Computational and Experimental Study of Heat Transfer on the heat sink with an impinging synthetic jet under Various Excitation Wave

Abstract

This work presents an investigation of an impinging synthetic jet produced by a continuous movement of an oscillating piezoelectric membrane in a synthetic jet actuator (SJA). The jet stream blows from the top of the heat sink attached to an electrically heated mat, and is used to enhance heat transfer to simulate a microelectronic component cooling system. Experimental measurements and numerical simulation were conducted to elucidate the distribution of forced convective heat transfer. The membrane's movement was set to produce a synthetic jet for a complete cycle to investigate flow dynamics in suction and blowing streams. The purpose of this research is to characterize synthetic jet membrane vibrations using sinusoidal, square, and triangular wave excitation modes to find which mode is best for vibrating the synthetic jet membrane. The membrane was excited with various functions, including sinusoidal, triangular, and square waveforms with frequency of 80 Hz, 120 Hz, and 160 Hz. The synthetic jet flow simulation utilized a commercial CFD software, FLUENT and DesignModeler to generate an element meshing with total mesh volume of 537.422. The amplitude for all membrane waves is assumed to be 2 mm/s. A k-ω Shear Stress Transport turbulence model was used to complete the simulation. A user-defined function model was developed to drive the piezoelectric membrane using various sinusoidal and non-sinusoidal excitation waves. Measurements were conducted using thermocouples with an automated data acquisition system to obtain temperature data and derive heat transfer coefficients.The conclusion from this research is that the 120 Hz square wave excitation mode produces the best heat transfer value. This research can contribute to the development of synthetic jet models for the microelectronic component cooling system industry.