bubble model

shahin.59 · July 15, 2009, 02:39

I am working on modeling and simulation of film boiling formation on hot rod when submerging in water. I use flow3d models so that use the adiabatic bubble model with heat and mass transfer. through, I use Clausius-Clapeyron model and found thermodynamic data which need for this model such water saturated pressure, latent heat vapor, accomodation coefficient and etc. then i enable the cavitation model for initiation of bubble, the result of model processing is not logical. For example the bubbles form an different place, but we excepted that bubble form only on hot surface of rod, also the pressure was not logical. I think there are any problem in cavitation properties in physics section also I have not confident on accomodation coefficient (I examined with 0.1 and 0.05 values). Would you please guide me for this problem and where are there any mistake for this model.

stefmascio · July 16, 2009, 11:00

the "thermal bubble with phase change" model would probably work better than the cavitation one.
I think the cavitation model generates the bubbles only where the pressure is below the cavitation pressure that you give, without looking at the temperature.

shahin.59 · July 16, 2009, 11:08

the "thermal bubble with phase change" can't simulate the initiation of bubble formation, we want model generation of bubble in a hot rod.
what can we do?

stefmascio · July 20, 2009, 11:17

I think the "thermal bubble" is a good model to simulate that. Many companies use it to model thermal bubbles in inkjet printers, where the bubble of air is generated inside the fluid starting from a hot surface.
But maybe somebody other more expert in inket simulation can confirm this.

July 15, 2009, 02:39	bubble model	#1
shahin.59 New Member shahin Join Date: Apr 2009 Posts: 8 Rep Power: 17	I am working on modeling and simulation of film boiling formation on hot rod when submerging in water. I use flow3d models so that use the adiabatic bubble model with heat and mass transfer. through, I use Clausius-Clapeyron model and found thermodynamic data which need for this model such water saturated pressure, latent heat vapor, accomodation coefficient and etc. then i enable the cavitation model for initiation of bubble, the result of model processing is not logical. For example the bubbles form an different place, but we excepted that bubble form only on hot surface of rod, also the pressure was not logical. I think there are any problem in cavitation properties in physics section also I have not confident on accomodation coefficient (I examined with 0.1 and 0.05 values). Would you please guide me for this problem and where are there any mistake for this model.

July 16, 2009, 11:00		#2
stefmascio Member Stefano Join Date: Mar 2009 Posts: 59 Rep Power: 17	the "thermal bubble with phase change" model would probably work better than the cavitation one. I think the cavitation model generates the bubbles only where the pressure is below the cavitation pressure that you give, without looking at the temperature. 6863523 likes this.

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July 16, 2009, 11:08		#3
shahin.59 New Member shahin Join Date: Apr 2009 Posts: 8 Rep Power: 17	the "thermal bubble with phase change" can't simulate the initiation of bubble formation, we want model generation of bubble in a hot rod. what can we do?

July 20, 2009, 11:17		#4
stefmascio Member Stefano Join Date: Mar 2009 Posts: 59 Rep Power: 17	I think the "thermal bubble" is a good model to simulate that. Many companies use it to model thermal bubbles in inkjet printers, where the bubble of air is generated inside the fluid starting from a hot surface. But maybe somebody other more expert in inket simulation can confirm this.