|
[Sponsors] |
November 6, 2017, 10:26 |
sealing and two-stroke gas flow question
|
#1 |
New Member
hyhui
Join Date: Jul 2017
Posts: 19
Rep Power: 8 |
Hello everyone,
I am simulating gas flow of a two-stroke engine,and i use the "seal" option to make the scavenge port and exhaust port be sealed. The question is below: When i start my simulation from TDC to BDC , a little gas in cylinder leak to intport and outport at the moment i start it. I guess the gap between piston and linear is too big, so i set the gap from 0.05mm to 0.01mm. But the mass of the leakage is similar. Then , i don't know how to solve this problem. Is someone met the same question? |
|
November 8, 2017, 11:48 |
|
#2 |
Member
Tristan Burton
Join Date: Sep 2017
Posts: 92
Rep Power: 8 |
Hello,
Have you looked at a clip plane to verify that the sealing is working properly to cut off the ports from the combustion region? The attached image shows the difference between a sealed and unsealed cylinder. Best regards, Tristan |
|
November 9, 2017, 01:05 |
|
#3 | |
New Member
hyhui
Join Date: Jul 2017
Posts: 19
Rep Power: 8 |
Quote:
i have cut the clip plane in the attached file, the seal is normal, but there are some high temperature gas in the ports. the red color represent the temp. I don't know how the high temperature come to the ports after sealing. |
||
November 9, 2017, 13:33 |
|
#4 |
Member
Tristan Burton
Join Date: Sep 2017
Posts: 92
Rep Power: 8 |
Hello,
Ok, it's a region assignment problem. The cells near the port seals are getting assigned to the cylinder region instead of the appropriate port region, and they're getting initialized with the conditions of the cylinder. Can you try switching the region assignment for the piston skirt and the liner to 'Dependent'? Best regards, Tristan |
|
November 10, 2017, 09:09 |
|
#5 | |
New Member
hyhui
Join Date: Jul 2017
Posts: 19
Rep Power: 8 |
Quote:
Thanks for your help, i switch the piston skirt ,liner, and ring into 'dependent', it works at the begining. But there comes to an WARNING: "flow is occuring between regions which are not geometrically connected. This indicates that the cell resolution in this area is not sufficient to resolve all regions. Flows output in regions_flow.out may not balance" , when the port open. Finally, it aborted with the message: stuck in an infinite loop trying to initialize region_id for cells, cell count is 4 stuck in an infinite loop trying to initialize region_id for cells, cell count is 4 stuck in an infinite loop trying to initialize region_id for cells, cell count is 2 stuck in an infinite loop trying to initialize region_id for cells, cell count is 2 internal error: stream numbers do not match; Can you tell me what should i do for it ? Thank you very much! Sincerely. YHY |
||
November 13, 2017, 01:43 |
|
#6 | |
New Member
hyhui
Join Date: Jul 2017
Posts: 19
Rep Power: 8 |
Quote:
I haven't find the way to solve it yet. Can you help me again? Thank you very much! Sincerely! hyhui |
||
November 13, 2017, 11:45 |
|
#7 |
Member
Tristan Burton
Join Date: Sep 2017
Posts: 92
Rep Power: 8 |
Hello,
Have you checked your surface file in Studio to make sure that the triangles are assigned to the correct boundary group and that the boundary groups are assigned to the appropriate region? One thing that can help is to check the Group color by regions box in the View Options dock and make sure that everything looks ok as you turn the boundary groups in the different regions on and off. Best regards, Tristan |
|
November 14, 2017, 09:44 |
|
#8 | |
New Member
hyhui
Join Date: Jul 2017
Posts: 19
Rep Power: 8 |
Quote:
Thanks for your patient help! I may have solved the problem, when i encryption the grid around the port, it also have the warning above, but it can finish normally. Sincerely! hyhui |
||
April 17, 2023, 06:58 |
|
#9 | |
New Member
WK
Join Date: Feb 2023
Posts: 2
Rep Power: 0 |
Quote:
I am also having problem with sealing and want to visualize the region just as you and Hyhui attached in this post. How can I see the regions, not the surfaces in that way in Studio? |
||
|
|