Research Of Flow And Heat Transfer Characteristics Of Kerosene-Water Mixture In Microchannel Under Supercritical Pressure And Enhancement Technology

In this paper,experiments are combined with theoretical analysis to systematically study the flow and heat transfer characteristics of kerosene-water mixture microchannels under supercritical pressure,and use numerical simulation to explore the strengthening effect of parallel micro-ribs on supercritical kerosene flow and heat transfer.Compared with pure aviation kerosene,the kerosene-water mixture with higher specific heat has a better cooling effect on the engine,but the phase change occurs when the water reaches the saturation temperature,which affects the flow and heat transfer characteristics of the kerosene-water mixture.The effect of different water content on the flow and heat transfer of kerosene-water mixtures under supercritical pressure was experimentally studied,and the flow and heat transfer of pure kerosene under supercritical pressure were compared.When the temperature of the kerosene-water mixture in the pipeline under supercritical pressure is higher than the saturation temperature of the water under the current pressure,the temperature of the test tube will rise sharply,and the heat transfer will deteriorate.The flow heat transfer of aviation kerosene under supercritical pressure is relatively stable,and there will be no deterioration of heat transfer in the studied temperature range.The higher the water content of the kerosene-water mixture,the higher the overall heat flux density and convective heat transfer coefficient,and the earlier the heat transfer deterioration phenomenon appears.On the basis of the experimental results,comprehensively considering the physical properties of water and aviation kerosene,the influence of water content on the flow and heat transfer of the kerosene-water mixture is analyzed.The influence of mass flow,pressure and heat flux density on the flow and heat transfer characteristics of kerosene-water mixtures under supercritical pressure was studied by changing the experimental conditions.For kerosene-water mixtures,the greater the mass flow rate,the higher the overall convective heat transfer coefficient and the more obvious heat transfer deterioration.When the deterioration of heat transfer disappears,it is affected by the gaseous water in the mainstream,and the higher the pressure,the higher the convective heat transfer coefficient of the kerosene-water mixture.The overall convective heat transfer coefficient of the kerosene-water mixture increases with the increase of the heat flux density,and the deterioration of heat transfer will occur sooner.For the flow and heat transfer of aviation kerosene in the micro-ribs rectangular cooling channel under supercritical pressure,a three-dimensional numerical simulation study of fluid/solid/thermal coupling is carried out.Considering the characteristics of kerosene physical properties changing drastically with temperature under supercritical pressure,the influence of the distribution position of parallel micro-ribs in the rectangular channel and the inclination angle of the ribs on the flow and heat transfer characteristics of supercritical kerosene is analyzed.The results show that the micro-ribs can enhance the flow and heat transfer between the hydrocarbon fuel and the cooling channel,and reasonably changing the position of the parallel micro-ribs in the cooling channel can improve the heat transfer enhancement effect of the micro-ribs.