Numerical study of the effect of rotating conical obstacle on heat transfer and fluid flow in a heat exchanger tube

In the present numerical study, the effect of conical obstacle on heat transfer and pressure drop in turbulent flow inside a tube is investigated. Although the effect of different stationary obstacles on heat transfer and pressure drop has been investigated so far, the use of the rotating obstacle is a new issue. Rotating obstacles create powerful rotating flow and increase flow turbulence and vortices through the effective displacement of the fluid particles affects the heat transfer rate. Therefore, the present research investigates the effect of cone obstacle rotation speeds of 25, 50, 75, 100 on the flow characteristics and thermal performance coefficients of the shell-and-tube heat exchanger in the Reynolds number range 4000 to 24000. The results show that for all Reynolds numbers in rotational speed 50 rpm, the heat transfer coefficient reaches its maximum value, and no significant change is observed, with increasing rotational speed. Heat transfer is about 2.2-2.9 times increased compared to smooth pipe and the thermal coefficient performance is in the range of 0.5-1.8. The maximum thermal performance coefficients, using rotating obstacle in comparison to the obstacle stationary one, is 120%.