中文摘要：

基于一维两相四方程漂移流模型，采用数值模拟的方法对5MW低温核供热堆热工水力模拟回路（HRTL-5）的自然循环稳态特性进行模拟，分析了HRTL-5自然循环流量特性及其参数效应。结果表明：1）漂移流模型比均相流模型更适用于HRTL-5；2）当系统压力为1．5MPa时，系统自然循环流量随加热热流密度的升高而增加；3）当系统压力为0．5MPa时，系统自然循环流量随加热热流密度的升高先增加后减小；4）自然循环流量随加热段入口欠热度的升高而减小；5）当加热热流密度较低时，系统自然循环流量随压力的升高而减小，当加热热流密度较高时，系统自然循环流量随压力的变化呈现复杂状况。

英文摘要：

Based on the one-dimension two-phase drift flow model, the simulation of steady-state behaviors of natural circulation in HRTL-5 was performed. The natural circulation characteristic of HRTL-5 and its parameter effects were analyzed. The results show that the drift flow model is more suitable for describing the behaviors of HRTL-5 than homogeneous model. When the system pressure is 1.5 MPa, the natural circulation flow rate （NCFR） of the system increases with the increase of the heat flux. Moreover, when the system pressure is 0.5 MPa, the NCFR of the system increases first and then decreases with the increase of the heat flux. With the subcooling of the entrance fluid at heated section increases, the NCFR of the system decreases. Finally, with the increasing of system pressure, the NCFR of the system decreases at lower heat flux and exhibits complex features at higher heat flux.