狭缝孔板表面换热性能的试验研究

EXPERIMENTAL RESEARCH ON HEAT TRANSFER FROM SLOT SLAT PLATE SURFACES

采用萘升华模拟试验方法测量了狭缝孔板表面的强迫对流换热性能。通过试验观察 ,在迭置的若干块孔板中 ,从第一块板开始 ,叉排时换热逐渐增强 ,顺排时逐渐减弱 ,第五块孔板上的换热已经稳定。叉排的换热总是比顺排好。顺排布置时选择厚隔板换热较好 ,叉排时薄隔板较好。顺排时孔板本身的厚度对换热几乎无影响。在经过试验的 2 6 <Re<5 40的范围内 ,顺排时的数据在双对数坐标上是一条直线 ,可以用 Nu=1.2 17Re0 .389Pr0 .36来拟合 ,而叉排的数据只在 Re<2 0 0时大致是一条直线 ,Re<2 0 0时上升加快 ,这是由于流速增大使扰动加剧 ,导致换热强化。

Experimental investigation on forced flow convective heat transfer characteristics of slot slat plates in a stack of alternately arranged slot plates and spacer plates was performed by employing naphthalene sublimation technique.In staggered arrangement,it was observed that heat transfer gradually increased from the first plate on and reached a stable value on the fifth plate.For in line arrangement,heat transfer decreased gradually but also reached a stable value on the fifth plate,and this stable value is lower for in line than for staggered arrangement.Better heat transfer results are obtained by using thicker spacer plate for in line arrangement,where as thinner spacer plate is preferred for staggered one.Thickness of slot plate has little influence on heat transfer for in line arrangement.Within the tested range of 26< Re <540,data from each group of geometrical parameter fell into a straight line on double logarithm chart,and data of some selected groups can be presented as Nu =1 217 Re 0 389 Pr 0 36 .For staggered arrangement, Nu increases faster at higher Re region due to higher flow turbulence and can not be treated as a straight line.