Experimental investigation on discharge coefficient of film holes in a longitudinal ripple insulated liner

For a longitudinal ripple insulated liner with discrete film holes in high-powered aircraft engine,the discharge coefficients of the film holes in different positions of the ripple liner were investigated.The discharge coefficients of coolant injection were obtained in a region of Reynolds number Re_c=24×10⁴～33×10⁴,and blowing ratio S=0.02～0.07.The results show:(1)The discharge coefficients differ greatly at various hole array positions.(2) For the hole with a low length-to-diameter ratio(L/D≈0.17) in the same position,the momentum ratio of the hole to secondary fluid has an important influence on the discharge coefficients Cd,especially in the case of small momentum ratio,while the Reynolds number of film hole and secondary flow has little influence on the discharge coefficients Cd.