Experiment on pressure distribution and flow resistance characteristics of internal lamilloy.

Two kinds of lamilloy models with different percentages of film hole opening were experimentally studied at the Reynolds numbers of 1×104-6×104,target surface, impingement surface and pressure coefficients of pinfins surface,local and total loss coefficients of impingement jet, arounding flow,effusion were experimented to explore the mechanism of flow loss. Results showed that,the pressure distributions were characterized by the second maximum value because of the transition from an accelerating stagnation region flow to a decelerating wall jet. The low pressure coefficients on the target and impingement surfaces were caused by the sink of two jets and the backflow, respectively. The pressure coefficients distributions on two rows of pinfins relatively far away from the impingement hole were significantly affected by Reynolds numbers. At the Reynolds number less than or equal to 3×104, the pressure distributions were similar with flow across cylinder. At the Reynolds number greater than or equal to 4×104, it also had characteristics of backflow. The effusion loss coefficients were biggest, the impingement jet loss coefficients were smallest and the arounding flow loss coefficients were moderate. As the percentages of opening decreased one half, the effusion loss coefficients of film holes increased at least 4 times while the loss coefficients of impingement jet loss and arounding flow had slight changes.