Modelling and simulation of flow through a flowbench

Objective:

To create a 3D model of a flow bench and run flow analysis. You will be obtaining a plot of lift vs mass flow rate

• Grid dependence test.
• For three grids run your simulation at a particular valve lift and explain your results.
• Effect of valve lift on the mass flow rate.
• Once you have decided on the best grid, run a parametric sweep to show the effect of valve lift on the mass flow rate.

Description:

Modeling:

A model is a representation of something. It captures not all attributes of the represented thing, but rather only those seeming relevant. The model is created for a certain purpose and stakeholders.

Simulation:

A simulation is an approximate imitation of the operation of a process or system; that represents its operation over time. Simulation is used in many contexts, such as simulation of technology for performance tuning or optimizing, safety engineering, testing, training, education, and video games.

Flowbench:

An air flow bench is a device used for testing the internal aerodynamic qualities of an engine component and is related to the more familiar wind tunnel.

Valve geometry:

when this occurs, the angle formed by a line through the rocker shaft axis and the roller axis is at or very near 90 degrees to the valve stem when the valve is at the midpoint in its travel toward the full open position.

Procedure:

• First, design the flow bench and make it for flow simulation.
• Then go to flow simulation then save the file before running the simulation.
• Give a position for the valve and run the basic simulation by keeping the mesh size as 3 and produce the graphs.
• Then increase the mesh size as 4 and then 5 also take the velocity and pressure plots.
• After that select the best mesh size and make it to a parametric study.
• make the valve positions from 0.001 to 0.007 and get the mass flow rates.
• provide a graph and assign labels to it.

Model:

valve model:

Grid dependency test :

grid size as 3:

Velocity

Pressure:

grid size as 4:

Velocity

Pressure:

grid size as 5:

Velocity

Pressure:

According to the above three sizes the mesh grid size 5 is best for doing the parametric study so let us do the parametric study using mesh grid size 5.

Parametric study at mesh grid size 5:

we are assuming the conditions of the valve for about 7 positions the positions are 0.001,0.002,0.003,0.004,0.005,0.006,0.007

Open the parametric study in the simulation option then create each study by using a range step option, set the goal as mass flow rate in surface goals.

At 0.001:

Velocity:

Pressure:

At 0.002:

Velocity:

Pressure:

At 0.003:

Velocity:

Pressure:

At 0.004:

Velocity:

Pressure:

At 0.005:

Velocity:

Pressure:

At 0.006:

Velocity:

Pressure:

At 0.007:

Velocity:

Pressure:

Plot of mass flow rate:

Lift mass flow rate

0.001 0.07

0.002 0.1158

0.003 0.1578

0.004 0.1903

0.005 0.2207

0.006 0.2364

0.007 0.245

plot:

Result:

• From The pressure plot, we can observe that as the valve lift increase the pressure decreases due to the increase in distance between the valve opening and the cylinder.
• From the velocity plot, we can observe that as the valve lift increases the velocity increases, and the pressure decreases.
• Mass flow rate reduces as the valve lift increases this is because of the resistance to the flow due to the attachment to the valve seat and valve head.