[ICEM] how to improve hexa mesh quality?

MatJo · May 16, 2014, 11:38

hi everyone,

Right now i doing my final year project, i doing the scavenging simulation process and for my model, i use ICEM for meshing. I still new in ICEM, i hope someone can help me to improve my model mesh. Right now my model cannot run a simulation in fluent, someone told me to ask this forum, maybe there is something wrong on my model mesh, hope someone can help me, please

(sorry for bad english)

https://www.mediafire.com/?dg72rz80p19vnd6

this is my model ICEM file, hope you guy can look onto it

bluebase · May 23, 2014, 12:04

Hi MatJo,

your target is to simulate a piston engine, isn't it?

The main cause of problems seems to be the geometry. There are a lot of junctions of geometric entities which do not match. See the following pictures. For example, the duct's fillet jumps from a big radius to a smaller one (first picture). Also check the source of your geometry/CAD data. the smaller ducts seem to be not proper attached to the main cylinder(2nd picture). Is that desired?

junction.jpg junction2.jpg

The geometry the way it's now seems to need lots of work to be cleaned. Firstly, I would suggest you to simplify your geometry, not in ICEM but in a CAD program. ICEM has all the neccessary tools too, but i guess you might be faster using CAD.

Only after you cleaned your geometry you can redo your mesh. To do so, please redo the tutorials of ICEM, especially the Hexa Mesh Tutorials for a 2D and 3D Pipe Junction. Also the sphere cube geometry tutorial can't hurt.
There is one big flaw in your mesh right now. It's visible in the following picture. You always create an additional block to cover the junction of different duct cross sections. That way you will have very thin and distorted elements which self-intersect. You will have to eradicate all those blocks and patch through the topology of the block structure like it is done in the tutorials. Maybe start with blocking just one duct at a time.
junction-vs-patch.jpg

With regards,
Sebastian

MatJo · May 28, 2014, 20:49

Hi Sebastian,

thank you for you help and tips, i will try to follow your suggestion, i really appreciate your help,

May 16, 2014, 11:38	how to improve hexa mesh quality?	#1
MatJo New Member Join Date: Feb 2014 Posts: 5 Rep Power: 12	hi everyone, Right now i doing my final year project, i doing the scavenging simulation process and for my model, i use ICEM for meshing. I still new in ICEM, i hope someone can help me to improve my model mesh. Right now my model cannot run a simulation in fluent, someone told me to ask this forum, maybe there is something wrong on my model mesh, hope someone can help me, please (sorry for bad english) https://www.mediafire.com/?dg72rz80p19vnd6 this is my model ICEM file, hope you guy can look onto it

May 23, 2014, 12:04		#2
bluebase Senior Member Sebastian Engel Join Date: Jun 2011 Location: Germany Posts: 567 Rep Power: 21	Hi MatJo, your target is to simulate a piston engine, isn't it? The main cause of problems seems to be the geometry. There are a lot of junctions of geometric entities which do not match. See the following pictures. For example, the duct's fillet jumps from a big radius to a smaller one (first picture). Also check the source of your geometry/CAD data. the smaller ducts seem to be not proper attached to the main cylinder(2nd picture). Is that desired? junction.jpg junction2.jpg The geometry the way it's now seems to need lots of work to be cleaned. Firstly, I would suggest you to simplify your geometry, not in ICEM but in a CAD program. ICEM has all the neccessary tools too, but i guess you might be faster using CAD. Only after you cleaned your geometry you can redo your mesh. To do so, please redo the tutorials of ICEM, especially the Hexa Mesh Tutorials for a 2D and 3D Pipe Junction. Also the sphere cube geometry tutorial can't hurt. There is one big flaw in your mesh right now. It's visible in the following picture. You always create an additional block to cover the junction of different duct cross sections. That way you will have very thin and distorted elements which self-intersect. You will have to eradicate all those blocks and patch through the topology of the block structure like it is done in the tutorials. Maybe start with blocking just one duct at a time. junction-vs-patch.jpg With regards, Sebastian diamondx and MatJo like this. Last edited by bluebase; May 29, 2014 at 11:25.

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May 28, 2014, 20:49		#3
MatJo New Member Join Date: Feb 2014 Posts: 5 Rep Power: 12	Hi Sebastian, thank you for you help and tips, i will try to follow your suggestion, i really appreciate your help,