data from the Chempak database to evaluate whether condensation will occur. Does it?

TEST3.ARO - "Chempak - No Insulation" Scenario

170

US

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