FLOW ANALYSIS THROUGH A FLOW-BENCH (using SOLIDWORKS)

AIM:

To design and simulate the flow through a flowbench using SOLIDWORKS

OBJECTIVE:

1. To simulate a Grid Dependence test, i.e. to perform a simulation for different mesh grids for getting an exact flow geometry
2. To run a parametric study to show the effect of valve lift on mass flow rate of the flowbench
3. To understand the workings and flow trajectory through the flowbench

INTRODUCTION:

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 IC 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.

A simple flowbench can be seen below:

The valve inside the flowbench regulates the amount of air that can flow through it after entering through the inlet.

PROCEDURE OF COMPLETION:

1. First, a flowbench was setup alongwith the valve inside it.
2. Then, a computational domain was setup for the flow simulation to take place.
3. Then, boundary conditions i.e. (Total pressure at the inlet and Static pressure at the outlet) was provided. Here, total pressure is taken as `1` bar and static as `0.5` bar.
4. Then, mass flow rate was given as a goal to be computed alongwith the velocity and pressure.
5. Then, different sizes of grid were tested (with mesh refinement of `5`,`6`,`7` ) for getting an accurate flow simulation.
6. Then, a parametric study was setup using the dimension of the valve for allowing a desired amount of fluid (here, air) to enter.

OBSERVATIONS:

• Grid Dependance Test:

For meshgrid = `5`, the velocity of the flow is as follows:

For meshgrid = `6`, the velocity of the flow is as follows:

For meshgrid = `7`, the velocity of the flow is as follows:

Hence, it can be clearly observed that with more the size of the meshgrid, more the refinement of the flow simulation was achieved. Hence, a meshgrid of `7` was used for further computation.

• Mass flow rate vs Valve-Lift and Flow Trajectory:

For valve-lift of `1mm` to `10mm` , a parametric study was computed using the meshgrid of `7`.

Parametric study:

For valve-lift of `1mm`,

The velocity of air is as follows:

The flow trajectory is as follows:

For valve-lift of `2mm`,

The velocity of air is as follows:

The flow trajectory is as follows:

For valve-lift of `3mm`,

The velocity of air is as follows:

The flow trajectory is as follows:

For valve-lift of `4mm`,

The velocity of air is as follows:

The flow trajectory is as follows:

For valve-lift of `5mm`,

The velocity of air is as follows:

The flow trajectory is as follows:

For valve-lift of `6mm`,

The velocity of air is as follows:

The flow trajectory is as follows:

For valve-lift of `7mm`,

The velocity of air is as follows:

The flow trajectory is as follows:

For valve-lift of `8mm`,

The velocity of air is as follows:

The flow trajectory is as follows:

For valve-lift of `9mm`,

The velocity of air is as follows:

The flow trajectory is as follows:

For valve-lift of `10mm`,

The velocity of air is as follows:

The flow trajectory is as follows:

Now, computing the mass flow rate from the outlet for different valve-lifts,

CONCLUSION:

1. From the Grid Dependence test, it is concluded that higher the size of the meshgrid, more refined is the flow simulation and analysis and more accurate would be the results.
2. From the velocity analysis and flow trajectories, it can be concluded that more the valve-lift, more is the velocity of the fluid coming through the inlet which is trivial.
3. The time taken to settle down inside the tank also increases with increase in valve-lift as the velocity of the fluid tends to be more in higher valve-lifts which takes time to settle down.
4. The mass flow rate is negative as mass is being ejected by the system through the outlet.
5. More is the valve-lift, higher is the ejection of the mass through the outlet and more negative it becomes.
6. The mass flow rate increases with a decreasing slope, i.e., after a certain valve-lift, the mass flow rate won't change.