Week 2 Challenge : Surface meshing on a Pressure valve
AIM:
- To check for geometrical errors and perform Topology cleanup accordingly.
- To perform surface wrap on the given automotive assembly.
- Make a volumetric mesh in the given geometry, then make a surface mesh so we can proceed with the volumetric mesh, and finally select the required volumes and create a volumetric mesh in those volumes.
PROBLEM STATEMENT:
- Create a Watertight Model for The CFD Simulation using ANSA
- The model should be simplified According to the flow Analysis Application
- All the geometry features should be captured properly
- Surface mesh using Tria elements, Skewness < 0.6
- No Intersection Errors
- 5 layers of Prism Mesh
- Volumetric mesh using tetrahedral elements
Software Used:
- ANSA v22.1.0.
INTRODUCTION:
RECEIVED MODEL: ENGINE ASSEMBLY OF TWO-STROKE ENGINE.
LITERATURE REVIEW:
- Gone through various research papers to study the various element size for meshing different parts.
- Also, to do a study of prism mesh and volumetric mesh. I have attached the research papers with the report file.
Two-Stroke Engines: Defining Their Purpose:
In a four-stroke engine, each of the four essential steps of the power-producing cycle is given its piston stroke:
1) Compression
2) Power
3) Exhaust
4) Intake
AIM:
- To check for geometrical errors and perform Topology cleanup accordingly.
- To perform surface wrap on the given automotive assembly.
- Make a volumetric mesh in the given geometry, then make a surface mesh so we can proceed with the volumetric mesh, and finally select the required volumes and create a volumetric mesh in those volumes.
PROBLEM STATEMENT:
- Create a Watertight Model for The CFD Simulation using ANSA
- The model should be simplified According to the flow Analysis Application
- All the geometry features should be captured properly
- Surface mesh using Tria elements, Skewness < 0.6
- No Intersection Errors
- 5 layers of Prism Mesh
- Volumetric mesh using tetrahedral elements
Software Used:
- ANSA v22.1.0.
INTRODUCTION:
RECEIVED MODEL: ENGINE ASSEMBLY OF TWO-STROKE ENGINE.
LITERATURE REVIEW:
- Gone through various research papers to study the various element size for meshing different parts.
- Also, to do a study of prism mesh and volumetric mesh. I have attached the research papers with the report file.
Two-Stroke Engines: Defining Their Purpose:
In a four-stroke engine, each of the four essential steps of the power-producing cycle is given its piston stroke:
1) Compression
2) Power
3) Exhaust
4) Intake
- While the piston is near Bottom Dead Center, the mixture continues to move from the crankcase, up through the transfer ports, and into the cylinder. As the piston rises, it first covers the transfer ports, leaving only the exhaust port still open. If there were no way to stop it, much of the fresh charge would now be pumped out of the exhaust.
- But there is a simple way to stop it—using exhaust pressure waves in the exhaust. If we shape and dimension the exhaust pipe right, a reflection of the original pressure pulse, generated as the exhaust port opened, will bounce back to the port just as a new charge is being pumped out of it. This pressure wave stuffs the fresh charge back into the cylinder just as the rising piston covers the exhaust port.
- Because the fuel-air mixture is constantly being pumped by the crankcase, it is not practical to lubricate the piston and crank with pumped circulating oil—it would be swept away by the mixture rushing in and out. Therefore, we must either mix a little oil with the fuel (2 to 4 per cent) or inject it very sparingly into the bearings with a tiny metering pump. The fact that there is so little oil dictates that such simple two-stroke engines must employ rolling bearings, whose need for oil is minimal.
- More complicated two-stroke exist. Instead of using the crankcase and underside of the piston as a fresh-charge pump, we can use a separate rotary blower, directly connected to the transfer ports in the cylinders. We don't have to place the exhaust port in the cylinder wall—it can take the form of four overhead poppet exhaust valves, as it does in two-stroke marine, rail, and truck diesel. Because such engines do not use their crankcases as fresh charge pumps, they can employ long-lasting plain bearings, lubricated conventionally by pumped recirculating oil.
- Two-stroke diesel is scavenged with pure air, not a fuel-air mixture. Their fuel is injected only after all ports have closed, preventing loss. Certain crankcase scavenged two-strokes do the same, and are called “DI,” or Direct Injection two-strokes. They can be made as fuel-efficient and low in exhaust emissions as four-strokes.
- The world’s most efficient piston engines are in fact the giant, slow-turning marine diesel that carries the world’s international shipping trade—they are twice as efficient as the usual four-stroke spark-ignition engines found in cars and motorcycles.
PROCEDURE:
Watertight Model (SURFACE WRAP):
- To create a Watertight Model for The CFD Simulation using ANSA.
- Open the geometry in the ANSA software. Clean up the surface of the geometry by deleting unwanted parts and faces present on the geometry. As surface wrapping is generally carried out to study the flow over a surface So the main importance should be outside surface rather inside parts and surface.
- Close all the holes present in the geometry otherwise while wrapping it might create disturbances. The below diagram shows the final geometry before assembly.