图书馆订阅: Guest
Begell Digital Portal Begell 数字图书馆 电子图书 期刊 参考文献及会议录 研究收集
流动显示和图像处理期刊
SJR: 0.161 SNIP: 0.312 CiteScore™: 0.1

ISSN 打印: 1065-3090
ISSN 在线: 1940-4336

流动显示和图像处理期刊

DOI: 10.1615/JFlowVisImageProc.v3.i2-3.20
pages 129-140

LOCAL HEAT TRANSFER COEFFICIENT AND FILM EFFECTIVENESS DISTRIBUTIONS ON A CYLINDRICAL LEADING EDGE MODEL USING A TRANSIENT LIQUID CRYSTAL IMAGE METHOD

Srinath V. Ekkad
Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, 27695-7910
Hui Du
Turbine Heat Transfer Laboratory, Department of Mechanical Engineering, Texas A&M University, College Station, Texas 77843-3123
Je-Chin Han
Turbine Heat Transfer Laboratory, Department of Mechanical Engineering, Texas A&M University College Sation, TX 77843-3123, USA

ABSTRACT

A transient liquid crystal technique is presented for measuring detailed heat transfer coefficients and film effectiveness on a cylindrical test model with film cooling. The technique uses a thin liquid crystal coating on the test surface and two similar transients tests. The cylinder, coated with a thin layer of liquid crystals, is heated to a uniform surface temperature and suddenly exposed to a cooler mainstream. The time history of color change at each pixel location is analyzed to obtain the local heat transfer coefficient and film effectiveness. Tests were run at a mainstream Reynolds number based on cylinder diameter of 100,900. The effect of blowing ratio on heat transfer coefficient and film effectiveness was studied for five blowing ratios ranging between 0.2 and 1.2. Two roles of holes at ±15° from stagnation and hole spacing of four-hole diameters apart and angled at 30° and 90° to the surface in the spanwise and streamwise directions were used for coolant ejection. Air was used as coolant. Detailed distributions obtained using the present technique provide a better understanding of the film cooling phenomena on the cylinder surface. The technique provides high resolution and more accurate results compared with classic heat transfer measurement techniques. Some of the results from the present study are compared with results obtained using classic heat transfer measurement methods.