Fast multi-objective optimization design of gas turbine L-inlet duct

Abstract

With ever-increasing demand for high efficiency and high stability gas turbine under the goal of carbon neutrality, the design of L-inlet duct has set stricter demands for low pressure loss and low flow distortion. No general optimization guidelines on both pressure loss and distortion for L-inlet duct were found in open literature. Four geometry parameters including inlet width, inlet length, contraction geometry angle and truncated cone geometry angle are explored for their effects on the trends of pressure loss and flow distortion. Optimization geometry parameters of the L-inlet duct are analysed, and the flow characteristics are thoroughly examined. The flow field characteristic of ΔP_t, DC60, SC60 from surrogate model are validated by CFD, the relative errors are 0.37%, −3.92% and 1.75%, respectively. At the design point EF = 35 comparing with original scheme of the L-inlet duct, ΔP_t decreases 21.14%, DC60 decreases 45.37%, and SC60 decreases 38.7%. For all off design conditions, the optimization results are better than original scheme. It is estimated that gas turbines can achieve a 0.144% reduction in power loss and a 0.333% improvement in surge margin.