Thermal Characteristics of Horizontally Oriented Electronic Components in an Enclosed Environment

A closed-form expression is derived to correlate experimental data relating the thermal characteristics of electronic hardware in an enclosed system. Due to the geometric constraints sometimes imposed in small system architecture, the analysis concerns itself only with the effect of horizontal orientation. Variations in the enclosed volume create changes in the buoyancy-induced flows which affect the thermal characteristics of an adiabatic fiat plate. Data from the fiat plate study are correlated against additional data using a typical memory card populated with area-pin array modules. The results provide a technique to obtain the surface heat transfer coefficient and thus the natural convection component of the total heat load. Radiation losses, which play a major role in this type of system, are also discussed. A combination of these two components yield the maximum power dissipation allowable to maintain a specified electronic component temperature within an enclosed system with known bulk air temperature limits.