Experimetal Study Of The Flow Field Over Flat Plate With Cooling Holes

With the increase of inlet gas temperature, the investigation of cooling technique for the turbine blade is interested by more and more researchers. High-temperature will lead the turbine componet heat load and mechanical load increased. Effective cooling technology becomes a very urgent requirment, to ensure the life of the machine. The film cooling technique is used widely for the turbine blade and the flow fild. Based on the secondary flow mechanism through bending channel, proposed a curved cooling holes to improve cooling efficiency downstream of the the cooling hole. Recently, particle image velocimetry(PIV) and liquid crystal technique has no effect on the flow filed, accurate measurement of flow rate and temperature, which is widely usde in jet-crossflow problem.In order to have an insight into the flow structure nearby cooling holes. First, the second-dimensionan flow field at different reynolds number(480,1000) and different blowing ratios in plate are measured with PIV. The holes are circular in either straight or curved with an angle of90°. The center and four cross section are investigated, compared with the CFD simulation results. Experimental results show that curved hole has a lower jet trajectory, can enhance the film cooling effective. The other hand, the curved jet with high transverse hole expansion ability to improve the coverage of lateral effect. Then, the experimental of heat transfer performance downstream of the cooling hole in a flat plate with positive streamwise pressure gradients(K=2.5×10-6)). The holes are circular in either straight or curved with an angle of90°. Detailed measurements of adiabatic effective at different blowing ratio, between0.5and1, for a single hole were presented using a steady state technique with wide band Thermo-chromic Liquid Crystals(TLC). The experiments results show that the high cooling efficiency and the regional cooling effectiveness downstream of curved cooling hole are on both sides of the hole. Straight hole has similar distribution but only a small blowing ratio. Which is similar distribution with no pressure gradient. From the numerical point, the pressure gradient will decrease with the effect of the positive pressure gradiant.