July 31, 2020 at 2:17 pmKeyur KanadeAnsys EmployeeHello, how do I know if I can use the 'lumped-capacitance' model of transient heat transfer for a particular problem?
July 31, 2020 at 2:17 pmKarthik RAdministrator
Hello @kkanade , you can use Biot number to quickly check if the lumped-capacitance assumption is valid or not for a particular problem. Biot Number is the ratio of conduction resistance to convective resistance. It is mathematically defined as:
Bi = h*L / k
h = heat transfer coefficient [W/(m^2-K)]
L = conduction length scale [m],
k = thermal conductivity [W/(m-K)]
For Smaller values of Biot number the heat conduction inside the body is faster than the heat convection at its outer surfaces, and therefore the temperature gradients inside the body can be neglected. Bi in the range of <0.1 typically leads to an error of <5% if lumped-capacitance model is used.
July 31, 2020 at 2:18 pmKeyur KanadeAnsys EmployeeHi @Kremella
thank you for the response. I really appreciate it.
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