Calculating convective heat transfer with BOS

[Sadeghi6872]

Hi All,
Hope you are doing well. I have Background Oriented Schlieren images of the fire which give me the displacement field and want to calculate the convective heat flux. I wonder how I can go for this or if I can FDS.

I would appreciate any idea.

Best,
Mohamad

[Sadeghi6872]

Hi Again,

I am wondering if there is any way in FDS to have a 2-D contour of convective heat flux in a defined domain at the centerline of the test bed with Excelsior particles.

Thanks.

[mcgratta]

You need to be more specific. Do you want the convective heat flux to the ground? If so, you can use a boundary (BNDF) output for CONVECTIVE HEAT FLUX.

[Sadeghi6872]

Hi Kevin,

Thank you very much for the response. I need convective heat flux of the flame and plume region as a 2-D contour.

[mcgratta]

I still don't know exactly what you mean, but I will guess. Search for ENTHALPY FLUX Z in the User's Guide.

[Sadeghi6872]

Dear Kevin,

I apologize for any inconvenience and appreciate your feedback. I have added ENTHALPY FLUX to my FDS code with the following line:

    &DEVC ID='q-dot', XB=-1.8,0,0.5,0.5,0.1,1, QUANTITY='ENTHALPY FLUX Y', SPATIAL_STATISTIC='AREA INTEGRAL' /

This device produces a single data point for each time step, as seen in my _devc.csv file.

I currently use the following slice file to display a temperature contour on the midplane (y = 0.5):

    &SLCF PBY=0.5, QUANTITY='TEMPERATURE', VECTOR=T /

However, I now need a similar slice configuration to show the convective heat flux, and I am unsure how to proceed. I have attached my FDS code for your reference.

Thank you very much for your assistance.

Best regards,
Mohamad

Wind100.txt

[Vojta-Salek]

Hello, &DEVC always produces a single data output. Although the XB input is a plane, you call SPATIAL_STATISTIC='AREA INTEGRAL' and the results of the integral is a scalar (total heat transfer over the area).

If you need exactly the same slice file, why don't you analogically use &SLCF PBY=0.5, QUANTITY='ENTHALPY FLUX Z', VECTOR=T /?

You have a large and relatively complex simulation. I strongly recommend reading the User's Guide carefully, as it is always the user's responsibility to understand what FDS does.