[aja1345]

Hi,


I am simulating a water hydraulic poppet valve in order to investigating cavitation phenomenon in that. Also, I am using a paper for verification of this simulation.



Model is 2D, axisymmetric. Mesh is generated by Gambit software. In order to improve the quality of the mesh, the simulated model is divided into three parts(please see the following picture). Part 1 and part 3 are discretized by using map method, and part 2 is discretized by utilizing pave method. According to the paper, The mesh quality of part 2 has a significant effect on the results accuracy due to the high Reynolds number in this part.





My model:





My mesh:





BC is as follows in my work:












How can set "Interracial area concentration"? this is defualt value(0.0001).








here, the value of diameter is default value. I think that this value should change in this simulation. but How value?

Value of pressure contour is good agreement with the paper result. therefore, My result:

and paper result:

when i display vapor volume fraction in Ansys Fluent, I see the vapor in the specified part from the following figure. Location of vapor formation in my result is same with that of that in paper results. But I have a problem with value of vapor fraction contour and the value of my result is greater than value of the paper(please see the following pictures) Why does this happen?


My result:





Paper result:









Thanks.

[aja1345]

Magnify the My mesh in part2:







Residuals are as follows:



More decrease of residuals is not very effect on the result, especially in vapor volume fraction. According to above picture, IAC (Interfacial area concentration) have not good convergence and this is a problem!!!


There is the following BCs in the paper:





The inlet pressure is increased gradually to 14 MPa (14 MPa is the maximum pressure that provided by the pump in the experiment), and the outlet pressure is kept at the atmospheric pressure (gauge pressure is zero in this paper) or increased gradually from 0 to 12 MPa.

[aja1345]

No one help?