| The double outlet hole is a novel film hole, which has a good performance of filmcooling. The discharge coefficients and film cooling effectiveness of double outlet holeinjection on a flat plate is measured experimentally. In addition, the film cooling effectivenessof double outlet hole injection on the surface of the turbine blade is also studied byexperiment and numerical simulation.Six different types of geometry sturcture of film hole is supplied in the experiment of thedouble outlet hole injecting on a flat plate. Under the condition of different blowing ratios andRenold numbers, the discharge coefficients and film cooling effectiveness of six differenttypes of film hole is measured. The key findings may be summarized as follows:(1) Thedischarge coefficients increase with the blowing ratios increasing.(2) At the low blowingratios，the Renold numbers have a weak influence on the discharge coefficients. With theblowing ratio increasing, the discharge coefficients increase weakly with Renold numbersincreasing.(3) Film cooling effectiveness decrease at low blowing ratios with the X/Dincreasing, but at the high blowing ratios, with the X/D increasing, the film coolingeffectiveness have a complicated variation of first decreasing, then increasing and thendecreasing.(4) Based on the film cooling effectiveness, the best structure of double outlethole is the film hole of branch hole with45degree of oritention angle.At the blowing ratio of1.0,1.5and2.0, the film cooling effectiveness on the surface ofturbine blade is studied experimentally. The key findings may be summarized as follows:(1)On the suction side, the coolant from the double outlet hole attach the surface well. At thelow blowing ratios, the coolant cover the sueface uniform.(2) On the pressur side, thecoolant from the film hole has a bad attachement to the surface nearby the outlets of filmhole. The blowing ratio is increased, which have a benefit of increasing the film coolingeffectiveness. |
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