Learning Forum

[Raul Jr. Regis]

I am simulating a cold storage room with an initial temperature of -17C. The objects inside the room are initially -5C using patch. There is also an inlet air of -24C and runs for 20 minutes. my problem is the temperature of the objects stay at -5C even after 20 min. I am still learning the basics but this is the project and problem I have encountered for now. Thank you so much for any help.

[Raul Jr. Regis]

Here is the drive link containing the archive of my project

https://drive.google.com/file/d/1t0pGoAXarXN-RvPstj3PTUcYwIDExlUg/view?usp=sharing

[Rob]

Staff aren't permitted to download or open any files - it's a requirement from legal to allow us to answer questions. 

Can you show the cell zone condition of the cold zone? If you check fluxes do you see any heat transfer between zones? 

[Raul Jr. Regis]

 

Here is the cell zone condition of the cold zone (air domain)

Checking the wall heat flux from the pallets (hot zone) are negative. Does this mean heat is going out? So i checked the material properties if it might help. I changed the aluminium properties similar to poultry.

 

[Rob]

That's the air cell zone condition. What's the solid set as? 

[Raul Jr. Regis]

Here is the solid cell zone condition. Thank you

[Rob]

That's correct. 

Can you plot temperature and velocity as per the first image in the thread in Fluent, but plot with node values off. You settings look OK from what you've shown me, so we need to focus on what's going on in the domain. 

[Raul Jr. Regis]

I am not sure what you mean by node values off but I will just figure it out later. I used point location in post processing and placed it inside the heat source (pallet). It seems to decrease very little so the problem may have been due to the parameters?

[Rob]

Hard to tell without reviewing the whole model, and I can't do that due to the contraints we work to on here. Node values are easier to find in the Fluent post processing. 

[Raul Jr. Regis]

May I know what settings for the plot I should select here. Thank you

[Rob]

Contour

[Raul Jr. Regis]

Thanks, here are the temperature and velocity contour of the domains.

[Rob]

Displaying on the interior domains isn't recommended as it's the default label for all cell facets so can cause the computer to crash as the graphics load becomes rather high. In this case it looks to show the blocks are cooling, albeit slowly. Look under the "New Surface" option to create iso-surfaces (of mesh) or planes to replicate the CFD Post image.

I'd only use Total Temperature for compressible systems, Static is usually sufficient. 

[Raul Jr. Regis]

Thanks for the explanation. I was able to create two planes and plotted with node values off.

[Rob]

 

OK, so looking at that you’ve got virtually no flow around the hot part, and all of the flow goes “over” the section that needs cooling. So, what is between the air flow and warm blocks? It also looks like the inlet condition is adjacent to a wall? That’s not a good idea, unless that’s how the system was designed? 

To add, you really want to be getting IT to install 2023R2: R19.2 is about 5 years old now.