We modeled a conventional chiller shell & tube evaporator as a base case for designing a new, more efficient evaporator.
We modified the evaporator shell to best represent refrigerant liquid pool across the entire bottom. It is clear the gas/fluid takes the "path of least resistance"
Two-pass evaporator side view of water flow temperature with Delta-T 10f
We see greater heat transfer on the outside tubes of the bundle again suggesting "path of least resistance" reduces the energy transfer from the center tubes of the bundle
The Center 1/3 of the tubes show the majority of flow suggesting the outer 1/3's doing less energy transfer.
Our conclusion, there is room for improvement. Using data collected in this simulation we have designed an improved Evaporator. Anyone interested in this new design is welcome to contact us. NDA will be required.