Parametric thermal modeling of heat transfer in handheld electronic devices

The dimensions and power dissipation information of various commercial handheld electronics were collected to find benchmarking size and power ranges. The relationship between device size parameter, defined as total volume divided by external surface area, and the power dissipation was determined. Three dimensional finite element models were used to model the conduction, natural convection, and surface-to-surface radiation phenomena inside of the devices. Simulations were performed of four designs of handheld mockups with three boundary conditions on the enclosure modeling the device operating in free air, handheld, and in a clothing pocket. Various combinations of external case and circuit board conductivity were modeled. The ratio between the thermal resistance internal to the device and the resistance from the case surface to the ambient were also determined.