Week 4.2: Project - Transient simulation of flow over a throttle body

Assignment number 04

Assignment Name- Transient State Simulation of flow over throttle body using converge

Objective

1. Simulate flow over throttle body
2. Post process results and show Pressure contours and velocity contours
3. Show Mesh (Surface with edge)
4. Create the animation in which throttle movement should be visible

Steps

• Imported STL file in converge studio
• Setup the case
• Run the simulation in Cygwin
• Post process the results in PARAVIEW

Theory

Throttle:

A Throttle is a mechanism by which fluid flow is managed by constriction or obstruction.Engine power can be increased or decreased by the restriction of inlet gases. Term throttle has come to refer, informally to any mechanism by which the power or speed of an engine is regulated such as car accelerator pedal. Throttle is a device controlling the flow of fuel or power to an engine

Geometry

• Import STL files
• Cad cleans up means we don’t need thick pipe wall because it is nowhere useful to participate in the simulation. So, we will delete outer surface
• Then we used patch command for closing the open edges
• Then give boundary flagging
• Then check normal transformation, all the face normal direction should be facing towards the flow region
• And finally, diagnosis

Click on boundary and Create boundary

Checking normal

Before proceeding the error in geometry for that

View tab-diagnosis dock-default setting-select the find

Case Setup

Application Type = Time-based

Materials -

Predefined mixtures = Air

Simulation Parameters-

In Run Parameters two main things to be considered: -

select the following solver settings.

Simulation Time Parameters: -

Length of pipe=0.2m

Avg. velocity=200m/s

Velocity (Speed)= distance/time

200=0.2/time

We have run the cycles for minimum 10 times

Time=0.2/200

Time=0.001 sec

Hence, we run the simulation for 10 times

End time=0.001*10

End time= 0.01 sec

Pressure based transient state solver

Solver Parameters [Transient-State]-

Navier-Strokes Solver type- pressure based

Boundary condition

• Inlet-inflow-total pressure-150000 pa
• Outlet-outflow-total pressure-100000 pa
• Elbow wall-wall-no slip
• Setting up Throttle movement-wall

1. From 0 -2 ms valve rotate by 25 degrees
2. From 2 -4 ms valve it should stay at 25 degrees
3. After 8 ms valve should get back to its original position

inlet

outlet

Elbow wall

Throttle wall

• Setting up Throttle movement-wall

4. From 0 -2 ms valve rotate by 25 degrees
5. From 2 -4 ms valve it should stay at 25 degrees
6. After 8 ms valve should get back to its original position

Base grid

Fixed embedding

At throttle

Type-boundary, mode-permanent

Scale-3, embed layer-2

Note: check green tick mark on each option in case setup

Cygwin Window

Results

Mesh

Total of cells

Mass Flow rate

Inlet And Outlet

Pressure plot

Inlet and Outlet

Velocity plot

Inlet and Outlet

Pressure contour

Pressure contour at throttle

Velocity contour

Velocity contour at throttle

Stream trace:

Video link –

Pressure contour animation: -https://www.youtube.com/watch?v=Dzx6A8GsTwY

Velocity contour animation: -https://www.youtube.com/watch?v=UBU9BOUBsPg

Conclusions

• In these assignments we perform transient state simulation of flow over throttle body
• The total cell count is not constant because the throttle keeps changing the position, so the mesh changes with time
• Embedding is given because it ensured detailed physics near the wall