Flow Simulation Study | Modelling and simulation of flow through a FLOW-BENCH using SOLIDWORKS.
AIM:
To perform the flow bench simulation and to select the best mesh grid size and to run a parametric study on different valve lifts.
PROCEDURE:
- Create a flow bench model and apply lids on both inlet and outlet.
- Now create a new wizard for creating a simulation for study state condition and take the fluid like air.
- Give boundary conditions i.e. Total pressure of 101325 pa at the inlet port and static pressure of 34027pa at the outlet.
- Now we should choose the best mesh grid size and result in the accuracy of different mesh grid sizes.
TOTAL PRESSURE: Total pressure is the measure of the total energy of the airstream, and is equal to static pressure plus velocity pressure. The total pressure is the sum of the static and dynamic pressures. The total pressure is the total of static pressure p, dynamic pressure q, and gravitational head.
STATIC PRESSURE: The pressure of a fluid on a body when the latter is at rest relative to it.
DIMENSIONS OF FLOW BENCH:
- Diameter of cylinder = 0.1 m
- The diameter of inlet port = 0.025 m
- Length of cylinder(Extruded) = 0.1 m
Now let us do the grid dependency test
GRID DEPENDENCY TEST:
Considering the lift of the valve as 0.0003 m, let us run the test for a mesh grid size of 3,4,5.
TEST 1
Mesh Grid Refine Level 3
VELOCITY PLOT CONTOUR:
PRESSURE PLOT CONTOUR:
The above is the output results of mesh level 3 at 64 number of iterations. we can notice the change of velocity at different places of the flow bench.
TEST 2:
Mesh Grid Refine level 4
VELOCITY PLOT CONTOUR:
PRESSURE PLOT CONTOUR:
we can notice as mesh level is refined the results are quite good as compared to the above Test 1, and the number of iteration in this test also increased.
TEST 3
Mesh Grid Refine Level 5
VELOCITY PLOT CONTOUR:
PRESSURE PLOT CONTOUR:
As we know that the results are more accurate as of the refine level increases. So, I go with mesh grid size 5 as it provides me the best results, and the number of iteration also increased.
Now let us perform a parametric study of valve lift. Below is the result of the above parametric study.
PARAMETRIC STUDY:
Now let us consider different lift of value of the range of 0.0001 m to 0.0008 m and let us run the study.
In the parametric study give the input variables as valve lift dimension parameter and output parameter as surface goals of valve surface and front plane cut plot.
STUDY 1
VALVE LIFT 0.0001 m
VELOCITY PLOT:
PRESSURE PLOT:
At this stage, the valve starts opening so the pressure is high at the inlet port and velocity at the edges of the valve is minimum here as it is zero at the inlet port
STUDY 2
VALVE LIFT OF 0.0002166 m
VELOCITY PLOT:
PRESSURE PLOT:
As valve lift increases you can note that air starts entering the cylinder thus velocity increases at inlet port and pressure decreases.
STUDY 3:
VALVE AT LIFT OF 0.00333 m
VELOCITY PLOT:
PRESSURE PLOT:
you can notice that due to change in the area the air enters cylinder port at higher velocity and pressure on inlet port decreases.
STUDY 4
VALVE LIFT OF 0.0045 m
VELOCITY PLOT:
PRESSURE PLOT:
The air gushes into the cylinder with high velocity and pressure on inlet port decreases but will be high at mid-point of the valve.
STUDY 5
VALVE LIFT OF 0.0056m
VELOCITY PLOT:
PRESSURE PLOT:
As the lift increases the velocity of the air entering the cylinder decreases and thus pressure on the wall decrease.
STUDY 6:
VALVE LIFT OF 0.00683m
VELOCITY PLOT:
PRESSURE PLOT:
We can notice that pressure reduces and you can note change velocity and pressure contours inside the cylinder, which means air is entering the cylinder, and velocity further increases.
STUDY 7:
VALVE LIFT OF 0.0008 m
VELOCITY PLOT:
PRESSURE PLOT:
we can note 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.
OUTPUT RESULTS:
Graph of different design points are as below:
Actually, the mass flow rate increases but as the goals are specified on valve surface only the results are negative
FLOW TRAJECTORY:
we can create a flow trajectory of flow air for a valve lift of 3mm by specifying the origin face and number of nodes in the flow trajectory option.
Velocity trajectory:
Pressure Trajectory:
RESULT:
From the above study, we can say that parameters such as pressure, velocity, and mass flow rate are critical for designing of flow bench, as the higher velocity rate improves the combustion of the fuel and can produce higher power. This is a simulation of what happens in the suction stroke of an engine. The parameters are important such that it helps in reducing the effect of knocking in the engine. As stated above the change in pressure and area helps to increase velocity. For more power turbocharger can also be added.