Steady State Simulation of throttle valve

The throttle is a mechanism by which fluid flow can be regulated. It is widely used in Internal Combustion Engine to regulate the power and speed of the Engine. By means of the accelerator pedal, we control the opening of the throttle and thus control the fuel-air mixture.

In this simulation, a throttle valve is simulated for minimum opening condition and it is a steady-state simulation.

Geometry Details is shown below;

The Meshing has been done by

dx = 0.002 dy =0.002 and dz =0.002

The fixed embedding has been done at the throttle body for mesh refinement at the near throttle body.

The mesh refinement can be seen from the above fig near the throttle zone.

Boundary Conditions has defined as mentioned below;

Inlet Boundary Condition 150000.0 Pa Pressure

Outlet Boundary Condition 100000.0 Pa Pressure

Pin > Pout, So Flow will take place from inlet to out as favorable pressure gradient.

Elbow_Wall: Stationary wall and Law of Wall Boundary Condition applied

The roughness of the wall plays a significant role in turbulent flow for drag, heat and mass transfer calculation. If we model a turbulent wall-bounded flow in which the wall
roughness effects are considered to be significant, we can include the wall
roughness effects through the law-of-the-wall boundary condition.

Throttle: Stationary wall and Law of wall Boundary Condition applied.

Post Processing:

Velocity Contour at Inlet is shown below

We can observe from the above graph velocity before 4000 cycles are fluctuating while after 4000 cycles it remains constant. Since we are solving steady-state simulation so we can say before 4000 cycles simulation is not converged. Inlet velocity is approximately 180 m/s.

Pressure Inlet Contour

We can observe after 4000 cycles simulation is converged because the fluctuation in the Presuure is removed. Inlet Pressure at steady-state is approximately 121000 Pa.

Inlet Mass

We can observe after 4000 cycles simulation is converged because the fluctuation in the mass flow rate is removed. Inlet Mass flow rate at steady-state is approximately 0.066 kg/s.

Outlet Mass Flow Rate

We can observe after 4000 cycles simulation is converged because the fluctuation in the mass flow rate is removed. Outlet Mass flow rate at steady-state is approximately 0.066 kg/s.

We can observe from inlet and outlet mass flow rate is the same which satisfies the continuity equation i.e Inlet Mass Flow Rate = Outlet Mass Flow Rate

One more thing we can observe during the initial cycle (before 4000 cycles) inlet mass flow rate is decreasing while the outlet mass flow rate is increasing. Since the Inlet Pressure is higher than outlet pressure so the flow will develop from inlet to outlet. Therefore inlet mass is decreasing while the outlet mass flow rate is increasing. Same trend we can observe for velocity and Pressure also.

`v = (mass flow)/(\rho *A)`

Since Area at inlet and outlet is the same, so the trend of velocity will the same.

Velocity at outlet boundary

Pressure Outlet:

Total Cell Count

The total cell count is 41454. It is solved using parallel processing using 4 processors. All processor having approximately 10000 cells.

We can observe near throttle wall velocity is maximum while pressure is minimum, which satisfies the momentum equation.

We can also see the streamline