Experimental Study On Heat Transfer Characteristics To Supercritical Hydrocarbon Fuel In A Horizontal Micro-Tube

Supercritical hydrocarbon fuel experimental loop was constructed at Beihang University to study the heat transfer characteristics to supercritical hydrocarbon fuel. The test section, a stainless tube (1.86mm I.D., 2.26mm O.D., 1Cr18Ni9Ti) with the length of 300mm, was placed horizontally above the ground and the local heat transfer coefficients of the test section were systematically measured at fixed supercritical pressure of 5MPa. The mass flux varied from 786.5 to 1573 kg/ (m(2).s), with the uniform heat flux from 180 to 450kW/m(2) and the inlet fuel temperature ranged from 373 to 673K.The experimental investigation was confined to supercritical flows with heat addition only. Hence, heat losses were measured to be taken into consideration for every experimental condition. The experimental results were analyzed that heat transfer enhances at the reduced temperature T-b/T-pc rising from 0.95 to 1.04 and deteriorates when Tb/Tpc is larger than 1.04. The criterions of Shitman and Jackson were selected to judge the heat transfer characteristics in a horizontal microtube. The results indicated that buoyancy effects are ignored as the K<0.01 for the micro-scale tube and thermal acceleration is the main factor for the heat transfer characteristics. By direct comparison with an assortment of experimental data, a new correlation was proposed to be more accurate than others in predicting heat transfer phenomena for Chinese RP-3 hydrocarbon fuel in a horizontal micro-tube.