A Transient Method Using Liquid Crystal for Film Cooling Over a Convex surface

[摘要] In order to explore the effect of blowing ratio on film cooling over a convex surface, the present study adopts the transient liquid crystal thermography for the film coolingmeasurement on a straight circular hole configuration. The test piece has a strength ofcurvature(2r/D)of 92.5, pitch to diameter ratio(P/D)of 3 and streamwise injectionangle(γ)of35∘All measurements were conducted under the mainstream Reynoldsnumber(Red)of 1700 with turbulence intensity(Tu)of 3.8%, and the density ratio between coolant and mainstream(ρc/ρm)is 0.98. In current study, the effect of blowingratio(M)on film cooling performance is investigated by varying the range of blowingratio from 0.5 to 2.0. Two transient tests of different injection flow temperature wereconducted to obtain both detailed heat transfer coefficient and film cooling effectivenessdistributions of measured region. The present measured results show that both thespanwise averaged heat transfer coefficient and film cooling effectiveness increase withdecreased blowing ratio.

[学科分类] 力学，机械学