More Lumped Capacitance

Last post we looked at another extension of lumped capacitance beyond our original exploration here and here.  In the last post, we looked at a case where the heat transfer coefficient increased linearly with time, which might be a good approximation for the initial moments of the heat transfer for an object in a duct with the fan just starting up.  Today we’ll look at a case where the heat transfer coefficient is decreasing.

Lumped Capacitance Revisited

Lumped capacitance is a very useful heat transfer approximation that we mentioned originally here,  and explored in more depth with extensions here and here.  Today, we’ll look at another extension of the basic lumped capacitance approach.

Finite Quench Revisited

We looked earlier at the solution for quenching an object in a finite bath—that is, where the bath is small enough (relative to the object being quenched) that the bath temperature rises while the object’s temperature goes down.  As you’d expect, eventually the object and the bath arrive at the same equilibrium temperature.  Today, we’ll look at getting the quenched object to two specific temperatures at two different times.

More Useful Lumps (Part 2)

In our last post, we examined the case of lumped capacitance where the free-stream temperature was a function of time and presented the equation governing that situation. This time, we’ll look at some specific examples.

More Useful Lumps

All beginning heat transfer classes cover the topic of lumped capacitance calculations: the case where heat conduction within a body is fast enough that the entire body can be considered to be at a single temperature. 

This is a very useful tool for estimating heat transfer in some situations.   However, with just a little work, we can extend the tool to a broader application.