Simulation of Transient flow over a Throttle Body

Simulation Parameters

• Fluid = Air Mixture (23% Oxygen and 77% Nitrogen)
• Solver= Transient Solver
• Simulation time= 0.01 seconds
• Boundary Conditions

1. Inlet Pressure= 150000 Pa
2. Oulet Pressure= 100000 Pa
3. Top and Bottom Walls = No- Slip Walls
4. Front and Back Walls= 2-D

• Throttle Movement

1. At 0 ms = 0 degrees
2. At 2 ms = 25 degrees
3. At 4 ms = 25 degrees
4. At 8 ms = 0 degrees

Simulation Contours

• Mesh

• At 0 ms

• At 2ms

• At 4 ms

• At 8 ms

Converge uses a modified cut-cell Cartesian grid generation approach for the cells near the boundary surface, which allows for efficient calculations at the complex surfaces. The non-moving and non-deforming grid can easily accommodate cells around moving boundaries without a significant increase in computational expense.

1. From 0 to 2 ms, the number of cells increases as throttle moves from 0 to 25 degrees.
2. From 2ms to 4 ms, the number of cells almost remains same as throttle remains in the same position.
3. From 4ms to 8ms, there is decrease in the number of cells as throttle returns to its original position.
4. From 8ms to 10 ms, the number of cells remains cosntant.

• Velocity

• At 2 ms

• At 4ms

• At 8 ms

1. From 0 to 2 ms, the velocity increases as throttle moves from 0 to 25 degrees.
2. From 2ms to 4 ms, the velocity almost remains constant as throttle remains in the same position.
3. From 4ms to 8ms, there is parabolic increase in the velocity as throttle returns to its original position.
4. From 8ms to 10 ms, velocity reaches a constant value.

• Pressure

• At 2 ms

• At 4 ms

• At 8 ms

As Paraview only captures only static pressure, we have two plots. Inlet static pressure and total pressure at outlet because total pressure is defined at inlet and static pressure at outlet.

1. From 0 to 2 ms, inlet static pressure decreases and outlet total pressure increases.
2. From 2ms to 4 ms, the pressure almost remains constant as throttle remains in the same position.
3. From 4ms to 8ms, there is parabolic increase in the total outlet pressure and decrease in the static pressure as throttle returns to its original position.
4. From 8ms to 10 ms, pressure reaches a constant value.

• Mass Flow Rate

The mass flow rate follows the same profile as that of the velocity.

Animation

• Velocity

• Pressure