MODELLING AND SIMULATION OF FLOW THROUGH FLOWBENCH

AIM

To create a 3D model of a flow bench and run flow analysis

OBJECTIVES

• To perform Grid Dependence Test.
• To show the effect of valve lift on mass flow rate.
• Plot the graph between Lift vs Mass flow rate

THEORY

An air flow bench is a device used for testing the internal aerodynamic qualities of an engine component. It is primarily used to test the intake port and exhaust port of cylinder head of an IC engine.

In this project we are going to compare the effect of mass flow rate for different positions of valve lift.

PROCEDURE

• Draw the cylinder with diameter 50mm using circle command.
• Select Extrude in the features dialog box and extrude it up to 100mm.
• Construct the inlet flow pipe using the sweep command.
• Use shell command and give the thickness as 1mm in order to make the flow bench hollow.
• Create a new axis by selecting cylindrical face and select the face where the inlet valve as to be constructed.
• Give the dimensions for the valve then use revolve command. For axis of rotation select the newly created axis from the previous step.
• Create lids on both the sides by selecting the lid command in order to make the setup water tight.

The following are the 3D CAD models of the flow bench

3D MODEL

SECTION VIEW

FLOW STIMULATION SETUP

• Enable Flow Stimulation by selecting it from Soildworks-Add ins.
• Create a new project by selecting the wizard
• Give the name for the project and click next.
• Specify the unit system and click next.
• In analysis time select Internal flow and select next.
• In default fluid dialog box, select air as the fluid medium. Click Add and click next.
• Specify the wall conditions and click on Finish.
• Select the global mesh and specify the initial level of mesh.
• Select on Cut-plots and specify the contour as velocity and place the cut plot in desired location.
• Click on global goals and select mass flow rate. Click on surface goals and specify the contour as mass flow rate. Select the required surface and click ok.
• Run the stimulation.
• Click on new parametric study and run the stimulation for various levels of mesh for grid dependency test.
• A new parametric study is again started after finding the best mesh size. Specify the input variables. In add dimension parameter select the dimension where the valve is to be varied for different positions.
• In output variables select the cut plots and surface goals.
• Select scenario, copy and paste the design point 1 parameters 7 times. Specify the dimension for which how the valve lift is to be varied. This can also be done using range with numbers or range with steps from the input variable dialog box.

GRID DEPENDENCY TEST

Grid dependency test is usually performed to select the best mesh by varying the initial level of mesh. In this project, the grid dependency test is performed for mesh size like 3, 5 and 7. The valve is in open position at a distance of 1mm.

The following are the results of velocity plots obtained from grid dependency test.

GRID SIZE 3

GRID SIZE-5

GRID SIZE-7

The following table shows the mass flow rate for various levels of mesh

The mass flow rate varies for different levels of mesh. Higher the mesh size more accurate is the result. This project is carried out with the initial mesh size as 7.

VELOCITY PLOT FOR DIFFERENT VALVE POSITION

The position of the valve is varied from 1mm to 8mm. The following are the velocity plots obtained for different valve position.

VELOCITY PLOT AT 1mm

VELOCITY PLOT AT 2mm

VELOCITY PLOT AT 3mm

VELOCITY PLOT AT 4mm

VELOCITY PLOT AT 5mm

VELOCITY PLOT AT 6mm

VELOCITY PLOT AT 7mm

VELOCITY PLOT AT 8mm

The following table displays the mass flow rate at different positions

The negative sign in mass flow rate denotes that the mass is leaving out from the system.

PART DRAWING

https://drive.google.com/file/d/1drHCMn-lCjpnVzmWD88FVpmf1JMa6jZ0/view?usp=sharing

RESULTS

• A 3D model of a flow bench is created and flow stimulation is successfully carried out.
• As the valve lift increases, the mass flow rate coming out from the outlet also increases.
• The velocity at the inlet of the valve also increases with increase in lift parameter.