RP-3 is a kind of aviation kerosene commonly used in hypersonic and scramjet engines due to its superior thermal stability,high energy density,and ability to act as a coolant before combustion.However,it is known that...RP-3 is a kind of aviation kerosene commonly used in hypersonic and scramjet engines due to its superior thermal stability,high energy density,and ability to act as a coolant before combustion.However,it is known that coke can be generated during the cooling process as a carbonaceous deposition on metal walls and its effects on the cooling performance are still largely unknown.To explore the influence mechanism of porous coke on heat transfer characteristics of supercritical RP-3 in the regenerative cooling channel,a series of computational simulations were conducted via a three-dimensional CFD model considering solid wall,porous media and fluid simultaneously.The results show that the porous coke leads to the heat transfer deterioration,but when the coke layer thickness exceeds 1 mm,the weakening influence of coke on heat transfer becomes less important.The effect of porous coke on heat transfer under different inlet flow rates and wall heat fluxes was also analyzed and it was found that the heat exchange between channel wall and RP-3 is more detrimentally affected at large inlet mass flow rate.In a smooth channel,the heat transfer coefficient has a sudden rise along the flow direction,but the presence of porous coke mitigates the abrupt change.Furthermore,the variation of heat flux made a subtle difference in the effect of porous coke on the heat transfer of RP-3.展开更多
研究了超临界压力下碳氢燃料航空煤油RP-3在竖直细圆管内混合对流,分析了浮升力及热物性对碳氢燃料在垂直管中对流换热的影响。实验中控制热流密度从200～500 k W/m2变化,进口压力变化范围为3～5 MPa,进口雷诺数从5000～10500范围内变...研究了超临界压力下碳氢燃料航空煤油RP-3在竖直细圆管内混合对流,分析了浮升力及热物性对碳氢燃料在垂直管中对流换热的影响。实验中控制热流密度从200～500 k W/m2变化,进口压力变化范围为3～5 MPa,进口雷诺数从5000～10500范围内变化。研究表明：在向上流动情况中进口段存在较为明显的入口效应,换热出现恶化现象,而在向下流动中未出现;对于向上和向下流动,由于热物性的综合影响,换热系数沿流动方向增大;在较低进口雷诺数（Re=5 700）时,对于向下流动,随着浮升力影响的增大,浮升力改变了流体径向速度分布,出现了换热强化;在较高进口雷诺数（Re=10 500）时,浮升力对换热的影响依然显著;判别式Bo＊数小于5.6×10-7未能预测浮升力对碳氢燃料换热影响。展开更多
基金funded by Natural Science Foundation of Chongqing(No.CSTB2022NSCQ-MSX0416)Open Fund of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University)(No.PLN2020-8)+2 种基金Open Fund of Chongqing Key Laboratory of Fire and Explosion Safe(No.LQ21KFJJ02)Open Fund of State Key Laboratory of High Temperature Gas Dynamics(No.2021KF14)Sichuan Science and Technology Program(No.2022YFH0017)。
文摘RP-3 is a kind of aviation kerosene commonly used in hypersonic and scramjet engines due to its superior thermal stability,high energy density,and ability to act as a coolant before combustion.However,it is known that coke can be generated during the cooling process as a carbonaceous deposition on metal walls and its effects on the cooling performance are still largely unknown.To explore the influence mechanism of porous coke on heat transfer characteristics of supercritical RP-3 in the regenerative cooling channel,a series of computational simulations were conducted via a three-dimensional CFD model considering solid wall,porous media and fluid simultaneously.The results show that the porous coke leads to the heat transfer deterioration,but when the coke layer thickness exceeds 1 mm,the weakening influence of coke on heat transfer becomes less important.The effect of porous coke on heat transfer under different inlet flow rates and wall heat fluxes was also analyzed and it was found that the heat exchange between channel wall and RP-3 is more detrimentally affected at large inlet mass flow rate.In a smooth channel,the heat transfer coefficient has a sudden rise along the flow direction,but the presence of porous coke mitigates the abrupt change.Furthermore,the variation of heat flux made a subtle difference in the effect of porous coke on the heat transfer of RP-3.
