1、風力發電機製作及相關物理計算MAKING OF WIND TURBINEAND RELATED CALCULATION,香港理工大學應用物理學系學生翟振亨HKPUApplied Physics StudentChka Chun Hang,目錄,引言理論發電機的設計製作過程相關計算演示,Where do winds come from?風從哪裡來?,Because of the temperature differences(溫差) around the world,Surface Wind,Convection updraft of rising warm Air,What is wind t
2、urbine(風力發電機)?,Winds kinetic energy(動能) -electrical energy(電能),Theory理論,By Lenzs Law (冷次定律) Induced current(感生電流) opposes (對抗) the change of the magnetic force Heinrich Lenz 海因里希冷次,Theory理論,Theory理論,Induced emf-感生電壓,Where ,N is the number of turn of coil,B is the magnetic field strength(磁場強度)A is th
3、e area(面積) of the coil,Design-設計,Design-設計 (3D View),Design-設計 (3D View),Brace 支架,Design-設計 (3D View),Axle 軸,Design-設計 (3D View),Turbine 渦輪,Design-設計 (3D View),Rotor 轉片,Design-設計 (3D View),Coil 電線圈,Design-設計 (3D View),Supporting Base支撐底部,Design-設計 (3D View),Magnet 磁鐵,Material-物料,Screw(螺絲) x 8Bearing
4、(滾珠軸承)x 2Wooden borad(5”x10”) Wooden board(2”x10”)Copper wire(漆皮銅線) Chopstick(筷子) x 3Water bottle(水樽)Magnet (磁石)x 4LED 燈x 1CD case x 1),Making Process-製作過程,1. Preparing the material,Making Process-製作過程,2.making the frame(骨架) and base,1,2,3,Making Process-製作過程,Finished product,Making Process-製作過程,3.
5、Assembly(集合) the CD case and the base,1,2,3,4,Making Process-製作過程,4. making the coil by the copper wire,Making Process-製作過程,5. assembly to the CD case,Making Process-製作過程,5. assembly to the CD case,Making Process-製作過程,6. making the rotor(轉片),Making Process-製作過程,6. making the rotor (轉片),1,3,2,Making
6、Process-製作過程,7. making the turbine(渦輪),1,2,4,3,Making Process-製作過程,7. making the turbine (渦輪),5,6,7,Making Process-製作過程,8. assembly all the component(部件),Final Product-製成品,Finish!,Calculation相關計算,Power(功率) of Wind turbine,kinetic energy of a mass in motions is:The power in the wind is given by the r
7、ate of change of energy:As mass flow rate is given by:,Power (功率) of Wind turbine,Also, the rate of change of distance is given by:we get:Hence, the power can be defined as:,Power (功率) of Wind turbine,Power coefficient(功率系數),Cpmax = 0.59 Therefore, the extractable power:,Picture captured from http:/
8、www.eoearth.org/article/Betz,_Albert,German physicist Albert Betz,No wind turbine can convert(轉換) more than 16/27 (59.3%) of the kinetic energy of the wind into mechanical energy turning a rotor.,Power (功率) of Wind turbine,For this turbine,假設 ,Power Coefficient(功率系數), Cp = 0.5Air density(密度), = 1.23
9、 kg/m3Area of blades(扇葉), A= 0.04*0.2 = 0.008 m2Wind speed(風速), v = 20km/h = 5.56 m/sec所以, P = *0.5*1.23*0.008*5.563 = 0.423 W,Induced voltage-感生電壓,Since, Thus,Induced voltage-感生電壓,Normally, an AA battery(電池) is having 1.5V,Applications(應用),Factor (影響因素),Factor(影響因素) of output voltage:Wind speed(風速)Strength of magnet(磁石強度)*The number of turns of coil, N(線圈圈數)*Internal resistance of wire, r(電線內阻)Since因為 N-r,Iout,延伸探究,內阻同圈數對於輸出電流的連帶關係計算輸出功率計算效率,Demonstration-演示,完,
