当液体流经加热管时，在大部分液体达到饱和温度之前，可能会发生过冷的核沸腾和/或膜沸腾。在这种蒸发器管的过冷沸腾区域，热力学流动质量（蒸汽质量分数）为零，但根据流体性质、过冷度和传热速率，空隙率可能很大。再往下游，大部分流体达到与局部压力水平对应的饱和温度，并开始产生净蒸汽。在流动的后一部分，蒸汽的生成可以通过额外的核沸腾和/或通过现有液-汽界面处的蒸发进行。因此，我们决定建立一个实验设施，允许使用不同的流体、不同的直径和不同的方向进行测试。 由于迄今为止的大多数实验都处于较低的质量通量和热通量下，远远低于临界热通量，因此设计的测试回路的最大质量通量为6600 kg/sq mps，热通量高达12 x 104W/sq m，以覆盖调查较少的区域。因此，我们的实验集中在质量较低的区域，即核沸腾的区域。被认为是占主导地位的。引文:伊利诺伊州芝加哥ASHRAE Transactions第79卷第1部分

When a liquid flows through a heated tube, subcooled nucleate and/or film boiling can take place before the bulk of the fluid reaches its saturation temperature. The thermodynamic flowing mass quality (vapor mass fraction) would be zero in the subcooled boiling region of such an evaporator tube, but depending on the fluid properties, degree of subcooIing, and heat transfer rate, the void fraction could be substantial. Further downstream, the bulk of the fluid reaches the saturation temp corresponding to the local pressure level and net vapor generation commences. In this latter portion of the flow, the vapor generation can take place by additional nucleate boiling and/or by evaporation at existing liquid-vapor interfaces.We decided therefore to build an experimental facility which permitted testing with different fluids, different diameters and different orientations. Since the majority of the experiments to date are at rather low mass fluxes and heat fluxes, far below critical heat flux, the test loop was designed for maximum mass flux of 6600 kg/sq mps and a heat flux up to 12 x 104W/sq m in order to cover less investigated territory. Hence our experiments concentrated on the lower quality region, where nucleate boiling is. aSsumed to be dominant.