Performance enhancement of industrial high loaded gas compressor using Coanda jet flap

Abstract An industrial highly loaded gas compressor with the large turning angles in gas turbines always causes the serious flow separations, which leads to the significant increase in aerodynamic losses and the evident deterioration of the pressure rise ability. In order to solve this issue, a novel active flow control technique inspired by the Coanda effect is introduced in this study. Here, the Zierke & Deutsch airfoil with the camber angle of 65° is selected for the reference profile of the highly loaded compressor cascade. Design of Experiment (DOE) is firstly used to obtain the sensitivity information of the geometric parameters in building the Coanda jet flap. The cascade shape with the optimal aerodynamic performance is then figured out based on the optimization method. The comparison of the flow details between the optimization result and the prototype is performed to further understand the flow mechanisms behind the performance enhancement. Finally, the experimental measurements are conducted to validate the effectiveness of the well-designed Coanda jet flap in the wind tunnel. The numerical and experimental results show that the Coanda jet can effectively improve the aerodynamic performance of the highly loaded cascade. A tradeoff exists between the increased mixing losses near the slot and the decreased shearing effects near the trailing edge when the mass flow rate of the Coanda jet is increased. The total pressure losses can be reduced by up to 18.4% when the normalized mass flow rate of the jet flow is equal to 1%. Meanwhile, the static pressure rise coefficient can be increased by 8.8% when the mass flow rate of the Coanda jet is equal to 1.5%.