January 16, 2023 at 9:08 pminouzilSubscriber
I want to simulate a minimum quantity lubrication process and am using the DPM model in fluent. I want to include the affect of vaporization of the oil droplet and therefore have used the species transport model. below image shows the species dialogue inputs:
The injection input for the base oil is as shown below:
My question is, since I have specified the mass flow rate for the oil through the DPM dialogue, what input do I give for the species mass fraction at the inlet? Should I just keep it as zero?
January 17, 2023 at 7:49 amDrAmineAnsys Employee
You should provide the mass fractions corresponding to your inflow gas. I assume you have Air coming in: then provide the air mass fraction composition. Aslo you defined 5 components but you did only show 4: what is the fifth one?
January 17, 2023 at 4:55 pminouzilSubscriber
Thank you for the support. Really appreciate the quick answer. Air was the fifth one. Since I have its component species already defined in the template, I removed air. That is the correct way to go? The outlet species fractions I kept same as the inlet.
January 18, 2023 at 6:46 amDrAmineAnsys Employee
How many species do you have now? What is the abundant specie? At your inlet you are prompted to provide 4 Components Mass Fractions which is wrong if you have only 4 components.
If you do not know what is outside then just the outlet species which might correspond to most realistic composition whenever a "theoretical" or "phyiscal" reversal flow can occur.
January 20, 2023 at 11:10 pminouzilSubscriber
Following are the species now defined: h20, N2, O2, baseoil (liquid oil). I selected nitrogen as the abundant specie (last specie). At the inlet I am prompted to enter mass fraction for all components except nitrogen. I chose nitrogen as the abundant specie since air has very high mass flow rate compared to oil. Below is an image of the inlet boundary condition:
Since there are no reactions at the inlet (or no gaseous phase of oil at inlet), I keep the mass fractions as zero. Is that right?
And at outlet if I input mass fractions as zero, it would mean no reverse flow at the outlet?
Thank you for the assistance.
January 23, 2023 at 6:34 amDrAmineAnsys Employee
If you are assuming that only N2 is entering at inlet then it is correct. If you are not expecting that only N2 will flow in then you need to provide the right mass/mole fraction of the composition.
At the outlet if you input the same as now at your inlet this will mean that in case of reversal flow only N2 will enter from the outlet. Default Pressure Outlet in Ansys Fluent is acting as an Opening: it allows inflow and outflow.
- 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.