超低负荷下炉膛管内汽水换热性能仿真研究
Simulation Study on Steam Water Heat Transfer Performance in Furnace Tubes under Ultra-Low Load

为了揭示超低负荷下炉膛管内汽水换热性能，本文以光滑管内超临界水换热特性为研究对象，采用SST k-ω模型描述湍流流动，对不同工况下超临界水流动换热规律进行了仿真研究。结果表明，在超临界水大比热区内，由于超临界水定压比热容大幅增加，且导热率小幅上升，超临界水本身的温度变化变得缓慢，导致换热系数增大；但当流体温度超过拟临界温度并逐渐远离，流体的定压比热容和导热率等物性参数会开始大幅降低，传热性能开始减弱，换热系数降低。
In order to reveal the heat transfer performance of steam water in furnace tubes under ultra-low load, this paper takes the heat transfer characteristics of supercritical water in smooth tubes as the research object, uses the SST k-ω model to describe turbulent flow, and simulates the heat transfer law of supercritical water flow under different operating conditions. The results show that in the high specific heat region of supercritical water, due to the significant increase in the specific heat capacity at constant pressure and the slight increase in thermal conductivity, the temperature change of supercritical water itself becomes slower, resulting in an increase in heat transfer coefficient; but when the fluid temperature exceeds the quasi-critical temperature and gradually moves away, the physical properties such as the constant pressure specific heat capacity and thermal conductivity of the fluid will begin to decrease significantly, the heat transfer performance will begin to weaken, and the heat transfer coefficient will decrease.