Abstract
This paper presents an experimental study of natural convective air cooling of a printed-circuit-boards (PCBs) array in a closed casing with inclination. The results reveal that in both cases (without and with inclination) an unstable thermal boundary layer exists on the top wall of the casing. This unstable boundary layer, which interacts with the air flow rising up from the channels between the PCBs, produces vortex flow and temperature oscillation. In the inclined casing warm air gathers together in the upper corner of the casing and cold air falls down to the bottom corner. Therefore, the cooling effect on the PCBs in the region near the bottom corner of the casing increases and that in the region near the upper corner decreases. It should be noted that the temperature of the PCBs located near the upper corner can exceed the allowed maximum working temperature designed for levelly adjusted casing and cause an overheating of electronic elements. An empirical correlation deduced from the experimental results is presented in the form of Nu = f(Ra, α) with the modified channel Rayleigh number ranging from 102 to 105 and with an angle of inclination from 0° to 30°.
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© 1994 Springer Science+Business Media Dordrecht
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Mayinger, F., Wang, Z.G. (1994). Experiments on Natural Convective Air Cooling of a PCBs Array in a Closed Casing with Inclination. In: Kakaç, S., Yüncü, H., Hijikata, K. (eds) Cooling of Electronic Systems. NATO ASI Series, vol 258. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-1090-7_8
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DOI: https://doi.org/10.1007/978-94-011-1090-7_8
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