Modelling and Simulation of Flow through a Flowbench

Aim: Creating a 3D model of FlowBench in SOLIDWORKS and performing flow simulation.

Objective: Performoing Parametric Study on

1. Performing Grid Dependent test
2. Effect of mass flow rate on valve lift

Theory:

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.

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.

Creating a 3D Model

Below figures shows the complete views of a designed Flow bench along with its detailed view.

Creating Baseline Simulation

1. Before starting the flow simulation, the geometry was closed by creating lids as the analysis type to be used was internal flow.
2. Then wizard tool was selected and following inputs were set.

Applying Boundary Conditions

Adding Local Mesh and Surface Goals

Solving the Model and post processing the results

Pressure and Velocity Plots

1. As the valve is no completely opened, there is a pressure difference generated of about 96 Pascals
2. The inclined geometry of the pipe maintained the maximum velocity as the right-hand side of the valve.
3. Due to increase in velocity at the right-hand side of the valve there is a swirl generating at that area which could be seen through the streamlines shown in the second figure.

Animation Videos

Parametric Study 1: Grid Dependent Test

Following were the conditions set while performing parametric Study

	Design Point 1	Design Point 2	Design Point 3	Design Point 4
Level of initial mesh (Automatic Mesh) [ ]	3	4	5	6

Pressure, Velocity and mass flow rates were calculated for these four conditions which are explained as follows:

Pressure Plots

Velocity Plots

Goal Plots (Mass Flow Rate )

Goal (Value)	Design Point 1	Design Point 2	Design Point 3	Design Point 4
Level of initial mesh (Automatic Mesh) [ ]	3	4	5	6
SG Mass Flow Rate 1 [kg/s]	-0.23259253	-0.232069957	-0.232589295	-0.230641792

As there are refinement of mesh, there is slight changes in the Outlet mass flow rates values.

Thus keeping computational time and device constraints, Level of initial mesh was set to 5 for calculation of below parametric study.

Parametric Study 1: Valve Lift v/s Outlet mass flow rate

Following were the conditions set while performing parametric Study

	Design Point 1	Design Point 2	Design Point 3	Design Point 4	Design Point 5	Design Point 6	Design Point 7	Design Point 8	Design Point 9	Design Point 10
D6@Sketch12@Cylinder Head.Part [m]	0.00343	0.004541111	0.005652222	0.006763333	0.007874444	0.008985556	0.010096667	0.011207778	0.012318889	0.01343

mass flow rates were calculated for these conditions which are explained as follows:

1. From the graph, it is clear that as the valve opens, mass flow rate goes on increasing and finally it becomes constant.
2. Note the negative values of mass flow rates just gives the direction of the velocity, it has nothing to do with the magnitude.

The velocity variation are shown below

Pressure Variation

Conclusion

1. As the valve lift increases, mass flow rate increases.
2. Due to inclined pipe geometry, there are non-uniform swirls that can provide good turbulence in mixing of fuel in case of diesel engines.
3. Pressure Difference and valve lift causes increase in the velocity through inlet.
4. Improper valve design may result in sonic velocities inside the chamber.