Learning Forum

[Ashi_Chauhan]

I have a question about the evaporation-condensation, Lee model. It is a release of liquid hydrogen (LH2) in the air medium where the temp. is 283.56K, LH2 release temp is 20and saturated temperature is 20.324K. I am using the Multiphase mixture model with energy and K-E model and mass species transfer from hydrogen-air (hydrogen, nitrogen & oxygen). I am having an error of negative latent heat transfer and simulations couldn't continue. Could you please tell me where I am wrong and how to correct this error?                                                                                                                                                                                                                                                                                                                                                                                                   

[Rob]

If you check the material properties are the reference enthaplpy temperatures the same, and if so what is the latent heat? n

[Ashi_Chauhan]

Thank you Rob for your comment, I checked the material properties of hydrogen gas and liquid hydrogen and the standard state enthalpy is zero for both cases. Why is that? and is it because that latent heat is less than zero?nn

[Rob]

It means we didn't have the data when the materials were defined; the Fluent database can have missing entries and all values should be checked before running the model. If you find the latent heat and add it to one or other material (use + or - to suit) that should solve the problem. n

[Sree Kumaran]

Hello rob i am working on simulation of solar still when i initialise in ansys 2020 and lesser version it is initialising properly but newer version give me latent heat error while initialisation please help me what i should change . Currently i change only the density for the water and vapour. I even tried changing sse of water to zero and vapour to some 4e07 i guess some value from other forums