Numerical simulation of boundary conditions and the onset of instability in natural convection due to protruding thermal sources in an open rectangular channel

Two-dimensional natural-convection heat transfer to air from multiple identical protruding heat sources, which simulate electronic components, located in a horizontal channel which is open on both sides, has been studied numerically. Of particular interest is the accurate simulation of realistic boundary conditions in such a channel. The effects of source temperatures, channel dimensions, openings, boundary conditions, and source locations on the heat transfer from and flow above the protruding sources are investigated, and the onset of instability is studied. The results indicate that the channel dimensions and the presence of openings have significant effects on the fluid flow. However, their effects on heat transfer are found to be relatively small. The increase in channel height is seen to lead to a less stable flow and, consequently, a decrease in the critical Grashof number. Numerical simulation of the flow at the openings is investigated and found to be crucial to an accurate modeling of the transport.