Calculating Convection and Diffusion

wadeellis · September 28, 2015, 15:21

Hello,

I using Star-CCM+ to simulate the flow of hot (750 C), pure helium out of a small (2 mm ID) hole into room temperature air at atmospheric pressure. My question is whether there is a way to tease out convection and diffusion information for helium into air and air into helium.

Thank you.

me3840 · October 5, 2015, 20:30

I don't understand the question. Tease out?

wadeellis · October 5, 2015, 20:59

Sorry, I was trying to ask if there is a way to obtain numerical values for the convection and diffusion. For instance, you can export the values for temperature, velocity, mass fraction, etc. Is there a similar way to export convection and diffusion information?

me3840 · October 5, 2015, 21:31

Shouldn't you be able to just make field functions for these? Maybe:
U-convection: div($Density*$$Velocity[0]*$$Velocity)
U-diffusion: div($DynamicViscosity*grad($$Velocity[0]))

wadeellis · October 6, 2015, 12:14

Thank you for that suggestion. I have not done much with field functions yet. I will look into them and see if they will help me solve the problem I am working on.

September 28, 2015, 15:21	Calculating Convection and Diffusion	#1
wadeellis New Member Wade Join Date: Jul 2015 Posts: 24 Rep Power: 10	Hello, I using Star-CCM+ to simulate the flow of hot (750 C), pure helium out of a small (2 mm ID) hole into room temperature air at atmospheric pressure. My question is whether there is a way to tease out convection and diffusion information for helium into air and air into helium. Thank you.

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October 5, 2015, 20:30		#2
me3840 Senior Member Join Date: Nov 2010 Location: USA Posts: 1,232 Rep Power: 24	I don't understand the question. Tease out?

October 5, 2015, 20:59		#3
wadeellis New Member Wade Join Date: Jul 2015 Posts: 24 Rep Power: 10	Sorry, I was trying to ask if there is a way to obtain numerical values for the convection and diffusion. For instance, you can export the values for temperature, velocity, mass fraction, etc. Is there a similar way to export convection and diffusion information?

October 5, 2015, 21:31		#4
me3840 Senior Member Join Date: Nov 2010 Location: USA Posts: 1,232 Rep Power: 24	Shouldn't you be able to just make field functions for these? Maybe: U-convection: div($Density$$Velocity[0]$$Velocity) U-diffusion: div($DynamicViscosity*grad($$Velocity[0]))

October 6, 2015, 12:14		#5
wadeellis New Member Wade Join Date: Jul 2015 Posts: 24 Rep Power: 10	Thank you for that suggestion. I have not done much with field functions yet. I will look into them and see if they will help me solve the problem I am working on.