Experimental investigation on the combined cooling methods of jet impingement and film cooling for the pressure surface of the turbine vane leading cavity

To investigate the performance of impingement/film combined cooling methods on the turbine vane pressure surface of leading cavity, typical cooling techniques and potential configurations were designed. The conjugate heat transfer experiments were carried out. Four different vanes were tested in the experiments, including Vane 0 (typical film cooling without jets), Vane 1 (typical impingement/film cooling with centerline normal jets), Vane 2 (impingement/film cooling with offset jets), and Vane 3 (impingement/film cooling with staggered offset jets). The effects of impingement hole position, BR (blowing ratio), and TR (temperature ratio of mainstream and coolant) were investigated. The experimental results show that the turbine vane cooling characteristics were determined by internal cooling, external cooling, vane heat conduction and coolant parameters jointly. Jet impingement, BR increase and TR increase can enhance the cooling performance. Compared with Vane 0, the overall-averaged ICE (integrated cooling effectiveness) of Vanes 1, 2, and 3 increased by 1.95 %-8.75 %. Due to the offset of the impingement hole, the jet impingement enhanced heat transfer region of Vane 2 was relatively independent of the gas film coverage region, the ICE of Vane 2 was more uniform and greater. With increasing of blowing ratio and temperature ratio, the ICE gradually increased, but the growth rate gradually decreased. Four alternative cooling structures for the pressure surface of leading cavity were tested at different working conditions and the experimental results can be used to support the design of the cooling structure for the turbine vanes.