| The combustion chamber wall of scramjet has been facing severe working environment with high temperature,which influence the performance of the engine seriously.Regenerative cooling technology is an active cooling scheme to solve this problem.The thermophysical properties of the three-component surrogate model for kerosene fuel RP-3 in supercritical pressure state were analyzed.The flow and heat transfer characteristics of RP-3 in circular pipe and rectangular channel were numerically simulated.Effects of the shape,the ratio of distance to height and the height of the artificial roughness element,together with the aspect ratios of the rectangular channel on the heat transfer process of RP-3 under supercritical pressure were investigated.It is found that the thermophysical properties predicted by the three component surrogate fuel model for RP-3 are in good agreement with the experimental data.But it is hard to predict the thermal properties of all kinds of surrogate fuel model for aviation kerosene RP-3 at high temperature precisely.In order to simulate the thermal physical parameters of RP-3 aviation kerosene accurately,the pyrolysis of the large molecules in the real aviation kerosene should be taken into account.To better predict the critical temperature of RP-3,the molar mass of alternative fuels should be as close as possible to the molar mass of real RP-3.Compared with the rectangular and trapezoidal rough element,the triangular roughness element can decrease the temperature of the heated wall surface significantly.At the artificial roughness height of 0.1 mm,and the ratio of distance to the height of 5 for the pipe channel and 10 for the rectangular channel,the roughness element can not only ensure the full development of the vortex near the wall,but can disturb the fluid behind the rough element in time as well.Reasonable arrangement of aspect ratio of the rectangular channel can also significantly enhance convective heat transfer between RP-3 and the heated wall. |
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