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

Title:Steady state simulation for flow over a throttle body

Objective: 1.Make case Setup for steady state

2. Observe the pressure, mass flow rate, velocity & total cell count

3. Post process the result in PARAVIEW

Theory: In this challenge bend pipe taken inside it throttle plate is present for vary the mass flow rate. in this case steady state solver taken. throttle plate is kept constant & observe pressure, mass flow rate, velocity & total cell count.

Case setup

1. Fluid used -Air

2. Solver- Steady state & Density based, Full Hydrodynamic

3. end time -15000cycle

4. Intial & minimum step =1e-9

5. Maximum time step= 1

6. Inlet pressure= 150000pa

7.outlet pressure=100000pa

7. Base Grid size = 2e-3 m

8. Fixed embedding : scale>3 & layer >2

9. Turbulence model: RNG K-E

Boundry ID & Name

Boundry ID

Mesh (Surface with edge)

Fixed embedding

for observe the pressure & velocity around a throttle plate there is need to refine the mesh. so, that there is use of fixed embedding.

Fixed embedding= (base grid size)/2^n

base grid size uses =0.002m

n=3= scale

Embed layer =2

fixed embedding= 0.002/2^3

= 0.00025 m cell size is present for 2 layer after that there is base mesh size is present.

Velocity contour

from velocity contour we can see that velocity is maximum at outlet & minimum at inlet, while on throttle plate lower velocity present. at the outlet higher velocity its because of air passing in smaller cross-section at throttle plate where velocity is zero but after the plate pressure is decrease & velocity is increases

Pressure contour

From below contour we can see that higher pressure at inlet & lower pressure at outlet, while on front side of throttle plate higher pressure & on back side is lower pressure. at the front side of throttle higher the pressure because it strike but on back side pressure is decreases because of sepration of boundry layer.

Pressure zone around Throttle plate

back side of the throttle plate lower pressure generated its due to the boundery separation, genration of recirculation zone.

at the front side of throttle higher the pressure because it strike but on back side pressure is decreases because of sepration of boundry layer.

lower pressure on back side of throttle plate

on backside of throotle plate lower pressure & lower velocity.

Velocity Animation

Velocity is minimum at the inlet because total pressure is higher but at throttle plate velocity is decrease becasue stagnation pressure. but after the throttle plate velocity is increases because decrease in total pressure

Pressure animation

at the inlet pressure is higher 1.5pa but at the front side higher pressure where stagnation point is present. but on back side of throttle lower the static pressure due to boundry separation layer & at outlet there is reduction of pressure

1. Mass flow rate

from the below plot we can verify that conitnuity equation which states that INFLOW=OUTFLOW mass flow rate

2. Aevrage velocity

from below plot we can see that inlet velocity is 100m/s but outlet velocity is higher its around 150m/s its because of reduction of total pressure at outlet

3. Static Pressure

from below plot we can see that inlet static pressure is higher , while outlet static pressure is constant 1pa

4. Total pressure

Total pressure =static pressure + Dynamic pressure . at outlet total pressure is decreases which means that velocity is increases on outlet its becasue of the when air passes from small cross-section area velocity increases & pressure reduction

5. Total cell

Total cell around 35000 its increases due to refine mesh around throttle plate

Overall conclusion

1. Fixed embedding helps for refine the mesh around the boundry of throttle plate, which helps for capture the correct velocity & preesure around throttle plate.

2. On front side of throttle plate higher pressure because air strike but on back side lower pressure generated due to the boundry sepration of layer , Static pressure is decreasses & velocity is zero.

3. Velocity is decrease on front side of the throttle plate but after that velocity increases because decrease in total pressure.