Aerodynamic modification and optimization of intermediate pressure compressor in marine intercooled recuperated gas turbine

The intercooling recuperated cycle (ICR) is commonly employed in marine gas turbines to enhance thermal efficiency. However, the addition of an intercooler may lead to the increased dimension and structural complexity of marine ICR gas turbines. To address this issue, we propose an improved configuration of the intermediate pressure compressor – an axial-centrifugal combined compressor (ACC) with high inlet hub-tip ratio and high flow rate. The aerodynamic performance of the ACC at multi-operating points is optimized via an improved free-form deformation method for the parametric modeling of the flow paths and blades of turbomachinery. The result indicates that the number of stages decreases from 6 to 3 and the axial length is reduced by 38.3% after modification. The adiabatic efficiency of the optimized ACC at the design and low-speed operating points is improved by 1.18% and 6.48% respectively. Additionally, the ACC redesigned scheme can reduce the axial length, maximize the flow path space utilization, enhance the stage load capacity, and significantly improve the low-speed performance. This provides a reference for developing advanced marine ICR gas turbines with high power and low fuel consumption.