November 8, 2018 at 12:05 pmgiovanni_ianzitiSubscriber
Hello to everyone,
I`m working on a multiphase model of an heat pipe. In the closed volume I have 0.13 of liquid water and 0.87 of mixture (vapour+air).I`ve create the mixture with species transport model, because I`ve mass transfer between water liquid and vapour.
How many phases I must to use? Two: one for liquid and one for mixture? Or is better three phases: water, vapour and air?
November 8, 2018 at 5:18 pmRobAnsys Employee
You need one phase for the water and a second phase for the species mixture.
November 13, 2018 at 10:48 amRobAnsys Employee
Yes, if you set the gas phase using the species you have above, and then you can either set the mixture properties as constant or volume (or mass) weighted. For cp use a polynomial if that's what the paper recommends: I'd be slightly wary of this as it'll also depend on the composition, but that may be accounted for as temperature & vapour volume fraction will correlate.
November 13, 2018 at 10:51 am
November 13, 2018 at 10:54 amgiovanni_ianzitiSubscriber
But I can`t assign to the mixture a constant density, the other properties yes but not the density.
The phases for you are :
second phases: vapour,air and mixture
Because I need mixture in the phases if I want create species transport.
November 13, 2018 at 12:17 pmDrAmineAnsys Employee
For density either you use an EOS (Equation of State) or harmonic law or UDF. So your secondary phase is the "Mixture" with two "components": Air and Vapor.
November 13, 2018 at 1:11 pm
November 13, 2018 at 1:13 pmgiovanni_ianzitiSubscriber
Can you explain in details how to insert the missing properties in the mixture (density,molar mass and enthalpy) please?
thank you very much
November 13, 2018 at 1:48 pmDrAmineAnsys Employee
Molar mass will be just mile fraction time the molar mass of the component so it is done automatically. For others you can use mass-weighted mixing, ideal-mixing-law or just use constant at first.
November 13, 2018 at 1:50 pmRobAnsys Employee
Ah, easy one when you know!
Change the mixture density to volume weighted and press Change/create. Then go to the species and add the density you want for each. The solver is fairly intelligent in only asking for data that's needed, but can be a little confusing if you don't know the hierarchy in which things are set.
Enthalpy is only available when you turn on the evaporation/condensation models or set up mass transfer.
April 2, 2020 at 5:09 pmAjayc1160Subscriber
I would like to simulate condensation of mixture of air and water vapor. I would like to enter specific volume fractions of air and water vapor at the inlet.
When i choose mixture model in ansys, i m unable to enter specific volume fraction values. When i choose species transport, I am unable to enter condensation phenomena . What am i doing wrong here?
April 2, 2020 at 5:15 pmDrAmineAnsys EmployeePlease open a new thread for your question.
- You must be logged in to reply to this topic.
Earth Rescue – An Ansys Online Series
The climate crisis is here. But so is the human ingenuity to fight it. Earth Rescue reveals what visionary companies are doing today to engineer radical new ideas in the fight against climate change. Click here to watch the first episode.
Subscribe to the Ansys Blog to get great new content about the power of simulation delivered right to your email on a weekly basis. With content from Ansys experts, partners and customers you will learn about product development advances, thought leadership and trends and tips to better use Ansys tools. Sign up here.
- Suppress Fluent to open with GUI while performing in journal file
- Floating point exception in Fluent
- What are the differences between CFX and Fluent?
- Heat transfer coefficient
- Getting graph and tabular data from result in workbench mechanical
- The solver failed with a non-zero exit code of : 2
- Difference between K-epsilon and K-omega Turbulence Model
- Time Step Size and Courant Number
- Mesh Interfaces in ANSYS FLUENT
- error in cfd post
© 2023 Copyright ANSYS, Inc. All rights reserved.