Experimental and Theoretical Studies on Air Exchange in Portable DevicesM. Olin , L. Laakso , J. Hannula , T. Galkin , K. Väkeväinen , and K. Hartikainen 
 University of Helsinki, Finland
 Nokia Corporation, Finland
 Ambertec Oy, Finland
In this paper, we perform a leakage analysis fitted to approximate analytical diffusion and air exchange models, by the helium injection method for one mobile phone type.
In order to extend the applicability of our models, we developed a more complicated numerical model for diffusion, thermal conduction and free convection inside the phone.