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()- -By: , , Oktarian W.L,

1Catholic Kwandong UniversityStudy on Small Magnus Windmill with Auto-rotation Blade (1)OUTLINE2Catholic Kwandong University1. INTRODUCTIONWind energy is one of renewable energy resource with less environmental effect

Our objective is to develop small windmill by looking several parameter:soundscape;aesthetical view; fluid mechanics3Catholic Kwandong University

The purpose of this study is to develop small horizontal rotor windmill while using Magnus effect on the blade. Magnus effect will generate lift force to make self-propelled blade.

3This study focusing on blade rotational characteristics by using Magnus effect.

Magnus effect is phenomenon that happens on spinning object which producing perpendicular rotational lift force to the flow direction.

4Catholic Kwandong University

Fig 1-1. Magnus EffectMagnus Effectthe spinning ball moves through the air it will create a pressure difference between its two sides according theBernoullieffect. The interaction between the air layer on the side of the ball that rotates in the opposite direction of the ball movement and the surrounding air creates a low-pressure area. This will suck the ball and curve its trajectory.45Model OverviewCatholic Kwandong University

Fig 1-2. Overview of Magnus Windmill2. EQUIPMENT AND METHODS62.1. Laboratory EquipmentsExperiment conducted in Catholic Kwandong University using wind tunnel experiment. The equipments shown in Table 2-1

Catholic Kwandong University

Table 2-1 Equipments2. EQUIPMENT AND METHODS72.2. Test ModelCatholic Kwandong University

a) 1 piece Bladeb) 2 pieces BladeFig.2-1. Overview of experimental blade modelsBlade model made from acrylic pipe using same width and length (50 mm & 160 mm; for 2 pieces blade is 80 mm). Cap made from acrylic plate with various diameter 60 mm, 75 mm, 90 mm and 105 mm. 8Catholic Kwandong University0.5 overlapping (a/c) selected for optimum Magnus effect.

Remarks:c = 50 mma/c = 0.5D = 75 mmFig.2-2. Blade Overlapping (a/c) Model Section9Catholic Kwandong UniversityTable 2-2. Blade Model ProfileBlade Model Profile

10Catholic Kwandong UniversityTable 2-3. Experiment Wind Speed DescriptionExperiment Wind Speed Data

11Data obtained from this experiment used for calculating Power (Pe) and Tip Speed Ratio () . The equation listed below.

Catholic Kwandong University2.3. Non-dimensional Test ResultPe= r rps wVT= 2r rps=

Remarks:Pe = Power (Nm/s)w = Blade weight (N)r = rotor radius (m) V = Wind speed (m/s) Rps = round per second VT= Tip speed (m/s)123.1. RPM VS Wind speedCatholic Kwandong University3. RESULT AND DISCUSSIONFig 3-1. RPM and Wind speed by Cap sizea) 1 Piece Bladeb) 2 Pieces Blade

The 0.8D Cap show the highest RPM compared with the other Cap on both models

12133.2. Tip Speed Ratio VS Wind speedCatholic Kwandong UniversityFig 3-2 Tip speed Ratio and Wind speed by Cap sizea) 1 Piece Bladeb) 2 Pieces Blade

The 0.8D Cap show the highest RPM compared with the other Cap on both models

13143.3. Power VS Wind speedCatholic Kwandong UniversityFig 3-3 Power and Wind speed by Cap sizea) 1 Piece Blade b) 2 Pieces Blade

The 1.4D Cap show the highest power compared with the other Cap on both models. Power gap in high-speed wind relative large compared with low-speed wind. During high-speed wind in 2 stage blade models has relative little gap, considering this condition 2 stage blade models is more safe than 1 stage blade models

144. CONCLUSION15Catholic Kwandong UniversityThe result from experiment are:Small Cap size make high RPM and Tip Speed Ratio.Big Cap size make high power.RPM and Tip Speed Ratio by 1 piece blade and 2 pieces blade are similar. 2 pieces blade produce more power and stability. By using good configuration, 1 and 2 pieces blade make low-noise on several wind speed.By our students opinion this model has good design.

16Catholic Kwandong UniversityThank youforyour attention