超临界压力下水在方形环腔内垂直上升的传热特性

在西安交通大学超临界传热试验台上研究了超临界压力下水在方形环腔中垂直上升的传热特性.试验压力23～25 MPa;质量流速500～1 200kg/(m~2·s);热流密度200～800 kW/m~2;工质进口温度300～400℃.试验结果表明:带绕丝固定的方形环腔结构在高质量流速低热负荷的情况下,在拟临界区域传热会得到强化,而在低质量流速高热负荷的情况下,会发生传热恶化现象;较低的超临界压力下会有更加突出的传热强化表现,但是传热恶化会提前发生,并且更加剧烈,因此较高的超临界压力意味着安全性更高.

Upward Heat Transfer Characteristics of Supercritical Pressure Water in Square Annular Channel

Heat transfer in square annular upward flow channel was studied on the supercritical water heat transfer facility at Xi'an Jiaotong University. Experimental pressure is range of 23～25 Mpa, mass velocities of 500～1200kg/(m~2·s),heat fluxes of 200～800kW/m~2,and bulk inlet temperatures of 300～400℃.Experiment results showed that at high mass velocity and relatively low heat flux, the heat transfer in square annular geometry with helical wire-wrapped spacer would be enhanced, whereas at low mass velocity and relatively high mass flux, the heat transfer deterioration would occur. Comparison of experiment data showed that at lower supercritical pressure, heat transfer was enhanced more impressively but the deterioration was more likely to occur while relatively higher supercritical pressure means better security.