Project : Steady state simulation of flow over a throttle body
STEADY STATE SIMULATION OF FLOW OVER A THROTTLE BODY
AIM:
To simulate the steady state flow over a throttle body using converge and analyse the results when the valve is at 0° position.
OBJECTIVES:
A control valve is a power operated device capable of modulating the flow at varying degrees between minimal flow and full capacity in response to a signal from the controlling system. Valves are available with a wide variety of valve bodies in various style, materials, connections and sizes. Here the simulation is performed by butterfly valve.
Butterfly valve consists of a disc attached to a shaft with bearing used to facilitate rotation. The flow capacity is relatively high and the pressure drop across the valve is relatively low.
In this case, the position of butterfly valve is at 0°, that is, it is parallel to the flow. When the flow enters at the inlet port it flows inside and passes across the valve without being blocked and reached out through the outlet port.
CASE SETUP:
Here, air is selected for the flow simulation. In the run parameters the solver is selected as steady state solver and the simulation mode will be in full hydrodynamic. In solver parameter, the Navier-Strokes solver type will be in pressure based.
In simulation time parameters:
End time: 15000 cycles
Initial time step: 1e-09sec
Min time step: 1e-09sec
Max time step: 1.0sec
In boundary condition:
Inlet (Boundary ID-4): Pressure- 150000Pa
Velocity- Zero Gradient
Temperature- 300K
Outlet (Boundary ID-3): Pressure- 100000Pa
Velocity- Zero Gradient
Temperature- 300K
Elbow wall: Wall motion type- Stationary
Surface movement- Fixed
Temperature- Zero Gradient
Throttle valve (0° position): Wall motion type- Stationary
Surface movement- Fixed
Temperature- Zero Gradient
In grid control:
Base grid: 0.002m
Fixed Embedding: Mode- Permanent
Scale- 3
Embed layers- 2
Pressure:
Pressure contours: https://www.youtube.com/watch?v=Z3N_2d4-vQM&feature=youtu.be
The Pressure ranges from 1.5bar to 1.0bar and as you can see, when the flow move towards the throttle, it divides the flow and then moves along the sides of the throttle which makes the pressure rise at that particular point. After that, the pressure decreases gradually when it moves towards the outlet.
Velocity:
Velocity contours: https://www.youtube.com/watch?v=qMml1KTTe4s&feature=youtu.be
The velocity is inversely proportional to the pressure. So, when the pressure increases at a point the velocity decreases and vice versa. Here you can see the max velocity of 200m/s occurs at the outlet port and min velocity of 2.6m/s occurs at the back side of the throttle.
Mass flow rate:
Total cell count:
CONCLUSION:
So, the steady state flow simulation process over the throttle body is done and the above result shows that, the steady flow has been achieved at around 5200 cycles.