How to find biot-number?

Question

I have an assignment where i need to find the biot-number to see if the lumped-element model can be used for predicting the cooking time of a liver pate.
I have 1 kg of liver pate in an oven at 220 degrees celcius. i need to bring it up from 20 degrees to 75 degrees core temperature. i know the density, specific heat capacity and the thermal conductivity. I just cant find "h" the heat transfer coefficient.

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Answer 1 · 2018-07-04T13:34:28

The Biot-number #B_i# for a lumped heat analysis is given as

#B_i=\frac{hL}{k_s}#

Where, #h# is convective heat transfer coefficient of ambient fluid

#L# is the characteristic length of the system/solid body exchanging heat with the ambient through convection

#k_s# is the thermal conductivity of the system/solid body

For lumped heat system to be applicable

#B_i<0.1#