In last issue's column, we discussed heat loss by convection and radiation from a printed circuit board in which heat spreads in a 2-D pattern. Here, we look at a slightly simpler situation, namely that of heat transfer by a fin into the ambient air. The situation is illustrated in Figure 1, where, for simplicity, the heat is shown flowing only out of the top surface of the … [Read more...]
Improving productivity in electronic packaging with flow network modeling (fnm)
As the complexity and power density of electronics systems increase, so too does the demand for tools to improve both product quality and designer productivity. This is especially true for thermal designers who use Computational Fluid Dynamics (CFD) tools for thermal designs. Several important factors are driving this trend: System complexity has increased to the point that … [Read more...]
The thermal conductivity of pure metals
As discussed previously in this section, the measurement of the thermal conductivity is notoriously difficult. The consequence is that, while the measurement accuracy by individual researchers is claimed to be of the order of 2%, laboratories participating in round-robin tests produce results differing from each other by 15% or more [1]. Even the measurement of pure metals is … [Read more...]
Convection and radiation heat loss from a printed circuit board
In last issue's column, a method for calculating the thermal conductivity of a printed circuit board (PCB) was described. Now, we look at a more complicated heat transfer process, namely the loss of heat from the surface of a PCB to the ambient air. This situation is more challenging to describe mathematically since it involves the simultaneous processes of heat spreading by … [Read more...]
Cooling Electronics at High Altitudes Made Easy
Introduction High altitude air cooling has always been somewhat of a mystery to the uninformed. The first reaction to the situation is that there is just not enough air at altitudes greater than six kilometers (20,000 ft). At times this may be true, but many things can be done to improve the cooling and obtain an acceptable design. The most important thing to remember when … [Read more...]
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