The performance of active cooling in a mobile phone

Power dissipation levels in mobile electronics devices are heading towards five watts and above. With this power dissipation level, products such as mobile phones will require active cooling to ensure that the devices operate within an acceptable temperature envelop from both user comfort and reliability perspectives. To the authors knowledge no studies to date have been carried out to determine the potential performance of fans within mobile phone architectures. In this paper a centrifugal fan is implemented into a Nokia mobile phone. Its performance is compared in terms of aerodynamic characteristics, maximum phone surface temperature, and allowable phone heat dissipation, for various levels of blockage in the phone, which are simulated using perforated plates with varying porosity. The results show that for the best case scenario, with minimal blockage increased power dissipation levels of order 75% can be achieved but with realistic blockages this value is more likely to be in the region of 50%.