Numerical simulations of flow and heat transfer to supercritical RP-3 through the inclined tubes have been performed using LS k–e model embedded in Fluent. The physical properties of RP-3 were obtained using the gene...Numerical simulations of flow and heat transfer to supercritical RP-3 through the inclined tubes have been performed using LS k–e model embedded in Fluent. The physical properties of RP-3 were obtained using the generalized corresponding state laws based on the fourcomponent surrogate model. Mass flow rate is 0.3 g/s, system pressure is 3 MPa, inlet temperature is 373 K. Inclination of the inclined pipe varied from -90° to 90°, with heat flux varied from 300 k W/m^2 to 400 kW/m^2. Comparison between the calculated result and the experimental data indicates the range of error reasonable. The results of ±45° show that temperature inhomogeneity in inclined pipe produce the secondary flow in its cross section due to the buoyancy force. Depending on the strength of the temperature inhomogeneity, there will be two different forms of secondary flow and both contribute to the convective heat transfer in the pipe. The secondary flow intensity decreases when the inhomogeneity alleviates and thermal acceleration will play a leading role. It will have a greater impact on the turbulent flow to affect the convective heat transfer in the pipe. When changing the inclination, it affects the magnitude of the buoyant component in flow direction. The angle increases, the buoyancy component decreases. And the peak temperature of wall dominated by the secondary flow will move forward and increase in height.展开更多
空间熔盐堆运行过程中,反应性控制起到十分重要的作用,目前陆地上常采用的主动反应性控制方式存在出现故障的概率等问题。空间熔盐堆需要一种非能动反应性控制方式,在无需外源及人为操控情况下,对反应性实施自动控制,降低事故发生风险...空间熔盐堆运行过程中,反应性控制起到十分重要的作用,目前陆地上常采用的主动反应性控制方式存在出现故障的概率等问题。空间熔盐堆需要一种非能动反应性控制方式,在无需外源及人为操控情况下,对反应性实施自动控制,降低事故发生风险。本文针对热管式液态燃料空间熔盐堆,利用液态燃料的热胀冷缩机制,当堆芯处在正常运行工况下温度发生变化时,提出并设计一种液态燃料移出移入非能动反应性控制系统(Liquid Fuel in/out Transfer in a Passive Reactivity Control System,LFT-PRCS),并对含有该系统的堆芯进行在正常运行工况下物理特性分析,以及该系统结构参数与反应性补偿能力分析。结果表明:正常运行工况下,含有LFT-PRCS的堆芯具有更负的反应性,且堆芯物理特性未发生明显变化;LFT-PRCS中毛细管道较佳结构参数为:高度为10 cm、内层半径为0.2 cm、外层半径为0.4 cm;LFT-PRCS在寿期初、寿期末温度发生2 K波动时,可向堆芯引入约20 pcm的反应性。上述结果表明,LFT-PRCS可提高堆芯固有安全性,一定程度上补偿燃耗造成的反应性损失。展开更多
基金funding support from National Natural Science Foundation of China (No. 51876005)
文摘Numerical simulations of flow and heat transfer to supercritical RP-3 through the inclined tubes have been performed using LS k–e model embedded in Fluent. The physical properties of RP-3 were obtained using the generalized corresponding state laws based on the fourcomponent surrogate model. Mass flow rate is 0.3 g/s, system pressure is 3 MPa, inlet temperature is 373 K. Inclination of the inclined pipe varied from -90° to 90°, with heat flux varied from 300 k W/m^2 to 400 kW/m^2. Comparison between the calculated result and the experimental data indicates the range of error reasonable. The results of ±45° show that temperature inhomogeneity in inclined pipe produce the secondary flow in its cross section due to the buoyancy force. Depending on the strength of the temperature inhomogeneity, there will be two different forms of secondary flow and both contribute to the convective heat transfer in the pipe. The secondary flow intensity decreases when the inhomogeneity alleviates and thermal acceleration will play a leading role. It will have a greater impact on the turbulent flow to affect the convective heat transfer in the pipe. When changing the inclination, it affects the magnitude of the buoyant component in flow direction. The angle increases, the buoyancy component decreases. And the peak temperature of wall dominated by the secondary flow will move forward and increase in height.
文摘空间熔盐堆运行过程中,反应性控制起到十分重要的作用,目前陆地上常采用的主动反应性控制方式存在出现故障的概率等问题。空间熔盐堆需要一种非能动反应性控制方式,在无需外源及人为操控情况下,对反应性实施自动控制,降低事故发生风险。本文针对热管式液态燃料空间熔盐堆,利用液态燃料的热胀冷缩机制,当堆芯处在正常运行工况下温度发生变化时,提出并设计一种液态燃料移出移入非能动反应性控制系统(Liquid Fuel in/out Transfer in a Passive Reactivity Control System,LFT-PRCS),并对含有该系统的堆芯进行在正常运行工况下物理特性分析,以及该系统结构参数与反应性补偿能力分析。结果表明:正常运行工况下,含有LFT-PRCS的堆芯具有更负的反应性,且堆芯物理特性未发生明显变化;LFT-PRCS中毛细管道较佳结构参数为:高度为10 cm、内层半径为0.2 cm、外层半径为0.4 cm;LFT-PRCS在寿期初、寿期末温度发生2 K波动时,可向堆芯引入约20 pcm的反应性。上述结果表明,LFT-PRCS可提高堆芯固有安全性,一定程度上补偿燃耗造成的反应性损失。
