隔热结构对塞块式量热计热流测量的影响  

Effects of adiabatic structure on heat flux measurement using a slug calorimeter

作　　者：杨庆涛[1] 白菡尘[1] 张涛[2] 王辉[2] 

机构地区：[1]中国空气动力研究与发展中心超高速所高超声速冲压发动机技术重点实验室,四川绵阳621000 [2]中国空气动力研究与发展中心超高速所,四川绵阳621000

出　　处：《实验流体力学》2014年第5期92-98,共7页Journal of Experiments in Fluid Mechanics

基　　金：高超声速冲压发动机技术重点实验室开放课题(STSKFKT2012003)

摘　　要：塞块式量热计是热结构试验中常用的热流传感器,其侧向传热是测量误差的重要来源。在对塞块式量热计传热分析的基础上,设计了一种改进型隔热结构,并提出了一种基于半无限大体假定的热损失修正方法。通过建立塞块式量热计的有限元数值模型,分析了量热塞与隔热材料的接触热阻对数据处理结果的影响,在接触热阻较大时(R=1×10-3 m2·K/W),未修正时最大测量误差不超过-9%,而修正后最大误差超过了20%;在接触热阻较小时(R=1×10-4 m2·K/W),未修正时的最大测量误差约-20%,修正后则不大于1.5%。可见该修正方法只适用于接触热阻较小的情况。。数值模拟结果还表明,在隔热层表面附近增加金属尖楔的改进型结构,隔热材料最高温度从超过2000℃降低到300℃以下,有利于保护隔热材料不被烧损,间楔与传感器之间的换热面积只有总侧向面积的约2.9%,两者之间的换热几乎不影响数据处理方法的选择。Slug calorimeter is widely used in thermal protection tests, and lateral heat conduction is one of the most important sources of heat flux measurement error using a slug calorimeter. An improved adiabatic structure is designed based on slug calorimeter heat transfer analysis, and a heat loss correction method is proposed based on semi-infinite body assumption. FEA（Finite Element Analysis） model is developed to study effects of thermal contact resistance （TCR） between the slug and the adiabatic structure on data reduction results. If TCR is large （R= 1 × 10 3 m2 . K/W）, the max measurement error is less than -9 % without correction and more than 20% with correction. On the other hand, when TCR is small （R=I× 10-4m2 . K/W）, the error is about -20% without correction and less than 1. 5% with correction. It is concluded that the correction method can only used in the situation when TCR can be neglected. Numerical simula- tion results also show that using the improved structure with a metal sharp wedge structure add- ed near the surface of adiabatic layer, the max temperature of adiabatic material decreases from over 2000℃ to less than 300℃, which means that with the improved structure, the adiabatic material is protected efficientlly from ablation. The heat transfer area between the metal wedge and the slug is only about 2.9 % of the total lateral area, which hardly effects selection of data reduc tion methods.

关 键 词：塞块式量热计 侧向传热 热损失修正 隔热结构 热流测量 

分 类 号：V441[航空宇航科学与技术—飞行器设计]