Lee, I-ChienI-ChienLeeChang, Yun-ChungYun-ChungChangDing, Pei-PeiPei-PeiDingChen, Ping-HeiPing-HeiChen2008-10-282018-06-282008-10-282018-06-28200502533839http://ntur.lib.ntu.edu.tw//handle/246246/85697https://www.scopus.com/inward/record.uri?eid=2-s2.0-25144463667&doi=10.1080%2f02533839.2005.9671053&partnerID=40&md5=8768f1d698da5d42ef4d3d9c96700d5bExperimental results of film cooling effectiveness over a concave surface with two staggered rows are presented by employing transient liquid crystal thermography. Four different discrete hole configurations are used for the injection of jet flow, including a straight circular hole configuration with a spanwise injection angle (β) of 0° and three forward-expanded hole configurations with β = 0°, 45° and 90° respectively. In all test models there are two staggered rows of discrete holes with streamwise injection angle (γ) of 35°. Blowing ratios (M) are 0.5, 1.0, and 2.0. The effects of blowing ratio, hole expanded angle, and injection angle orientation on film cooling performance are investigated. The jet flow with M = 0.5 is fairly uniform along the wall surface. The lift-off phenomenon can be found in the jet flow with β = 0° for both cases of simple and compound angles at M = 1.0 and also exists among all test cases at M = 2.0 except for β = 90°. The lift-off effect results in a decrease in both η and h /h0. At β = 0°, the jet flow with a forward-expanded hole gives higher η and lower h /h0 than a simple angle hole. At a fixed blowing ratio, the jet flow with compound angle holes has lower q /q0 and thus provides better wall protection than that with simple angle holes. In the present study, the compound angle with β = 0° at M = 2.0 provides the best film-cooling protection over the concave surface among all the test configurations. © 2005, Taylor & Francis Group, LLC.application/pdf962950 bytesapplication/pdfen-USCompound angle; Concave surface; Film coolingBlow molding; Flow of fluids; Jets; Liquid crystals; Thermography (temperature measurement); Thin films; Compound angle; Concave surface; Film cooling; Hole configuration; Cooling systemsjournal article10.1080/02533839.2005.96710532-s2.0-25144463667http://ntur.lib.ntu.edu.tw/bitstream/246246/85697/1/06.pdf