Heat Transfer - Chapter 5 - The Lumped Capacitance Approximation

In this video lecture on transient conduction, we introduce the lumped capacitance approximation. This is a method to assume that a solid's temperature is uniform with respect to space. This allows us to solve the problem when only considering the solid's change in temperature with respect to time. We also define the Biot number and discuss how it can be used to determine whether the lumped capacitance approximation is valid for a particular system.

[@soloplay1319]

hello, can I get access to the textbook that you are extracting these courses from please?

[@alicanak3886]

Air convection coefficient depends on film temperature, therefore h values can be different at both sides. We must check Biot number for both halves of the flat plate to be able to assume that it's a lumped capacitance.

[@yasamanjabbari6477]

What if a solid suddenly into contact with another solid in a different temperature and we want to use the lumped capacitance method? How do we write the energy balance?

[@dailybiblereading4937]

What if we don't neglect radiation in the first case, meaning convection + radiation? do we still use this method?

[@sainagupta6475]

is lumped capacitance approximation is valid if we don't ignore the radiation term ?

[@indianmanhere]

then it will also depend on x so it will not be valid.... it becomes too complex, and for this, we can use Heisler charts.
Reply after 7 months....none of any use 😅😂😂

[@indianmanhere]

we can check validation by using the Biot number which should be < 0.1

[@sainagupta6475]

@@indianmanhere no worry

[@indianmanhere]

@@sainagupta6475 Tomorrow is my midsem exam of this subject 🤕
In radiation it's get too complicated🥲