Week 4.1: Project - Steady state simulation of flow over a throttle body

Aim

To perform the Steady 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

Creating boundary fence using Boundary>Find/clean as follows

As the geometry has some thickness to it, and we are not interested in heat transfer so we will delete the thickness of the elbow using Traingles by angle selection as follows

Now after deletion

Now if we run the diagnosis we get the open edges error as there are in with yellow edge colour

Using Repair>Patch with open edge selection we select and fill the openings

Click on boundary and Create boundary

 

Checking normal

 

 Diagnosis dock

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

 

Case Setup

Gas Simulation

Global transport Parameters

Species

 

Simulation Parameters

In Run Parameters two main things to be considered: -

select the following solver settings.

 

Steady-State Monitor

Simulation Time Parameters: -

Pressure based steady state solver

Start time-0

End time-15000 cycle

Initial time step-1e-09s

Minimum time step-1e-09s

Maximum time step-1s

Simulation

Solver Parameters [Steady-State]

Navier-Strokes Solver type- pressure based

 

Boundary condition

Inlet-inflow-total pressure-150000 pa

Outlet-outflow-total pressure-100000 pa

Elbow wall-wall

Throttle-wall

inlet

 

outlet

 

 Elbow wall

 

Throttle wall

 

Region

Physical model

Turbulence Model

Base grid

 

Fixed embedding

At throttle

Type-boundary, mode-permanent

Scale-3, embed layer-2

 

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:

 

Conclusions

• In these assignments we perform steady state simulation of flow over throttle body
• We observe the red zone near the throttle wall it is because of high pressure air coming from inlet
• Embedding is given because it ensured detailed physics near the wall