Week 4: Project - Transient simulation of flow over a throttle body

TRANSIENT FLOW OVER A THROTTLE BODY

Case setup:

Density based transient solver is used. In this case air is used which is compressible. There are four boundary condition in this case. Inlet wall is set as inflow boundary, outlet wall is set as outflow boundary, elbow wall is set as wall boundary(Law of wall),throttle body is set as wall type rotating boundary. Other specification are given below

1).Pressure at inlet is set to 101325pa

2).Pressure at outlet is set to 100000pa

3).Temperature is specified as 300k

4).Species concentration(oxygen 23%,nitrogen77%)

5).Start time is set to 0 second

6).End time is set to 12 millisecond(end time is approximated by dividing characteristic lengh with average velocity)

7).initial time step is 0

8).minimum time step is 1e-6

9).maximum time step is 1

11).SOR solver type is used and preconditioner is set to none

12).RNG K-epsilon turbulence modelling is used

13).Fixed embedding mesh with scale factor 2 is used at throttle wall

14).Base grid of mesh size 0.002mm is used

The plots and contours are given below

From the above figures and plot we can see that there is sudden variation of velocity and pressure ,this is because the flow get disturbed due to the rotation of throttle body.This causes the flow to change its velocity and pressure.