Non-stationary convective heat transfer in an air synthetic impinging jet. Experiment and numerical simulation

Abstract

An unsteady local heat transfer in an air synthetic non-steady-state jet impingement onto a flat plate with a variation of the Reynolds number, nozzle-to-plate distance and pulses frequency is experimentally and numerically studied. Measurements of the averaged and pulsating heat transfer at the stagnation point are conducted using a heat flux sensor. The axisymmetric URANS method and the Reynolds stress model are used for numerical simulations. For local values of heat transfer, zones with the maximum instantaneous value of heat flux and heat transfer coefficient are identified. The heat transfer increases at relatively low nozzle-to-plate distances (H/d ≤ 4). The heat transfer decreases at high distance from the orifice and target surface. An increase in the Reynolds number causes reduction of heat transfer.

Current Review on Numerical Simulation of Synthetic Jet (SJ) Cooling

“…Lemanov et al, [48] has found that the stagnation Nu rises at short H/d. The intensity of heat transfer is found to diminish as the distance is increased farther and as Re rises.…”

“…In order to simulate the moving diaphragm of the jet as a moving wall boundary, user-defined function (UDF) has been used [29,40,45,52,55]. The governing equations of continuity, momentum and energy based on URANS (Unsteady Reynolds Averaged Navier-Stokes) has been mostly used [26,46,48,49,52,55].…”