浮升力对竖直上升圆管内超临界航空煤油换热的影响及评价准则  

Influence and Evaluation Criterion of Buoyancy on Heat Transfer of Supercritical Aviation Kerosene in a Vertical Upward Circular Tube

作　　者：王彦红 陆英楠 李素芬[2] 东明[2] WANG Yan-hong;LU Ying-nan;LI Su-fen;DONG Ming(School of Energy and Power Engineering,Northeast Electric Power University,Jilin 132012,China;School of Energy and Power Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]东北电力大学能源与动力工程学院,吉林吉林132012 [2]大连理工大学能源与动力学院,辽宁大连116024

出　　处：《推进技术》2021年第11期2546-2554,共9页Journal of Propulsion Technology

基　　金：国家自然科学基金(51576027)。

摘　　要：为深入理解航空发动机再生冷却热防护中的换热机理,对竖直上升圆管内超临界压力RP-3航空煤油的传热恶化开展了实验研究。探究了两类传热恶化的换热特征和形成机理,考察了热流密度、质量流量和进口压力对传热恶化的影响机制。获得了两类传热恶化的起始条件判别准则。以Nu/Nu0=0.75作为依据,建立了浮升力影响评价准则。通过格拉晓夫数修正实现了换热关联式预测。结果表明:两类传热恶化出现在不同条件下,低温区传热恶化源于边界层转捩和浮升力的综合作用,当进口雷诺数大于5730时其不再出现;高温区传热恶化的临界热流密度可以表述为质量流量的函数关系。当浮升力参数Grb/Re2.7和Gr/Re2分别大于10-7和10-3时,浮升力作用不可忽略。改进的换热关联式具有合理的预测精度,满足热防护系统设计的工程运用。To deeply understand the heat transfer mechanism in regenerative cooling thermal protection ofaero engine,an experimental investigation on heat transfer deterioration of RP-3 aviation kerosene in a verticalupward circular tube under supercritical pressures was conducted.The heat transfer characteristics and formationmechanisms of two types of heat transfer deterioration were studied,and the influence mechanisms of heat flux,mass flux and inlet pressure on heat transfer deterioration were investigated.Two criteria for determining the ini‐tial conditions of heat transfer deterioration were obtained.Based on Nu/Nu0=0.75,an evaluation criterion ofbuoyancy effect was established.The correlation prediction of heat transfer was achieved by the modification ofthe Grashof number.Results indicate that these two types of heat transfer deterioration occur at different conditions.The heat transfer deterioration in low temperature regions originate from the combined effect of the bound‐ary layer transition and the buoyancy,and it no longer appears when the inlet Reynolds number is higher than5730.The critical heat flux for heat transfer deterioration in high temperature regions can be expressed as a func‐tion of mass flux.When the buoyancy parameters Grb/Re2.7and Gr/Re2are higher than 10-7and 10-3,respectively,the buoyancy effect cannot be ignored.The modified heat transfer correlation has reasonable prediction accuracyand meets the engineering application of thermal protection system design.

关 键 词：航空发动机 热防护 再生冷却 传热传质 浮升力 评价准则 

分 类 号：V231.1[航空宇航科学与技术—航空宇航推进理论与工程]