Week 4.1: Project - Steady state simulation of flow over a throttle body
Project - Steady-state simulation of flow over a throttle body
AIM:-
To set up and run the steady-state simulation of flow over a throttle body and find the pressure, velocity and mass flow over through the body by using the Converge 3.0 software.
INTRODUCTION: -
When designing a new fuel management system for a IC engine the amount of air that is fed to the cylinders is highly important. A tool that is being used to improve the performance levels of engine modeling where a fuel management system can be tested and designed in a computer environment thus saving valuable setup time in an engine test cell. One important part of the modeling is the throttle which regulates the air by using the converge software 3.0.
PROCEDURE: -
Step 1: Creating the 3D model of the throttle body elbow pipe using the modeling software in the format of .stl file.
Figure 1: Steady-state flow over the throttle body
Step 2: Using the converge studio index open the .stl elbow pipe and add a single boundary.
Step 3: The wall thickness of the pipe should be neglected for this steady-state simulation process. To eliminate the thickness by using the geometry commands.
Step 4: Using the boundary command-click find separate the fence and select the boundary area and click the delete option.
Step 5: Next click the arc command select by angle delete the circular object. Then by using the diagnosis command find the open edges.
Step 6: Click the repair and patch option then select the open edges to click apply all the open edges are closed. Must verify the command by using the diagnosis command.
Step 7: Select the boundary command-click to add boundary 5 more boundaries are added.
Select the inlet and outlet boundaries are 1 and 2 respectively.
Step 8: Select the total elbow wall in boundary 4 named as elbow wall.
Step 9: Next to select the throttle valve, hide the elbow wall by using the box pick option, select the by surface method total throttle valve is selected as the boundary 3 from the body.
Step 10: After the separation of all boundaries click the setup option and click the Application type and select the time-based option, here the problem was a steady-state condition, it’s not an IC engine problem it depends on the time only.
Step 11: Next to select the materials, the predefined mixture was air and select the option as gas simulation, add the species option and select ok.
Step 12: Next for the global transportation parameters as the default option is selected and the species option-click and add the O2 and N2 are the airflow inlet gases.
Step 13: Next for the simulation parameters click the solver as a steady-state solver, it’s the necessary condition for this case. For the miscellaneous option select the steady-state monitor option.
Step 14: Next click the steady-state monitor option add the various variables as Average temperature, Total pressure, average velocity and select the target type is boundary also select the target is an outlet for the condition.
Step 15: Next for the important step, simulation time parameters set the start time is 0.0 Cycle, End time is 15000 cycles, Initial time step is 1e-7, Minimum time step is 1e-7 and the maximum time step is 1 second.
Step 16: Next for the solver parameters Navier – stokes solver type is pressure-based and pressure precondition is none and steady-state solver Initial PISO convergence criterion multiplier value is just below 1 set the value is 0.5.
Step 17: Next to select the boundary conditions for the flow as first for the inlet flow pressure is set to be 1.5e5 Pa and airflow also added.
Step 18: For the outlet select the pressure as 1e5 Pa and also added the air in the outlet flow. The elbow wall is selected as a wall boundary and it's selected as a no-slip wall.
Step 19: Finally, the total surface of the throttle also selected as the wall and the wall is set to be a no-slip wall.
Step 20: For the base grid selection the grid value is set to be 0.002m for all the directions.
Step 21: In this grid selection also added an embedding selection, it’s very useful to separate the elements in the complicated shapes in an ahead manner. The fixed embedding creates the minimum size of the elements creations.
Figure 2. Fixed Embedding of the throttle wall
Step 22: Next for the post variable selection select the two species in the field of mass fraction and select ok.
Step 23: The time interval for the 3D output data files is 1000 Cycles and the Time interval for writing restarting output is 1000 cycles are should be selected in the field of post processing selection.
Step 24: Finally export all the data into the selected folder and also copy the mpiexec and converge-intelmpi files into the folder and run the program.
Step 25: Also post-processing is done using the converge 3.0 simulation process .vtm group file also created.
RESULTS: -
Pressure and velocity contours for the steady-state flow in the throttle body
Figure 3: Initial pressure flow of the throttle body without embedding process
Figure 4: Final pressure flow of the throttle body without embedding process
Figure 5: Initial pressure-flow contour of the throttle body with the embedding process
Figure 6: Final pressure-flow contour of the throttle body with the embedding process
Figure 7: Initial velocity contour of the throttle body with embedding process
Figure 8: Final velocity contour of the throttle body with the embedding process
Figure 9: Initial temperature contour of the throttle body with embedding process
Figure 10: Final temperature contour of the throttle body with embedding process
Figure 11: Mesh position of the throttle body surface with edges
Figure 12: Inlet, outlet and throttle boundaries are visible and color differentiation in a single 3D view
Figure 13: Final velocity direction contour of the throttle body
Figure 14: Surface with the edge position contour of the throttle body pressure flow
Figure 15: Surface contour of the throttle body pressure flow
Figure 16: Steam tracer of the steady-state flow through the throttle body
Mass flow rate contour graph for the steady-state flow through the throttle body
Figure 17: Inlet mass flow rate of the steady-state flow through the throttle body
Figure 18: Outlet mass flow rate of the steady-state flow through the throttle body
Figure 19: Total cell count of the steady-state flow problem
EXPLANATION: -
In the steady state flow of the throttle body problem, the air is taken into the elbow pipe and fixed throttle valve is fixed in the center of the elbow pipe. In the fixed boundary valve the air passing through the pipe in the flow of laminar flow. The pressure deviation is maintained in the inlet and outlet boundaries. The elbow wall is selected as the simple two dimensional wall, so the thickness of the wall does not affect the flow through the pipe. So, the thickness of the pipe is neglected in the steady state flow of the pipe.
The embedding process gives the most precision in the element creation, the irregular shapes also creating the minimum size of the element in the embedding process. The fixed embedding is used in the steady state problem and also permanent boundary selection very helpful to improving the shape of the throttle body.
The velocity increases at the throttle valve edges and the velocity of airflow through the clearance between the valve edge and the pressure decreases in the intermediate cylinder.
CONCLUSION: -
The pressure and velocity variation over the throttle body were analyzed. The study of different regions formed showed that the throttle body and the velocity, temperature and pressure contour plots are analyzed using Converge 3.0 software.
Link for the YouTube Video: - https://youtu.be/sQdA2woVYvM