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

Aim - Steady-state simulation of flow over a throttle body in Converge 3.0

Introduction - Observing the flow over a throttle body at a stationary position.

Theory -

Geometry -

• Geometry creation-
  • Geometry was Imported. Drag-Drop
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• Boundary Flagging
  • Boundaries were defined using the Boundary function
  • 4 different boundaries were defined as follows -
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Case Setup

• Application type > Time-based
• Materials> Select Predefined mixture "Air"
  • O2 and N2 Gas species added
• Simulation parameters
  • Run Parameters - Select steady-state monitor> Add variables that are needed to be monitored(Velocity, Pressure, mass flow rate, etc)
  • Simulation time parameters-End time 15000 cycles
  • Solver parameters(SS)-Density-based NS solver
• Boundary conditions-parameters assigned as follows
  • Inlet-Inflow Type-150000Pa. 300K, Air Species
  • Outlet-Outflow Type-100000Pa. 300K. Air Species
  • Elbow wall - Wall - Law of wall - Fixed movement
  • Throttle - Wall - Law of wall - Fixed movement
• Initial Conditions and Events
  • Region and initialization Add Volumetric Region with Air species. Initial pressure-Inlet pressure-101325.0Pa. 300K.
• Physical Models - Turbulence Model - RNG-k-e
• Grid Control
  • Base Grid - 0.002x0.002x0.002 m
  • Fixed Embedding
    • Boundary-Top and Bottom- Permanent-Scale-2. Embed Layers 2
• Output/Post-processing
  • Time interval 3D O/p files - 1000cycs
• Advanced Parameters
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Observations - After running the calculation on Cygwin following are the results observed in Paraview and Converge Line plotting tool. The calculations were done with Fixed Throttle as mentioned below. At the start, we observed the pressure difference between Inlet and Outlet leading to a unidirectional flow through the channel. Flow over the throttle clearly visible in the below cases when the throttle is stationary.

• Mesh -
  • Mesh and Cell count -
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• Pressure across the Elbow and Throttle
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• Velocity across the Elbow
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• Mass Flow rate across the Elbow
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• Conclusion -

  The flow over the stationary throttle is observed and pressure on the throttle body close to the inlet is high.

  In the velocity and pressure plots, we observed that Pressure and velocity are inversely proportional to each other

  Flow can be observed from the High-pressure inlet to the Low-pressure outlet.

  The mass flow rate plot indicates that mass flow through the inlet equals mass flow through the outlet. No accumulation mass inside the channel.