CFD ANALYSIS OF FLOW THROUGH A FLOW-BENCH USING SOLIDWORKS

AIM: Modelling & Simulation of Flow through a Flow-bench.

OBJECTIVE:

1) To create a 3D model of a flow bench and run flow analysis. Obtain plot of lift vs mass flow rate.

2) Perform Grid dependence test For three grids.

3) Run simulation at a particular valve lift and explain the results.

4) Effect of valve lift on mass flow rate for the decided best grid, run a parametric sweep to show the effect of valve lift on mass flow rate.

AIR FLOW-BENCH:

> 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 I. C. 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 flow bench consists of an air pump of some sort, a metering element, pressure and temperature measuring instruments such as manometer, and various controls. The test piece is attached in series with the pump and measuring element and air is pumped through the whole system. Therefore, all the air passing through the metering element also passes through the test piece. Because the volume flow rate through the metering element is known and the flow through the test piece is the same, it is also known. The mass flow rate can be calculated using the known pressure and temperature data to calculate air densities, and multiplying by the volume flow rate.

PROCEDURE:

1) Create the model using given dimensions.

2) Do the prescribed flow simulation study. with following input parameter's:

i) Flow medium = Air

ii) Boundary conditions: for inlet = Total pressure (101325 Pa)

for outlet = Static pressure (34027 Pa)

iii) Input surface goals = mass flow rate.

iv) Mesh = levels 3, 4 & 5

v) Results: Cut plot = velocity contour (front plane).

vi) Dimension feature added in analysis for different valve position on a range of 0.001 to 0.008m with total number of 7 spans.

GRID DEPENDENCY TEST:

> The results for the test are obtained as Velocity contour plots.

1) MESH GRID = 3:

2) MESH GRID = 4:

3) MESH GRID = 5:

> From the above results it is clear that as the level of the grid increases the refinement is result happens. For the new parametric study of valve potiocn variation is performed for the grid level of 4(according to system capabilities).

PARAMETRIC STUDY:

> The parametric study is performed for the valve lift position i the range of 0.001 to 0.008m with total number of 7 spans.

> The velocity contours according to every valve lift position are analysed from the following results.

1) VALVE LIFT = 0.001 m :

2) VALVE LIFT = 0.0002166 m :

3) VALVE LIFT = 0.00333 m :

4) VALVE LIFT = 0.0045 m :

5) VALVE LIFT = 0.0056 m :

6) VALVE LIFT = 0.00683 m :

7) VALVE LIFT = 0.0008 m :

> It is observed that the amount of mass of air entering the cylinder increases and air enters with higher velocity due to initial high pressure and valve opens the pressure gets reduced inside the inlet port.

MASS FLOW RATE RESULTS:

> RESULT DATA:

Goal (Value)	Design Point 1	Design Point 2	Design Point 3	Design Point 4	Design Point 5	Design Point 6	Design Point 7
D5@Sketch4@FLOW - BENCH.Part [m]	0.001	0.002166667	0.003333333	0.0045	0.005666667	0.006833333	0.008
SG Mass Flow Rate 1 [kg/s]	-0.027236942	-0.04316259	-0.054998937	-0.063604251	-0.069302984	-0.071833268	-0.072285977

> PLOT:

> The Mass flow rate is increases with the valve lift actually. But the data obtained from the simulation study in solidworks is done from the goal selection and according to that all values given by solidworks are negative. That negative values are positive in actual conditions.

> Therefore it is concluded that the mass flow rate increases with advancement in valve lift.