Heat and Mass Transfer: Nodal Networks

[jdawg]

Homework Statement

So this is more of a really vague conceptual question, I'm sorry if it doesn't really make sense. I'm in the stage of learning this where I don't quite understand things well enough to form a proper question.

I'm a little bit confused about nodal networks in heat and mass transfer. At the beginning of the semester when we did resistive networks, we used temperatures at the nodes of the network. Then we studied exclusively radiation, and black body emissive power and sometimes radiosity were used at the nodes of the network. Finally we studied multi-mode heat transfer, and some nodes in the network were temperature and some were emissive power or radiosity.

I guess I'm confused about when to use which? I'm pretty good at guessing at what to use at the nodes just from looking at which chapter the problem falls in, but I want to understand what I'm doing. I appreciate any help!

 

[donpacino]

Homework Statement

So this is more of a really vague conceptual question, I'm sorry if it doesn't really make sense. I'm in the stage of learning this where I don't quite understand things well enough to form a proper question.

I'm a little bit confused about nodal networks in heat and mass transfer. At the beginning of the semester when we did resistive networks, we used temperatures at the nodes of the network. Then we studied exclusively radiation, and black body emissive power and sometimes radiosity were used at the nodes of the network. Finally we studied multi-mode heat transfer, and some nodes in the network were temperature and some were emissive power or radiosity.

I guess I'm confused about when to use which? I'm pretty good at guessing at what to use at the nodes just from looking at which chapter the problem falls in, but I want to understand what I'm doing. I appreciate any help!

To give perspective I am an electrical engineer, but I have used nodal networks to analyze some heat problems as well. I will take a shot at answering this question.

A nodal network is simply a mathematical/graphical tool to represent and derive values. see the following link for reference: https://drive.uqu.edu.sa/_/kmguedri/files/A-HT-1-Chap5.pdf

My question for you, if both temperature and emissive power are represented, what is the relationship between them?
In general for a problem you have known inputs and required outputs. You use known vlaues about your model, along with known inputs to work your way to the required outputs. If known inputs are both emisive power and temperature, then you'll need to work your model to include both of them, which will require a known relationship between them.