Heat Transfer from Pulsating Laminar Impingement Slot Jet on a Flat Surface with Inlet Velocity: Sinusoidal and Square Wave

ABSTRACT

Heat transfer from a pulsating laminar impingement slot jet on a flat surface was investigated numerically and experimentally. Inlet velocity was considered sinusoidal velocity and square wave velocity. Experimental studies were done only for the sinusoidal velocity state. An inverse heat conduction method, conjugated gradient method with adjoint equation, was used for the experimental estimation of the local heat transfer coefficient along the target surface. Effect of the square wave velocity of the laminar impingement slot jet was studied numerically. The results show pulsations in flow change flow patterns and the thermal boundary layer thickness because of the newly forming thermal boundary layer is extremely small each time the flow is resumed. Heat transfer rate in this state enhances due to pulsating inlet velocity in comparison with steady state. Heat transfer increases with increasing pulsation amplitude. Enhancement in mean heat transfer on the target plate for sinusoidal velocity is rather than square wave velocity.

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Notes on contributors

Somayeh Davoodbadi Farahani

Somayeh Davoodabadi Farahani received her PhD in Mechanical Engineering in 2015 from Tehran University, Tehran, Iran. Her research areas of interest include: experimental investigations in heat transfer, the use of numerical and analytical methods of solution of the heat transfer pro, direct simulation of thermal systems, solution of inverse heat transfer problems, and optimization of thermal systems.

Farshad Kowsary

Farshad Kowsary is a professor in the field of heat transfer at the University of Tehran, Iran. His research interests are in the area of inverse heat transfer with a focus on inverse radiation and conduction. He has a sizable number of papers in the above subjects in reputable heat transfer journals. He is a major reviewer for the Journal of Quantitative Spectroscopy and Radiative Transfer as well as Heat and Mass Transfer.