Experimental investigation on convection heat transfer of supercritical hydrocarbon fuel in a long mini tube

Abstract

Thermal management system is crucial for hypersonic vehicles, in which a large amount of thermal energy due to aerodynamic heating needs to be removed by hydrocarbon fuel. In this study, an experimental investigation is performed on the convection heat transfer of supercritical hydrocarbon fuel in a long mini tube. The horizontal test tube has an inner diameter of 1.0 mm and a length-to-diameter ratio of 980, which are close to those of practical heat-transfer channels in the thermal management system for hypersonic vehicles. The non-linear distribution characteristics of wall temperature and heat transfer coefficient along the test tube are presented. The heat transfer regions of hydrocarbon fuel are classified into initial heat transfer (IHT), normal heat transfer (NHT), enhanced heat transfer (EHT) and deteriorated heat transfer (DHT). The heat transfer mechanisms in each heat transfer region are discussed in detail. The heat transfer of hydrocarbon fuel are affected by the dramatic variations in thermo-physical properties and buoyancy effect. Heat transfer is commonly deteriorated under disadvantageous thermo-physical properties and absence of buoyancy effect. The results could be beneficial for the analysis and design of the thermal management system for hypersonic vehicles.