Research On Convection Heat Transfer Of Supercritical Pressure Hydrocarbon Fuel Under Low Rotation Speed

The internal blade surface temperature of turbine Engine and TBCC has exceeded2000K.It is a new and efficient method to cool the rotating blades through supercritical pressure hydrocarbon fuel.The heat transfer characteristics of supercritical pressure fluids under rotating conditions have high academic value and practical significance.Based on the previous researches of convection heat transfer of supercritical hydrocarbon fuel in the medium and high rotating tube,this paper studied the convection heat transfer of supercritical pressure n-decane in low-speed rotating tube,and revealed the influence of different conditions on the heat transfer.This study is instructive for the design of subsequent turbine blades cooling systems.In this paper,the convection heat transfer phenomena of supercritical pressure n-decane in rotating tube are studied.The experimental variables include rotation speed,mass flow,heat flux,pressure,etc.The experimental objects are the centrifugal,horizontal and centripetal section of the U-shaped tube.And the results show:For the centrifugal section,the convection heat transfer increases with the rotation speed,the heat transfer coefficient at 500 rpm is 1.5-2 times that at 50 rpm,and the trailing edge is stronger than the leading edge;When the tube is at low rotation speed,the wall temperature and convection heat transfer is similar to those of static tube.On the other hand,the high rotation speed can enhance the heat transfer and reduce the length of inlet section.Compared with the stationary condition,the heat transfer deterioration exists when Bo_?^* is below 0.8×10^-4,which represents the strength of buoyancy,otherwise the buoyancy effect leads to the heat transfer enhancement.The greater the heat flux,the more severe the heat transfer deterioration,and the more obvious the recovery and strengthening of the heat transfer in the tube.The greater the mass flow and the closer the pressure is to the critical pressure,the greater the convective heat transfer.For the horizontal section,the convection heat transfer increases with the rotation speed,the heat transfer coefficient at 500 rpm is 1.5-2 times that at 50 rpm,and there is no significant difference between trailing edge and leading edge,however in somewhere the heat transfer in leading edge is greater than trailing edge.Similar to the centrifugal section,the high rotation speed can enhance the heat transfer and reduce the length of inlet section,which make the convection heat transfer increase along the tube.Compared with the stationary condition,the heat transfer deterioration exists when Bo_?^* is below 10^-4,and the heat transfer enhancement exists when that is above 10^-4.The effects of heat flux,mass flow,channel pressure,is similar to the centrifugal section.For the centripetal section,the convection heat transfer increases with the rotation speed,the heat transfer coefficient at 500 rpm is 1.5-2.5 times that at 50 rpm,and there is no significant difference between trailing and leading edges.And the high rotation speed can enhance the heat transfer and reduce the length of inlet section.Compared with the stationary condition,heat transfer deterioration exists when Bo_?^* is below 10^-4,otherwise the buoyancy effect leads to the heat transfer enhancement in the tube.In addition,the greater mass flow rate in the centripetal section,the smaller convection heat transfer coefficient,and the greater heat transfer deterioration relative to the stationary conditions.The effect of heat flux and channel pressure is similar to that of the centrifugal section.In addition,the greater the mass flow,the smaller the coefficient of heat transfer.