Experimental investigation on flow and heat transfer instabilities of RP-3 aviation kerosene in a vertical miniature tube under supercritical pressures

Abstract

This paper presents experimental investigations on flow and heat transfer instabilities of RP-3 aviation kerosene under supercritical pressures in a vertical tube with inner diameter of 2 mm. The flow changes from laminar to the transition regime as the fuel is heated, which resulted from decrease of fluid density and increase of velocity. A 13-component surrogate model of RP-3 aviation kerosene is used to calculate the thermophysical properties of fuel. Under large wall heat flux conditions, instabilities in flow and heat transfer are observed when the inner wall temperature and outlet fluid temperature approach the pseudo-critical temperature, respectively. The former is accompanied with enhancement in heat transfer and could be explained by the pseudo-boiling mechanisms. Thermally-induced pressure oscillations due to drastic density variation is found to be the reason for the latter case. The effects of inlet pressure, wall heat flux and inlet Reynolds number on flow and heat transfer instabilities are also studied. It is found that higher inlet pressures and heat fluxes can weaken the flow instabilities. The influence of inlet Reynolds number is more complicated, different types of flow instabilities could be observed with the increase of inlet Reynolds number. In addition, stability boundaries are obtained based on the experiments data, which could be used to quantitatively predict the occurrence of flow and heat transfer instabilities.