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-   -   how to model thermal bubble inkjet (http://www.cfd-online.com/Forums/flow-3d/109574-how-model-thermal-bubble-inkjet.html)

dwtme November 21, 2012 01:10

how to model thermal bubble inkjet?
 
HI everyone,
I want to model thermal bubble inkjet. i don't know how to heat the liquids and generate bubble. I have used the model: bubble and phase change,heat transfer, surface tension , viscosity and turbulence. In the boundary condition i use wall
->thermal information->power:5e8, but it doesn't work .Only a small region of liquid near the wall increase temperature and doesn't have any bubble or phase change. The liquid i use is water(CGS unit at 20C)
In the phase change, I input the data below:
saturation pressure:1e6
saturation temperature:373
latent heat of vapor:2.257e6
gamma:1.4
accomodation coefficient:0.1
vapor specific heat:6.67e6
exponent temperature:1.182e-4
superheat temperature:0

can somebody teach me how to set the accurate model to run thermal bubble inkjet simulation?

best reards
Tim

dwtme November 27, 2012 21:14

by the way, my edition is v9.3!

JBurnham December 4, 2012 19:58

If the water is not warming up, I would suggest checking the thermal property coefficients of the water itself (Fluid 1): liquid specific heat CV1, liquid thermal conductivity CHV1. Also set heat transfer coefficient between wall and fluid HWALL1.

dwtme December 12, 2012 23:05

Dear JBurnham,
Thanks for your reply. I still have some questions.
(1)Do I need to creat a component as a wall or use the boundary condition setting"wall", what is the difference?
(2)"The heat transfer coefficient between wall and fluid " means the heat conduction coefficient of wall or fluid? Or does it have other meaning?
Thanks,
Best regards
Tim

JBurnham January 7, 2013 13:33

You can use either a component or a wall-type boundary, it is up to you. The component may be easier to use. The component-to-fluid heat transfer coefficient is described in the User Manual in some detail, including the ways in which FLOW-3D picks a coefficient if one is not defined.


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