The tip clearance of the turbine blade leads to the leakage of the working fluid

which increases the flow loss of the cascade. In order to reduce the cascade flow loss and improve the turbine efficiency

this paper takes the 1.5-stage Lisa turbine as the research object

and uses the orthogonal optimization method to explore the flow characteristics of the blade tip groove coupling jet structure by means of numerical simulation. The control mechanism of the tip structure on the leakage flow and its influence on the turbine efficiency are analyzed. Finally

an optimal turbine rotor blade tip groove coupling side wall jet structure is obtained

that is

a groove is set at the rotor blade tip and an equal spacing jet hole is opened on the pressure side ( PS ) side wall. The results show that compared with the traditional groove coupling spanwise jet method

the total jet flow required for the groove coupling side wall jet is reduced by 90 %

the leakage flow is reduced by 3.9 %

and the turbine efficiency is increased compared with other traditional control methods. Significantly

compared with the original turbine efficiency increased by 1.55 %.