Address the issue with the current 3stream solver being able to only handle the intermediate fluid being the hot one.

[lcarasik]

This is an issue with Sekilc formulation not working well for non-intermediate fluids being the hottest one.

I want to look at the Ural method to see if it works better and it seems like a generalized version of the Selick formulation in terms of boundary conditions.

[lcarasik]

The Sekilc formuation found in https://drive.google.com/file/d/1M5TLWYmmC4C8HNz1UVlSQTe0nsB5AIXS/view?usp=sharing

The Ural method can be found here: https://www.sciencedirect.com/science/article/pii/S0735193398000864 - Formulation
The Ural method can be found here: https://www.sciencedirect.com/science/article/pii/S0735193301002317 - Case Studies

[lcarasik]

Here is a publication that leads us to that: https://www.sciencedirect.com/science/article/pii/S1290072904000511