Natural convection in inclined hemispherical cavities with isothermal disk and dome faced downwards. Experimental and numerical study

The objective of this work is to propose correlations of Nusselt Rayleigh type for controlling the thermal state of electronic devices used in various engineering sectors such as thermoregulation of electronic devices, solar energy, aeronautics or safety and security. The assemblies are contained in hemispherical air-filled cavities whose disk is maintained isothermal and inclined at an angle varying between 90 degrees (vertical position) and 180 degrees (disk horizontal with isothermal dome oriented downwards). The numerical approach performed by means of the finite volume method for Rayleigh numbers varying between 10(4) and 5 x 10(8) is validated by measurements for various combinations of inclination angle and Rayleigh number. The results of this work show that the natural convective heat transfer are between 13% and 21% higher when the disk is maintained isothermal as compared to the case corresponding to imposed heat flux on the disk, for the same inclination angle and Rayleigh ranges. (C) 2014 Elsevier Ltd. All rights reserved.