Numerical and experimental study of the effect of inclination on the thermal behaviour of natural convection inside a thin electronic equipment casing

Abstract

With rapid increase in the power dissipation density in modern electronic equipment, the cooling design of electronic equipment becomes increasingly important. For widely used forced-convection air-cooled systems, the reliability and acoustic noise of the fan present serious concerns as the air velocity is increased to enhance the cooling capacity. Thus, the interest in natural-convection air cooling is growing to take advantages of the low noise and energy saving inherent in that cooling mode. One method of promoting the capacity of natural air cooling is to incline the electronics casing and thereby induce draft air by what is called the chimney effect. However, the effect of inclination on the thermal behaviour and the cooling capacity has not yet been fully understood owing to the involvement of many parameters in driving the draft air. This paper presents the results of experimental and numerical studies on the effect of casing inclination on the temperature rise across the casing. Numerical simulation was carried out to find the thermal behaviour inside a thin electronic equipment casing. The simulation results are in good agreement with experimental data. A thermal design guide is obtained regarding how the cooling effect is improved by increasing the inclination angle.