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Point Parameters - Heat Flux vs Surface Heat Flux

Question asked by Ken Lux on Feb 6, 2019
Latest reply on Feb 6, 2019 by Ken Lux

Using SW 2017 SP 5.0

 

I have a flow simulation completed and am trying to estimate what overall heat transfer coefficient flow sim is giving me for a finned surface. Unfortunately, I do not have a surface that has the correct cross-sectional area that I want to base my U on. (I tried adding a part that is just a surface to the assembly, but the surface plot failed - probably because the surface wasn't defined before the simulation was run.) So, I created a patterned point-parameter table w/100 points which I then filter out those points outside of the area of interest before taking an average of the heat flux in the y direction (in my model the y direction is perpendicular to the face I selected for the patterned point parameters).

 

However, I see that "Heat Flux (y)" is significantly different than "Surface Heat Flux". The ratio of "Heat Flux (y)" to "Surface Heat Flux" varies from 6.8 to 798!! All points being considered are points on the face of a solid in contact with another face.

 

From the help file:

Surface Heat Flux "...is the heat flux either on the solid-fluid surfaces or on the solid-solid surfaces. The heat flux values are positive if the heat exits the solid body that contains the face you selected and negative if the heat enters this solid body."

 

So "Heat Flux (y)" should be identical to "Surface Heat Flux". Why is it not?

 

One clue is that for these points, which again, are all listed as solid points, not solid-fluid points, I see that "Surface Heat Flux (Conductive)" is blank and "Surface Heat Flux (Convective)" is identical to "Surface Heat Flux". How in the world do you have purely convective heat transfer at a surface that is not in contact with a fluid?!?!?

 

Here is one such point - Anyone know why

  1. "Heat Flux (y)" doesn't match "Surface Heat Flux"
  2. "Surface Heat Flux (Conductive)" is empty for a point on the interface between two solids?
  3. "Surface Heat Flux (Convective)" is non-zero when there is no fluid in contact with the point?

 

    

 

Heat
  Flux [W/m^2]
Heat Flux (X)
  [W/m^2]
Heat Flux (Y)
  [W/m^2]
Heat Flux (Z)
  [W/m^2]
Surface Heat
  Flux [W/m^2]
Surface Heat
  Flux (Conductive) [W/m^2]
Surface Heat
  Flux (Convective) [W/m^2]
28707.6525-18920.5666112760.13769-17416.09477-458.4708145 -458.4708145

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