A one-way three dimensional gas-solid coupled design method was proposed to obtain the optimized performance blade profile at the design point. The original thermal state blade profile (denoted as RT) designed by the aerodynamics was used for calculating the flow field characteristics and deformation through one way coupled method. Then two revised cold state blade profiles with and without casing treatment (denoted as RC and RC-tip) through an area-averaged 3D interpolation modeling method were obtained. Results indicated that the flow rate of RC-tip impeller at choke point improved 1.93% under designed speed. The minimum blade loading also dropped by 30%. At low speed

performance of RC-tip was obviously better than that of RT

proving that the coupled design method optimized the blade loading and flow capacity of oblique impeller.