Natural convective heat transfer in the air-filled interstice between inclined concentric hemispheres Application to thermoregulation in electronics

Purpose - The main purpose of this work is to quantify the convective heat transfer occurring between two inclined and concentric hemispheres. Design/methodology/approach - The inner one is an electronic assembly generating a constant heat flux during operation. The outer hemisphere is maintained isothermal at cold temperature. The interstitial space is air-filled. The base of the equipment can be inclined with respect to the horizontal plane by an angle ranging from 0 degrees (horizontal position with dome faced upwards) to 180 degrees (horizontal position with dome faced downwards). Findings - Nusselt-Rayleigh correlations are proposed for several configurations obtained by varying the generated power and the base inclination. The large resulting Rayleigh number ranging between 2.4 x 10(5) and 1.7 x 10(7) allows using these new and original correlations in various engineering fields, such as electronics in the present work. The calculations are realized by means of a 3D numerical approach based on the finite volume method. Originality/value - The geometry and the thermal boundary conditions considered in the present survey are suitable for applications inmany engineering areas.