错排射流冲击受限短通道内流场的实验研究

用五孔针对简化后的涡轮叶片错排射流冲击受限短通道流场进行了详细的测量,着重研究受限通道内各截面的流动规律,以及射流孔错排布置、出流孔、通道高度比和射流雷诺数对通道流动特性的影响。实验结果表明:通道高度比的变化会显著改变通道内的流场结构;在同一高度比下,射流雷诺数变化对流场结构的影响很小;出流孔的抽吸作用使附近气流加速并在通道内出流孔位置形成一局部低速区;受错排射流诱导及冲击靶面后壁面射流反卷通道内形成漩涡,使高速气流向通道侧壁甚至孔板面集中,该结果有助于深入了解错排射流受限通道内冲击冷却的内在机理。

Flow Field Measurements in a Confined Channel with Staggered Jet Array Arrangement

Purpose.This experimental study is part of the research done under a contract supported by Rolls-Royce,plc.Research on understanding impingement cooling better in confined channel,the purpose of our experimental study,is rarely found in the open literature.In the full paper,we explain in detail the method of our experimental study;in this abstract,we just sketch an outline of our explanation.First,we explain our experimental set-up,which we use three figures in the full paper to describe:(1) Fig.1 shows the turbine blade containing the confined channel;(2) Fig.2 shows the test model with plenum inlet,three jet holes,and outlet hole;(3) Fig.3 shows the orifice plate with three staggered jet holes and outlet hole;it also shows the measurement cross-sections of the confined channel.Second,all we like to say in a sketch about our measurement methods is that a five-hole probe was used in our measurements.Important results of our research include:(1) flow distribution has an alternating feature along the main flow direction;(2) vortex was observed when the jet impinged on target wall and shrank with the increase of the aspect ratio of channel;the vortex pushed the high velocity flow to move toward side walls and orifice plate;these results are helpful to understanding the mechanism of heat transfer augmentation of impingement cooling in confined channel;(3) compared with the aspect ratio,the Reynolds number of the jet hole has only a small contribution to the flow transformation.