多孔表面管内高沸点工质的强化流动沸腾换热与阻力特性

ENHANCED FLOW BOILING HEAT TRANSFER OF HIGH SATURATION TEMPERATURE ORGANIC FLUID IN VERTICAL POROUS TUBE

建立了带有气液分离器的高沸点有机工质流动沸腾换热实验台 ,对垂直上升多孔表面管内高沸点有机工质异丙苯的强化流动沸腾换热与阻力特性进行了实验研究 ,获得了传热系数与压降随干度的变化情况 ,并与光管内的实验结果进行了比较 .另外 ,还通过实验得到了三个质量流速下的流动沸腾曲线 .实验过程中质量流速范围为 391～ 790 kg·m-2 ·s-1,实验工况干度范围为 0 0 9～ 0 5 8,压力范围为 0 16～ 0 31 MPa .通过对实验数据的回归分析 ,获得了传热系数与摩擦压降的计算关联式 .实验结果表明 ,多孔表面管在强化换热的同时 ,并没有使阻力增加很多 ,具有良好的应用前景 .

The experiments on enhanced flow boiling heat transfer in a vertical tube with porous coated surface were carried out with high saturation temperature organic fluid (cumene). Heat transfer coefficients and pressure drops vs. vapor quality were measured and compared to the experimental results of a smooth tube. Boiling curves at three different mass fluxes were also obtained. The range of test parameters in the test included the fluid mass flux of 391-790 kg &middot m-2 &middot s-1, the vapor quality of 0.09-0.58 and evaporating pressure of 0.16-0.31 MPa. The correlations for heat transfer coefficients and frictional pressure drops are derived, in which the effect of fluid molecular mass was introduced. The experimental results indicate that the heat transfer coefficients of the porous tube are 1.8-3.5 times those of smooth tube and the frictional pressure drops of the porous tube are 1.1-2.9 times those of smooth tube.