Modelling and simulation of flow through a flowbench

AIM:

• To create a 3d model of the flow bench and to perform flow simulation.
• To perform grid dependency test to check the accuracy of the grids.
• To perform flow simulation at different valve lifts.
• To plot the valve lift vs mass flow rate.

Introduction:

Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses numerical analysis and data structures to analyze and solve problems that involve fluid flows.

Air flowbench is a device used for testing the internal aerodynamic qualities of an engine component and is related to the more familiar wind tunnel.

It is used primarily for testing the intake and exhaust ports of cylinder heads of internal combustion engines. It is also used to test the flow capabilities of any component such as air filters, carburetors, manifolds or any other part that is required to flow gas. A flow bench is one of the primary tools of high performance engine builders, and porting cylinder heads would be strictly hit or miss without it.

3d model:

Grid dependency test:

Valve is placed at a fixed postion in all the below study points i.e 0.003 m

study point	1
Number of cells X	12
Number of cells Y	16
Number of cells Z	10
Refinment of cells	3

study point	2
Number of cells X	14
Number of cells Y	18
Number of cells Z	12
Refinment of cells	4

study point	3
Number of cells X	16
Number of cells Y	20
Number of cells Z	14
Refinment of cells	5

Velocity cutplot for refinment 5

Pressure cutplot for refinement 5

Based on the results of the grid analysis test study point 3 is producing most justifying results. Hence it is choosen for valve plot simulation.

Valve simulation:

Valve lift: 0.001mm(approx)

velocity plot at 0.001 mm

Pressure plot at 0.001mm

Valve lift 0.002 mm

velocity plot at 0.002 mm

Pressure plot at 0.002mm

Valve lift =0.003mm

velocity plot at 0.003 mm

Pressure plot at 0.003mm

Setup Explanation:

• 3d model of the flow bench is created.
• New wizard is created with internal simulation.
• Initial boundary condtions such as total pressure and static pressure is created.
• New parametric study is created by grid test.
• Simulation is carried and the obtained results are analyized and choose the best grid.
• Then adjust the valve lift and carry the simulation process.
• Obtain the cutplots for velcotiy and pressure.

Plots:

Valve lift vs Mass flow rate

Conclusion:

• As the valve lift increases the pressure at the inlet valve gets decreased.
• As the valve lift increases the flow of velocity across the valve lift gets increases.
• When the valve lift increases there will more amount of flow towards the cyclinder which decreases the pressure at the inlet.
• Thus the valve lift increases with the mass flow rate.