Abstract:

In order to investigate the effects of turbulators on the heat transfer in ribbed channels,the heat transfer and flow characteristics of elliptical ribbed channels with and without deflector are numerically simulated by using a realizable k-ε turbulence model,and the results are compared with those of the traditional grooved channel. The results show that the heat transfer coefficient of elliptical ribbed channel is about 3 －4 times that of the traditional
grooved channel,that the heat transfer coefficient and the pressure drop both increase with the rib height,that the adoption of deflector remarkably raises the heat transfer coefficient,that the heat transfer coefficient of the ribbed channel with deflector mounted at the top of rib downstream is 33% higher than that of the channel without curved vanes,and that,with the movement of the deflector along the arc length of ribs,the heat transfer coefficient first increases and then decreases,while the pressure drop continuously decreases. Moreover,it is found from comprehensive comparison that the ribbed channel is of the highest comprehensive performance when the deflector are mounted at the location of 0.9 time arc length of the rib downstream,that the heat transfer coefficient reaches the maximum when the vanes are mounted at the location of 0.7 time arc length of the rib downstream,and that the nearness of the deflector for the flow separation point is favorable for the heat transfer enhancement.

Key words: heat transfer enhancement, elliptical rib, grooved channel, deflector, numerical simulation