b／a＝0．5的椭圆形通道内非牛顿流体的强化传热

对非牛顿流体在小尺寸椭圆形通道内的层流受迫对流传热进行了实验研究。实验介质为１５００Ｗｐｐｍ的Ｃａｒｂｏｐｏｌ－９３４中性水溶液。采用直接通电的方法对管壁四周等热流加热。结果表明，椭圆通道内，非牛顿流体Ｃａｒｂｏｐｏｌ水溶液的换热强于牛顿流体水，约高出水５０％左右，说明粘弹性流体在椭圆形通道内也产生二次流并能强化换热；与同种浓度的Ｃａｒｂｏｐｏｌ水溶液在方形通道内的换热结果相比，椭圆通道内的换热高于方形通道。流体的压力降则不受粘弹性的影响，仍符合幂律流体的阻力系数关系式（ｆ＝１６／Ｒｅ＊）。

HEAT TRANSFER ENHANCEMENT OF NON-NEWTONIAN FLUID IN THE ELLIPTICAL DUCT OF b/a=0.5

An experimental study has carried out for laminar forced convection heat transfer of non-Newtonian fluid in a small scale elliptical duct. The fluid mediun used in the experiment was the neutralized aqueous 1500 Wppm Carbopol-934 solution. All the wall of the elliptical duct were heated with constant heat flux by direct electrifying. Results show that the heat transfer of non-Newtonian Carbopol solution is greater about 50 percent than that of Newtonian water. It is illustrate that the secondary flow is produced and the heat transfer can be enhanced for the viscoelasticity fluid in the elliptical duct.The heat transfer in the elliptical duct is higher than that of the square duct in the same concentration of Carbopol solution. And the fluid friction factors are almost unaffected by the viscoelasticity, it is in excellent agreement with the power-law priction of Kozicki(f=16/Re*).