平板气膜传热系数液晶稳态测量中固体导热对其精度和效率的影响  

Effect of Solid Heat Conduction on Accuracy and Efficiency in Steady-state Liquid-crystal Measurement of Flat Gas Film Heat Transfer Coefficient

作　　者：薛启超 郜鸿宇 李雪英 任静 Qi-chao;Xue Hong-yu;Gao Xue-ying;Li Jing Ren(Department of Energy and Power Engineering,Tsinghua University)

机构地区：[1]Department of Energy and Power Engineering,Tsinghua University

出　　处：《风机技术》2021年第5期1-7,I0006,共8页Chinese Journal of Turbomachinery

基　　金：National Science and Technology Major Project(2017-111-0009-0035)。

摘　　要：气膜冷却是一种应用广泛且有效的透平冷却方式。传热系数是气膜冷却的主要特征物理量之一,直接影响到热端部件的壁面温度。发展气膜冷却传热系数的高精度、高效率测量方法对气膜冷却特性的研究和冷却设计具有重要意义。本文针对平板气膜冷却传热系数稳态测量方法,通过雷诺时均(RANS)数值模拟,研究了平板背部固体导热损失对传热系数测量结果精度和测量过程效率的影响机制。研究表明,背部保温材料的厚度直接影响到平板背部固体导热过程,进一步导致对于测试结果精度和系统达到稳态的时间(即测量效率)的影响;对于某个特定的气膜传热系数测量实验来说,存在着一个“最佳”的保温材料厚度范围。在此基础上,本文提出了进一步兼顾平板气膜冷却传热系数稳态测量精度与效率的方法。Film cooling is an effective and widely used cooling method in industrial turbine.The heat transfer coefficient is one of the main characteristic of film cooling,which directly affects the wall temperature of the hot end part.The development of high-precision and high-efficiency measurement methods for the heat transfer coefficient of the film cooling is of great significance for the study of gas film cooling characteristics and cooling design.In this paper,the steady-state measurement method of flat film cooling coefficient is studied.Through the numerical simulation of Reynolds time-averaged(RANS),the influence mechanism of solid heat loss on the accuracy of the heat transfer coefficient measurement and the efficiency of the measurement process is studied.It is shown that the thickness of the back insulation material directly affects the solid heat conduction process on the back of the plate,which further leads to the influence of the accuracy of the test results and the time when the system reaches steady state(ie,measurement efficiency).For a specific film heat transfer coefficient measurement experiment,there is a range of insulation thicknesses that performs well.Based on this observation,this paper proposes a method to further balance the steady state measurement accuracy and efficiency of the flat film cooling heat transfer coefficient.

关 键 词：传热系数 导热损失 气膜冷却 透平冷却 稳态测量 导热过程 保温材料 过程效率 

分 类 号：TK124[动力工程及工程热物理—工程热物理]