EXPERIMENTAL INVESTIGATION OF HEAT TRANSFER WITH A TRANSVERSELY PULSATING JET ON A FLAT PLATE

In this study, the effect of a transversely pulsating jet on heat transfer over a flat plate is investigated experimentally. The experimental study consists of a heater and a pulsating jet. The heater is made of a copper plate, has a constant heat flux, and is located in a wind tunnel. The pulsating jet is injected into the stream at the plate entrance. The pulsating jet is created using an oscillating movement of a piston-cylinder mechanism, and the secondary mass flux is supplied using a high-pressure blower. In the study, the Reynolds number in the main stream, the pulsating jet frequency and amplitude are changed, while the geometry and the other parameters remain constant for all cases. Furthermore, the effect of these parameters on heat transfer is analyzed. The experiments are performed for four different amplitudes and six different frequencies at four different blowing ratios. To explain the heat transfer mechanism, flow visualization is performed using the smoke wire method, and instantaneous flow images are obtained. It is observed that, the surface cooling performance increases with the increase of both the pulsating frequency and amplitude at high blowing ratios. The calculated experimental results are given as a function of dimensionless parameters.