Blade Element Momentum Simulation

Hi, I have been trying to implement the well known Blade Element Momentum theory into Matlab for the analysis of a marine current turbine blade for my masters degree dissertation. However, I am still relatively inexperienced at Matlab and am experiencing many problems. This theory consists of finding the power coefficient at several intervals along the blade and summing them to find the overall power curve. Would there be an easy way of prompting the user to enter all the relevant data rather than asking 45 questions? Also can anyone recommend how I could solve this problem in matrix form. Any help or general comments on my code would be greatly appreciated. I have attached my Matlab code here.

clc clear

R=0.4; % Radius of Rotor B=3; % Number of blades V=2; % Fluid velocity Rho=998; % Fluid Density N=9; % Number of Blade Elements Cp_estimate=0.5; % Estimate power coefficient Alpha_design=4; % Design alpha Cl_design=1.04; % Design lift coefficient Cp=0;

R1=input(' please enter radius length 1? '); R2=input(' please enter radius length 2? '); R3=input(' please enter radius length 3? '); R4=input(' please enter radius length 4? '); R5=input(' please enter radius length 5? '); R6=input(' please enter radius length 6? '); R7=input(' please enter radius length 7? '); R8=input(' please enter radius length 8? '); R9=input(' please enter radius length 9? ');

C1=input(' please enter chord length 1? '); C2=input(' please enter chord length 2? '); C3=input(' please enter chord length 3? '); C4=input(' please enter chord length 4? '); C5=input(' please enter chord length 5? '); C6=input(' please enter chord length 6? '); C7=input(' please enter chord length 7? '); C8=input(' please enter chord length 8? '); C9=input(' please enter chord length 9? ');

P1=input(' please enter pitch angle 1? '); P2=input(' please enter pitch angle 2? '); P3=input(' please enter pitch angle 3? '); P4=input(' please enter pitch angle 4? '); P5=input(' please enter pitch angle 5? '); P6=input(' please enter pitch angle 6? '); P7=input(' please enter pitch angle 7? '); P8=input(' please enter pitch angle 8? '); P9=input(' please enter pitch angle 9? ');

Cl_1=input(' please enter lift coefficient at point 1? '); Cl_2=input(' please enter lift coefficient at point 2? '); Cl_3=input(' please enter lift coefficient at point 3? '); Cl_4=input(' please enter lift coefficient at point 4? '); Cl_5=input(' please enter lift coefficient at point 5? '); Cl_6=input(' please enter lift coefficient at point 6? '); Cl_7=input(' please enter lift coefficient at point 7? '); Cl_8=input(' please enter lift coefficient at point 8? '); Cl_9=input(' please enter lift coefficient at point 9? ');

Cd_1=input(' please enter drag coefficient at point 1? '); Cd_2=input(' please enter drag coefficient at point 2? '); Cd_3=input(' please enter drag coefficient at point 3? '); Cd_4=input(' please enter drag coefficient at point 4? '); Cd_5=input(' please enter drag coefficient at point 5? '); Cd_6=input(' please enter drag coefficient at point 6? '); Cd_7=input(' please enter drag coefficient at point 7? '); Cd_8=input(' please enter drag coefficient at point 8? '); Cd_9=input(' please enter drag coefficient at point 9? ');

while Cp>0

    while aplha>0

TSR= 4:1:10; % TSR from 4 to 10

TSR_local=TSR*(r_i/R); % Local Tip Speed Ratio Phi=(2/3)*arctan(1/TSR_local); % Angla of Relative Fluid C=((8*3.14*r_i)/(B*Cl_design))*(1-cos(Phi));

F=(2/3.14)*ACos(exp(-(((B/2)*(1-(r_i/R)))/((r_i/R)*sin(Phi))))); % Tip Loss Factor

C_T=(sigma*((1-alpha)^2)*((C_l*cos(Phi))+(C_d*sin(Phi))))/((sin(Phi))^2);

if C_T<0.96 alpha=1/(1+(4*F*sin(Phi))/(sigma*C_l*cos(Phi)));

else alpha=1/(((4*F*cos(Phi))/(sigma*C_l))-1);

end if

    end
end

figure(1) plot(store_Cp,store_TSR) Title('Cp vs Tip Speed Ratio') Xlabel('TSR') Ylabel('Cp')

Best Regards, Kevin

Answer 1

[hamed rahimi]

how i can power curve by blade element momentum in matlab?