Influence of Solidity on Aerodynamic Performance of Axial Supersonic Through-Flow Fan Cascades

Abstract

To determine the effects of solidity on its aerodynamic performance and key flow structures, this study reports numerical simulations of the cascades of an axial supersonic through-flow fan with an inlet Mach number of 2.36 over a 15 deg range of incidence. The results indicate that, as the solidity increased, the overall loss first dropped and then increased. At the design incidence, loss at optimal solidity was 78% lower than the maximum loss. The overall loss was heavily dependent on the solidity but insensitive to incidence, especially at low solidity. At a critical solidity (2.38), the shock at the leading edge on the pressure side impinged on the suction surface near the trailing edge. At the optimal solidity, the wake loss was minimized and the number of reflected shocks decreased. The wake loss can be reduced by causing the shock to impinge on the suction surface near the throat of the passage. Moreover, this shock loss can be controlled by weakening its intensity. While reducing the local separation induced by the shock/boundary-layer interaction is ineffective for simultaneously reducing the loss of viscosity, reducing the loss of friction dominated by the surface area of the blade per unit of mass flow is effective.