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-   -   Cavity air flow with radiation – result variable (http://www.cfd-online.com/Forums/cfx/21866-cavity-air-flow-radiation-result-variable.html)

Yingchun November 24, 2005 12:31

Cavity air flow with radiation – result variable
 
Hi all,

The test case I am looking at is: A long (8meter) and open ended square cavity (0.5 by 0.5 meter) with a hot surface (150C) and a cold surface (20C), the other two surfaces are adiabatic. I am using CFX5.7 run the simulations with radiation model and buoyancy. There is a list of variables in post and I am trying to figure out what kind of relationship between them under conditions above mentioned. For example, I can use an expression to get the area weighted variables " say 'areaAve<variable>@hotwall' The Variables are:

Heat Flux Incident Radiation Radiation Intensity Volumetric Absorbed Radiation Volumetric Emitted Radiation Wall Adjacent Temperature Wall Convective Heat Flux Wall Heat Flux Wall Heat Transfer Coefficient Wall Irradiation Flux Wall Radiative Heat Flux

What I got confuse are things like: the 'Heat Flux' is not actually equal to the 'Wall Heat Flux', is the 'Wall Heat Transfer Coefficient' the same as the convective heat transfer coefficient near wall (no this variable in post)? It seems the "Wall Convective Heat Flux = Wall Heat Transfer Coefficient * (Wall Boundary Temperature " Wall Adjacent Temperature)" not for the "Wall Heat Flux"

What these parameters stand for specifically at the 'Hotwall', and what are their relations? I mean for there area weighted values?

Thanks for your clarifications

Yingchun


Yingchun November 25, 2005 12:13

Re: Cavity air flow with radiation – result vari
 
Sorry, just noticed that the parameters listed there were not line by line as i expected, so paste here again.

The test case I am looking at is: A long (8meter) and open ended square cavity (0.5 by 0.5 meter) with a hot surface (150C) and a cold surface (20C), the other two surfaces are adiabatic. I am using CFX5.7 run the simulations with radiation model and buoyancy. There is a list of variables in post and I am trying to figure out what kind of relationship between them under conditions above mentioned. For example, I can use an expression to get the area weighted variables " say 'areaAve@hotwall' The Variables are:

Heat Flux

Incident Radiation

Radiation Intensity

Volumetric Absorbed Radiation

Volumetric Emitted Radiation

Wall Adjacent Temperature

Wall Convective Heat Flux

Wall Heat Flux

Wall Heat Transfer Coefficient

Wall Irradiation Flux

Wall Radiative Heat Flux

What I got confuse are things like: the 'Heat Flux' is not actually equal to the 'Wall Heat Flux', is the 'Wall Heat Transfer Coefficient' the same as the convective heat transfer coefficient near wall (no this variable in post)? It seems the "Wall Convective Heat Flux = Wall Heat Transfer Coefficient * (Wall Boundary Temperature " Wall Adjacent Temperature)" not for the "Wall Heat Flux"

What these parameters stand for specifically at the 'Hotwall', and what are their relations? I mean for there area weighted values?

Thanks for your clarifications

Yingchun



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