Week 3 Challenge : CFD meshing on Turbocharger

Objective – CFD meshing on turbocharger

Introduction - In an internal combustion engine, a turbocharger is a forced induction device that is powered by the flow of exhaust gasses.

Here we are going to perform a CFD analysis over the 3-D model turbocharger by the use of ANSA V 22.1.3.

Procedure – To perform the CFD analysis over the turbocharger we need to follow these 3 simple step

1. Topo, clean up
2. Surface meshing
3. Volumetric meshing

• For the topo clean-up first check for the surface overlap, it can be seen by the two colour glitch.
• Check for the single coons, patch the open surface.
• Cut down the small surface.
• Check for the triple coons now, if any triple con is necessary keep it, and if it can be converted into double coons do it by using trip, topo, intersect commands.
• Trip> face> intersect> select first group of surface extended from its limit> separate now.
• Delete> select> middle click.
• Cons> release> will release the triple coons to two double coons.
• Delete the extra hot point.
• Topo> select the part> middle click> will connect the surface with the cut and will again convert the cons to the double coons.
• Middle click on any pop up to minimise it
• Inot > opposite of not.
• Auxiliaries> fine>will smooth the projection.
• Release and Topo are opposite to each other.
• Throughout the shaft there must be single hole.
• Check from the geometry all the single cons, sharp edges, patch, surface overlap and glitches must not be presented there.
• Run the execute to move on the next step.

Step_2 –  2-D element > tri element called surface mesh.

• Assign all the elements with different PID’s and different colours.
• All the inlet, outlet , impeller, shaft, rotor and casings are assigned with different PIDS
• Now start with the surface mesh and assign the target, max and min length accordingly given
• Blade stage_1 = 1mm
• Blade stage_2 = 1mm
• Impeller = 2mm
• Shaft rotor = 1mm
• Turbo casing = 5mm
• Compressor casing = 5mm
• Inlet casing cover = 5 mm
• Assign with the mesh quality accordingly.
• Right click + shift to deselect.
• IN 2-D showing sheet here, until show solid/ volume in 3-D
• Cut> macro> reconstruct> parametric.

Step_3 volumetric mesh

• Check first each and every possible part are surfaced meshed properly.
• Check there should not be any unmeshed surface.
• Then only we will continue in the volumetric mesh.
• Volume> define> whole DB> need to ensure surface mesh is performed or not.
• Now as all the elements are now assigned to the different volumes, we need to select the only component here in which fluid is going through, the elements having some thickness need to be deleted, as they are of no use.
• Select the volume> Remesh> select> CFD tetra.
• Will take some time and now all the components are 3-D meshed with different volumes.

Result- result images and zip file of ansa extension is attached below, please inspect carefully and give feedback accordingly.

Learning outcome- Here I learned about the volumetric mesh which can be only performed after the surface meshing, also as the turbocharger has a lot of different components having multiple and bulky design, topo clean-up was little bit challenging here and I got to know about  the different tools and process which can be used here to do the work. 

Conclusion – Turbocharger is the important auxiliary equipment of the IC engine and also its working consist with many different rotating parts, also as it works by the use of high pressurised exhaust gases, performing its mesh is quite a challenging part, identifying the different component according as the inlet and outlet and assign different parts with different target length will be the good learning here.