Re: msg. 3rd FK equation for Joule heating (mems-talk digest,
Vol 1 #275 - 16 msgs)
Mariusz Zubert
2002-05-03
The heat balance can be described by the Fourier-Kirchoff equation
lambda*laplacian(T)+qv=rho*Cp*dT/dt (eq.1)
for the majority of homogeneous materials,
where:
lambda*laplacian(T) - describe heat flow by the particular material cell
qv - heat generation by the particular cell volume
rho*Cp*dT/dt - thermal inertia
The (eq.1) should be supplemented by the boundary and initial conditions.
The thermal dynamic properties is described by the specific heat Cp (more
precisely by the thermal diffusivity parameter a=lambda/(rho*Cp) and
boundary conditions).
The typical parameters:
Material lambda cp
rho - material density
Copper 389-356 [W/(mK)] 381-435[J/(kg
K)] 8900 [kg/m^3]
Air(20oC;0.1013MPa;dry) 2.59E-2 [W/(mK)] 1.005E3 [J/(kg K)] 1.205
[kg/m^3]
Best regards,
Mariusz Zubert