ABSTRAKT

A detailed review of the archival literature on fluid dynamics, heat transfer, and shape optimization reveals that the optimal shape of natural convective cavities has not been investigated so far, and of course its physical features are not understood. A prominent application of cavities cooled by natural convection arises in the miniaturization of electronic packaging where some type of temperature constraint must be applied at the directly heated wall. Making a better design has always been the goal in engineering, this contemporary issue has been addressed in the present work in an elegant manner by linking a code on computational fluid dynamics with a shape optimization code. The case under study involves right-angled triangular cavities (dihedral cavities) with hot vertical walls, cold inclined walls connected from above by horizontal insulated walls. The optimization problem replaced the flat top wall of given length L into a semi-circular top wall of the same length L so that the apex angle for the latter is lowered. The finite volume method under the platform of the FLUENT code is used to perform the computational analysis. Once the velocity and temperature fields were accurately computed for a standard dihedral cavity with a certain apex angle and a specified heat load, an optimization procedure was implemented in a methodical fashion. A bird's eye inspection of the numerical results revealed that the optimized dihedral cavity is capable of transfering more heat. The present study was motivated by the need for miniaturization of cooling systems that use natural convection cavities for the removal of heat. An important issue of changing the fluid medium from air to a gas of equal or less weight, but superior thermal buoyant features is also addressed.