8/6/2019 FMM_ND07

1/4

Reg. No. :

R 3450B.E./B. ech.DEGREEEXAMINATION,NOVEMBER/DE EMBER2007.

Third Semester(Regulation 2004)

Aeronautical EngineeringME T2O2 FLUID MECHANICS AND MACHINERY

(Common o Automobile Engineering/NlechanicalEngineering/MechatronicsEngineering/ProductionEngineering)

(Common o B.E. (Part-Time) SecondSemester)Regulation 2005)Time : Three hours Maximum : 100marks

Answer ALL questions.PARTA - (fO x2 = 20 marks)

1. How does the dynamic viscosity of (a ) liquids and (b) gases vary withtemperature?2. What is the differencebetweengaugepressureand absolutepressure?3. Define stream line. What do stream lines indicate?4. Write the Bernoulli's equation n terms of head. Explain each erms.5. What is the physical significanceof Reynold'snumber?6. Define the terms : Drag and Lift.7. Differentiate between the turbines and pumps.8. Definespecificspeed.

www.

Maana

vaN

.com

8/6/2019 FMM_ND07

2/4

9. What do you mean by manometric efficiencycentrifugal pump?

and mechanicai efficiency of a

10. Define slip of a reciprocating pump.

PARTB-(5x 16 = 80 marks)11. (a) ( i ) When a pressure of 20.7 MN/m2 is applied to 100 litres of a liquid

its volume decreasesby one litre. Find the bulk modulus of theliquid and identify this liquid. (6)

(10)ii ) State and prove Pascal's law.Or

The barometric pressure at sea level is 760 mm of mercury whilethat on a mountain top is 735mm. If the density of air is assumedconstant aL L.2 kglrrr},what is the elevation of the mountain top? (8)Calculate the capillary effect n millimetres in a giass tube of 4 rnmdiameter, when immersed in (1 ) water and (2) mercury. Thetemperature of the liquid is 20"C and the values of surface tensionof water and mercury at 20'C in contact with air are 0.0735N/mand 0.51 N/m respectively.The contact angle for water 0 = 0 andfor mercury 0 = 130".Take specificweight of water aL20"C as equalto 9790 N/m3. (8)

12. (a) (i ) Obtain an expression for continuity equation in Cartesiancoordinates. (8)

(i )b)

(ii)

(ii) The two dimensional stream function forV =9 + 6x - 4y +7xy . Find the velocity potential.

flow is(8)

Or(b) (i) State if the flow representedby

u=3x+4y andu =2x -Jy

is rotational or irrotational. Find the potential function, f the flowis irrotational and vorticitv. f it is rotational. (8 )

R 3450

www.

Maana

vaN

.com

8/6/2019 FMM_ND07

3/4

(ii) A 300mm x 150mm venturimeter s provided n a vertical pipe inecarrying oi l of relative density 0.9, the flow being upwards. Thedifferential U tube melcury manometer shows a gaugedeflection of250 mrr,, calculate the dischargeof oil, if the coefficient of meter is0.98. (8)

13 . (a) Obtain an expression or Hagen-Poiseuillelow. Deduce he condition ofmaximum velocitv. (16)

(b )Or

A flat plate 1.5m x 1.5m movesat 50 km/h in a stationaryair of density1.15 kg/m3. If the coefficient of drag and lift are 0.15 and 0.75respectively, determine (i) the lift force (ii) the drag force (iii) theresuitant forceand (iv) the power equired to set the plate n motion. 16)Obtain an expressionor the workdoneper second y water on the runnerof a Peltonwheel. Hence derive an expression or maximum efficiencyofthe Pelton wheel giving the relationship between the je t speed andbucketspeed. (16)

OrA Pelton wheel is having a mean bucket diameter of 1 m and isrunning at 1000 pm. The net head on the Pelton wheel s 700m. ifthe side clearanceangle is 15o and discharge through nozzie is0.1 m3/s, ind (1) power availableat the nozzleand (2) hydraulicefficiency f the turbine. Take C, = 1. (8 )

L4. (a)

(b ) (i)

( i i A turbine is to operate under a head of 25 m at 200 rpm. Thedischarges 9 rn3/s. f the efficiency s 90%,determine, pecific peedof the machine,powergeneratedand type cf turbine. (8 )A centrifr-rgalpump delivers water against a nei head of14.5metres and a designspeedof 1000 pm. The vanes are curvedback to an angleof 30"with the periphery.The impeller diarneter s300 mm and outlet width 50 mm. Determine the dischargeof ttre

1 5 . ( a ) ( i

pump if manometric efficiency is 95Vo.(ii) A single acting reciprocatingpump running at 50 rpm, delivers0.01m3/sof water. The diameterof the piston s 200 mm and strokelength 400 mm. Determine the theoretical dischargeof the pump,coefficient of discharge and slip and the percentage slip of the(8 )

(8)

pump.Or

R 3450

www.

Maana

vaN

.com

8/6/2019 FMM_ND07

4/4

(b) (i )

(ii)

Explain the working principles of vane pump and gear pump withneat sketches. (8 )A reaction turbine works at 450 rpm under a head of L20 m. Itsdiameter at inlet is 120 cm and the flow area s 0.4m2. The anglesmade by absolute and relative veiocity at inlet are 20o and 60'respectively, with the tangentiai velocity. Determine, the volumeflow rate, the power developedand the hydraulic efficiency. (8)

R 3450

www.

Maana

vaN

.com