|Speciale, 3. modul, 2011, id:274|
|Findes på RUb:||Ja|
This thesis examines advantages and disadvantages by using a cylindrical or planar geometry when measureing specific heat in the frequency domaine. By using transfer matrices the heat diffussion equation is solved for the heat diffusion from a infinite long cylinder, a infinite plane and a sphere, and the thermal impedance is found. Different limits and boundary conditions are examined. For small frequencies it is seen, that the thermal impedance for the infinite plane diverges faster than for the infinite cylinder. Furthermore for the infinite cylinder it is seen, that at low frequencies the specific heat and the thermal conductivity is decouple making it possible to measure the thermal conductivity. This is not possible for the infinite plane, where only the thermal effusivity can be measured. That being said, the infinite plane enables an isolation of the thermal effusivity, while for the infinite cylinder the specific heat has to be extracted from modified Bessel function by for example numerical fit.