Clemens J.M. Lasance Philips Research Laboratories Emeritus The last time the subject of my column was: ‘Most of us don’t live in wind tunnels, neither in the world of Nusselt.’ I promised more comments about the (mis)use of the heat transfer coefficient h in real-life applications where we are dealing with multiple sources, anisotropic PCBs and multilayers. In this column … [Read more...]
Using an Equivalent Heat Transfer Coefficient to Model Fins on a Fin
Many readers of ElectronicsCooling are probably familiar with the use of fin efficiency formulas to estimate the thermal resistance of the commonly used parallel plate fin heat sink. Given the heat transfer coefficient, h, acting on a fin and the dimensions of the fin, the thermal resistance of an individual fin is given by: where Af and η are the surface area and … [Read more...]
The Benefits Of Using Hadiabatic In Thinking About Electronics Cooling
The heat transfer coefficient is used to describe convective heat transfer between a solid and a fluid, as in Equation (1). The heat transfer coefficient is a defined parameter, not a physical property like thermal conductivity, and different definitions are used for different situations. The preferred definition for use in the electronics-cooling situation is … [Read more...]
Estimating Parallel Plate-Fin Heat Sink Thermal Resistance
As noted previously in this column, the trend of increasing electronic module power is making it more and more difficult to cool electronic packages with air. As a result there are an increasing number of applications that require the use of forced convection air-cooled heat sinks to control module temperature. An example of a widely used type of heat sink is the parallel plate … [Read more...]
Estimating Natural Convection Heat Transfer for Arrays of Vertical Parallel Flat Plates
A simple formula to estimate the natural convection heat transfer coefficient on a flat plate was presented in a preceding column [1]. If, instead of a single plate, we wish to consider a closely spaced array of vertically oriented parallel flat plates, a different formula is required. The geometry to be considered appears in Figure 1 and is typical of that for a vertically … [Read more...]
