Figure 13 Comparison of maximum power coefficient w ih solidity for blade numbers=3,5 and 7, with blade pitch angle (ß) as parameter.
For B= 7 & B=5, the maximum power coefficient obtained between solidity range of 0.05 to 0.12.
While for B=3 the maximum power coefficient obtained in the solidity range of 0.03 to 0.05 at the operating pitch angel equal to 30.
If solidity is increased from 3% to 7% the gain in the value of maximum power coefficient is 16% for all cases.
For B=3, the value of maximum power coefficient decreases as the solidity increases from 0.1 to 0.14.
Maximum power coefficient is observed to be decreasing between the solidity ranging from 0.03 to 0.05.
Beyond solidity of 0.06, Cpmax is insensitive to the pitch angle for blade number 5 and 7.
10.4 Effect of solidity on tip speed ratio at maximum power coefficient.
Figure 14 shows that the relationship between tip speed ratio at maximum Cp and solidity, at pitch angle =3°.
For solidity 0.05, Tip speed ratio at maximum Cp was between 5 and 7 for B 3 while, B=5 and B=7.
As solidity increases, tip speed ratio at maximum Cp decreases in all cases at approximately the same rate.