Heat transfer in turbulent separation region of pulsating flow behind a backward-facing step
I.A. Davletshin1,2, A.K. Aslaev1, N.I. Mikheev1, A.A. Paereliy1
1Institute of Power Engineering and Advanced Technologies RAS, Kazan, Russia
2Kazan National Research Technical University n.a. A.N. Tupolev, Kazan, Russia
Keywords: обратный уступ, отрыв потока, пульсации потока, число Струхаля, интенсификация теплоотдачи, backward-facing step, flow separation, flow pulsations, Strouhal number, heat transfer enhancement
Abstract
Heat transfer in a pulsating air flow was studied experimentally in the separation region behind a backward-facing step. The data on distributions of heat transfer coefficient have been obtained. At the distance of more than ten step heights away from the step edge, the heat transfer coefficient in pulsating flow deviated by no more than ±10 % from the steady flow values. Towards the step, heat transfer became more intensive relative to the steady regimes. Immediately beyond the separation edge, flow pulsations led to local twofold enhancement of heat transfer and even higher. In general, heat transfer augmentation in the separation region behind the step reached a maximum (70 %) at the Strouhal number Sh ~ 1.
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