Studies on a Diagonal-Flow Airfoil Fan with Low Loading : 1st Report, Effects of Aspect Ratio and Solidity

Abstract

In order to improve the performance of a diagonal-flow fan with low loading, effects of solidity and aspect ratio of the rotor blading have been investigated experimentally. It is shown that with a decreasing aspect ratio, the effective operating range expands remarkably into the region of the lower flow rates, and the total pressure and efficiency increase there. With an increasing solidity, the total pressure increases with the stalling flow coefficient changing little, hence a dip in the performance characteristics becomes deeper. From the viewpoint of stable operation, lower aspect ratio and lower solidity are desirable. In addition, the validity of the present design method, which has been derived and extended from that of highly-loaded diagonal-flow fans, is confirmed.