help on phase change model needed

richard2000 · March 1, 2013, 12:50

I am doing a melting/solidification model using homogeneous binary mixture in CFX. I specified the material specific reference enthalpy per the latent heat and the momentum source in terms of Darcy equation for porous media as a function of velocity and mass fraction. The results I got always show a very low flow velocity on the order of about 1mm/s rather than about 100 mm/s in reality. I tried different momentum source terms or even nothing at all, and the flow velocity increases slightly but still on the order of mm/s. I have found papers using similar models although no details are inclded. What could I have done wong? I have been struggling with this for a long time. Your help is highly appreciated!

Best regards,

Richard

ghorrocks · March 3, 2013, 06:31

Melting/solidification models are very complex and hard to run. There is no way based on the sketchy information you describe anybody can debug that. In fact debugging complex models like this takes a long time and a lot of patience and skill.

Other than the general advice here I cannot help much: http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F

March 1, 2013, 12:50	help on phase change model needed	#1
richard2000 New Member Join Date: Sep 2010 Posts: 6 Rep Power: 16	I am doing a melting/solidification model using homogeneous binary mixture in CFX. I specified the material specific reference enthalpy per the latent heat and the momentum source in terms of Darcy equation for porous media as a function of velocity and mass fraction. The results I got always show a very low flow velocity on the order of about 1mm/s rather than about 100 mm/s in reality. I tried different momentum source terms or even nothing at all, and the flow velocity increases slightly but still on the order of mm/s. I have found papers using similar models although no details are inclded. What could I have done wong? I have been struggling with this for a long time. Your help is highly appreciated! Best regards, Richard

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March 3, 2013, 06:31		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	Melting/solidification models are very complex and hard to run. There is no way based on the sketchy information you describe anybody can debug that. In fact debugging complex models like this takes a long time and a lot of patience and skill. Other than the general advice here I cannot help much: http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F