An Experiment on the Electric Energy Performance of the Wind Turbine Rotors

Transcription

1 Jurnal f Applied Sciences 4 (1): , 2004 ISSN Asian Netwrk fr Scientific Infrmatin An Experiment n the Electric Energy Perfrmance f the Wind Turbine Rtrs Ali Vardar and Bülent Eker Department f Agricultural Machinery, Faculty f Agriculture, Trakya University, Tekirdag, Turkey Abstract: First f all 270 sets f miniature wind turbine rtrs with different prperties were prduced by using sme NACA prfiles. The prduced 270 sets f rtrs f different frms were tested in a wind tunnel. During the test, the electric vltages and the electric currents that each rtr frm generated under different wind speeds were measured. Then the perfrmance f each rtr frm was laid dwn in view f such measurements. The rtr frm made f NACA 4412 prfile, with tw blades, which are cupled t the rtr with a twisting angle f 0 and a blade angle f 5 was defined as the rtr frm yielding the highest perfrmance. The energy which was generated by this rtr frm was 161,73 mw. Key wrds: Wind turbine, rtr blade, electric energy perfrmance INTRODUCTION Nmenclature 8 : tip speed rati Energy is the mst imprtant pwer n the earth. But B : number f blades the electric energy that is prduced n the earth causes C : tip chrd width (m) envirnmental prblems f which reasn lies at its surce. D : rtr diameter (m) Nwadays has cme t use such energy surces, which 2 A : rtr crss sectin area (m ) are clean and sustainable. d : rtr diameter (m) While investigating slutins fr the energy prblem, N : electric energy generated by electr mtr (mw) sme sectrs shuld als cnsider the alternative t U : electric vltage prduced by electr mtr (V) demand less energy frm the natinal energy netwrk by I : electric current prduced by electr mtr (ma) prducing their wn energy, rather than prducing mre. In view f this, small and medium size peratins culd MATERIALS AND METHODS prduce their wn energy in rder t meet their energy requirement. Blades: The blades that were used during the tests are Clean and sustainable energy surces by which small made f Balsam (Fig. 1) tree with a cnsiderably lw 3 [1] and medium size peratins culd prduce their wn strength and with a density f g cmg. The blades energy are miscellaneus. One f thse energy surces is are designed with a rtr diameter f 310 mm and a hub the Wind Energy. diameter f 48 mm (the cmpnent at the centre f the The installatin cst f giant wind turbines that are rtr that cnveys t the blades the wind incming t the intended and designed t generate electric energy is very rtr centre) and a blade length f 130 mm (Fig. 2). high therefre small and medium size peratins culd The guidelines that are recmmended by NACA were hardly affrd it. Fr this reasn, high-perfrmance wind [2] cnsidered in selecting blade prfiles. turbines that culd be affrded by small and medium size The number f blades f the blade prfiles used [1] peratins must be develped. during tests as well as their tip speed ratis culd be Attaining a high perfrmance frm a wind turbine cmputed by the fllwing equatin (3): depends n a variety f factrs. Amng such factrs are the height f the wind turbine and the rtr area. Still 80 (1) 8 anther ne is the blade structure. The factrs as the B turbine height and the rtr area shall require a larger turbine size. This in turn will directly influence the cst. When the number f blades used during test is taken But ptimisatin f the blade structure shall nt require tw, three and fur in the abve equatin, the tip speed any increase in size and thus its cst will be lw. ratis shall be as fllws: Crrespnding Authr: Dr. Ali Vardar, Department f Agricultural Machinery, Faculty f Agriculture, Trakya University, Tekirdag, Turkey, Tel: (192) avardar@tu.tzf.edu.tr 144

2 B = = 6,325 Tw different types f Multi-meter (Fig. 7) were used B = = 5,164 fr the purpse f measuring the electric vltage and the B = = 4,472 electric current during the tests. These tw Multi-meters had the same prperties. The standard cnnecting cables The ther dimensins f the blades culd be fund that were used in the Multi-meters were designed [3] by the cmputed 8 values. cnsidering the circuit t be used in the system. Current was serially cnnected t the circuit whereas vltage was C 4.D 8 2.B (2) parallel cnnected. A resistance f S was used in [5] the circuit. Fr each 8 and B value, blade width is fund 15 mm at the tip. The blade width value at rt is nt f much Wind tunnel tests: The anemmeter that was used fr the significance. Only, the value at the end must be higher purpse f measuring the wind speed was fitted 20 cm [3] than the ne at the tip. Therefre the rt value is taken inward f the tunnel exit, where the wind left the tunnel, in 30 mm fr the purpse f this study. a manner t permit a measurement culd be dne at the The ther characteristics f the blades that were used centre f the tunnel. With the aim t test the rtrs at in the test are defined by assigning t them the Frm different wind speeds, the wind speed values f 2, 3 and Cde Numbers. These characteristics are six different 1 4 msg were selected. The selected values were the NACA prfiles (Fig. 3) the blade angle, the twisting angle averages f the readings mnitred n the anemmeter f blades and the number f blades n the rtr. The while testing the rtrs. The wind speed prevailing at the prfiles used are NACA 0012, NACA 4412, NACA 4415, mment when the rtr t be tested was perated was set NACA 5317, NACA and NACA On the ther by gradually increasing the wind speed n the wind speed hand, the values that were taken as the blade angles are panel and then by reading the value n the anemmeter. 5, 8, 10 and 15 whereas 18 and 0, 10 and 20 are the The electric vltage and the electric current that were values that were taken as the twisting angles f blades. generated in the electr-mtr during the tests by means Rtrs with tw, three and fur blades were used. Number f the rtatin f the rtr were measured by the test f rtr frms, which were created by means f the [7,8] multi-meter under a fixed resistance f S. cmbinatin f these values is 270. Calculatins abut the test blades: The diameter f the Electr mtr: The RPM-Energy crrelatin f the electr rtr used in the tests is m. This value is als valid [4] mtr that was used in the tests is depicted in Fig. 4. [7] fr all ther rtrs. Assigning the value t the [5] The main characteristics f the mtr are as fllws : equatin N.3 shall reveal a rtr crss-sectin area f m. This value was used as a cnstant in all C Miniature, cntinuus, magnetic type mtr, [9] calculatins. C Length 35 mm, diameter 32.7 mm and height 38.6 mm C Shaft diameter 1.8 mm, shaft length 8 mm A B.d 2 C 2520 rpm at 6 V, 3900 rpm at 9 V and 4900 rpm at 12 V 4 (3) C Cntacts are external and perfrated As a result f the rtatin f the rtr with the effect f the wind speed, the electr-mtr generated an electric Test equipment: In this experiment, a wind tunnel in a pipe vltage and an electric current under a fixed resistance f shape, with an internal length f 2 m, a diameter f S. The electric vltage and the current were cm, ttal height m, ttal width 0.88 m and measured by the multi-meter. When these tw measured verall length 2.35 m was used (Fig. 5). On the tunnel values were assigned t the equatin N.4, the value f fitted a fan with a diameter f 35 cm, at a rated pwer f [10] the generated electric energy was attained. 250 W and a speed f 1400 rpm. The system perates under a vltage f 220 V and 50 Hz. Depending n the N = U. I (4) temperature and the density f the ambient air it is pssible t perate the system under a wind speed f RESULTS AND DISCUSSION 1[6] 5 msg. An anemmeter was used in rder t measure the The effects f the twisting angle and the blade angle wind speed during the tests. The said anemmeter als which are made in NACA blade prfiles as well as the made pssible t measure temperature and flw-rate in blade number cmbinatins f the rtr n the generated additin t the wind speed. The reslutin f the device electric energy were defined. The ptimum values fund 1 was 0.01 msg in 0.1 C (Fig. 6). are depicted in Table

3 Table 1: Perfrmance results f rtr frms (a) Blade Prfile: NACA 0012, Twisting Angle: 10, Number f Blades: 2; Blade Angle ( ) (b) Blade Prfile: NACA 4412, Twisting Angle: 0, Number f Blades: 2; Blade Prfile: NACA 4415, Twisting Angle: 0, Number f Blades: 2; (d) Blade Prfile: NACA 5317, Twisting Angle: 10, Number f Blades: 2; (e) Blade Prfile: NACA 23012, Twisting Angle: 0, Number f Blades: (f) Blade Prfile: NACA Twisting Angle: 0, Number f Blades: 2; Fig. 1: Blades designed accrding t the prfiles used Fig. 3: Blade prfiles used Fig. 2: Rtr blade size Depending n the results regarding the electric energies, which were generated by different rtr frms, the ne that was generated by the rtr made f NACA 4412 prfile, having tw blades, a twisting angle f 0 and a blade angle f 5 was 161,73 mw. The evaluatin that was cnducted as fr the electric energies generated by different rtr frms revealed that the best rtr was the ne defined in the preceding paragraph. 146

4 Fig. 4: Crrelatin between RPM f the electr mtr and the electric energy Fig. 5: Wind tunnel Fig. 6: Anemmeter In this experiment, wind tunnel tests were cnducted n 4 grups f turbine blade cnfiguratins under [11] different resistances. A perfrmance up t 360 Vlts X DC ma under the resistances f 51, 100 and 200 S was attained. In this experiment, rtrs with 3 blades, with a Fig. 7: Multi-meter used fr measuring the electric vltage and the electric current hub radius f 2.8 cm, a blade radius f 10 cm, a pitch angle f 8 and a twist angle f 0 were used. Eight different types f rtrs were used in this experiment. 6 f these rtrs had 3 blades whereas 2 f [7] them had 2 blades. The blade radii f these rtrs are between 12.5 and 15 cm. On the ther hand pitch angle at hub is between 9 and 21. The yields attained frm these rtrs are between 32.0 mw and mw. When the electric energy generated by different rtr frms are cnsidered, we bserve that the rtr frms which have generated the maximum energy are thse with NACA 4412, NACA 4415, NACA and NACA blade prfiles, a twisting angle f 0 and 10, with tw and three blades and blade angles f 5 and 8. The evaluatin als reveals that the blades with an electric energy f 0 are mre frequently fund in the rtr frms with a twisting angle f 20. In this experiment, in the mdeling designed with the blade prfiles NACA 0012, NACA 4412, NACA 4415, NACA and NACA 23015, the best result was [12] attained with NACA Als it was cncluded in this experiment that the 4 blade rtrs yielded better results. The independent review f the blade prfiles reveals that the rtr frm, with a NACA 0012 blade prfile, a twisting angle f 10, a blade angle f 8 and having tw blades yields the best result. Fr NACA 4412 blade prfile, the rtr frms yielding the best result are thse with a twisting angle f 0, blade angles f 5 and 8 with tw blades. Fr NACA 4415 blade prfile the rtr frm generating the highest electric energy is the ne with a twisting angle f 0, a blade angle f 8 having tw blades. We fund that the rtr frms made f NACA 5317 blade prfile has generated lwer electric energy when cmpared with ther rtr frms. Fr this blade prfile the 147

5 rtr frm with a twisting angle f 0 and a blade angle f 2. Dreese, J., Aer basics and design fil, user 15 with tw blades yielded the best result. guide, Capitla, Califrnia, USA. Fr the blade prfiles NACA and NACA Annymus, which were used in the experiment the rtr frms with a net/hugh0piggt/wpntes/index.htm. twisting angle f 0 and a blade angle f 5 with tw 4. Vardar, A. and B. Eker, 2003b. Select f Suitable Wind blades yielded the best result. Turbine Blades, 3e Electrtech, Istanbul, Turkey, Depending n the findings f the experiment, we can 105: suggest a wind turbine, which is made f NACA Vardar, A., A research n determinatin f the prfile. That the turbine f that prfile has n twisting fittest blade type, blade angle and blade psitin fr angle but has a blade angle f 5 is f utmst imprtance. establishing a wind turbine with Agricultural Aim in Als the rtr shuld have tw blades. In this experiment Trakya Regin, Graduate Schl f Natural and the rtr with these characteristics was defined as the Applied Sciences Ph.D. Thesis, Tekirdag, Turkey. rtr with the best perfrmance. 6. Vardar, A. and B. Eker, 2003c. A research n It will be pssible t get a higher perfrmance frm determinatin effect f axle pwer n wind turbine the wind turbine if we use the rtr frm that yields the blades structure, Agricultural Mechanizatin 21. best result. On the ther hand, in rder t get a better Natinal Cngress, Knya, Turkey, pp: result frm a rtr that perates at a lw perfrmance it 7. Annymus, will required t increase either the turbine height r the edu/faculty/birnie/engr102/102index.htm. rtr area. This means an additinal cst. But, a rtr that 8. Arin, S., Measurement Knwledge, Trakya yields the best perfrmance shall bth prmte the University Tekirdag Agriculture Faculty Publicatin efficiency f the wind turbine and incur a lwer cst. N: 97/261, Tekirdag, Turkey. The wind turbines that will be built by using the 9. Yavuzcan, Energy Technlgies, Ankara apprpriate rtr frms shall be a gd chice in meeting University Agriculture Faculty Publicatin N: 134, the energy requirements f small and medium size Ankara, Turkey. peratins. Als keeping the cst at a reasnable level is 10. Erna, H., Practical Electric and Applicatins f anther imprtant criterin in terms f its attractiveness. Mdern Electrnic, Inkilap Publishing Huse, Istanbul, Turkey, pp: ACKNOWLEDGMENTS 11. Annymus, edu/~cellier/engr102-pr3.pdf. This research is supprted by The Scientific and 12. Cskun, M.B., Mdeling f ptimal wind Technical Research Cuncil f Turkey (TUBITAK). The energy cnversin systems fr the rural areas f authrs acknwledge a great deal f Agricultural Turkey, Department f Agricultural Machinery, Machinery Department, Tekirdag Agricultural Faculty, Faculty f Agriculture, University f Ankara, Trakya University. Dctral Dissertatin, Ankara, Turkey. REFERENCES 1. Vardar, A. and B. Eker, 2003a. Sme prpses abut wind turbines fr Trakya Agricultural Regins II. Renewable Energy Surces Cngress, Izmir, Turkey, pp: