Channel flow simulation using CONVERGE CFD

Title: Channel flow simulation using CONVERGE CFD

Objective: 1. Make setup for flow through channel

                  2. To run the simulation for three diffrent mesh size 2e-4, 1.5e-4, 1.2e-4

                  3. Plot the velocity, pressure, mass flow rate, total cell count

Theory

             Consider the air is passing in to the channel & fluid flow is laminar. its very important to obey the continuity equation. i.e INFLOW should be equall to OUTFLOW. also its very important to verify the velocity profile should be in parabolic nature. 

Steps for simulation & setup

1. Geometry creation 

geometery is created in to the CONVERGE STUDIO by distance of given image

2. Boundry name

its very important to give the boundry name for given geometry . so, there is given name like Inlet, outlet, top& bottom walls etc.

3. Enable normal vectors

Its need to check the nomral vector should be pointing towords flow not to the outside of flow . so, in transform we can do that.

4. Appication type 

Consider the Time-based

5. Materials

1. Predifined mixture should be Air 

2. Material gas id N2 & O2

6. Simulation time parameters

run the simulation for 15000cycle , intial & minimum time step is 1e-9. maximum is 1

6.1 Steady state parameters

monitor variable is consider the Aveg velcoity & total pressure. based upon this variable solution will converge. 

6.3 Solver parameter

Navier stroke solver is PISO & Scheme is Density based

consider the maximum CFL NO. is 0.5

7.Boundry Condition

for respective boundry select the boundry type

1       Inlet > Boundry type> INFLOW               

         Pressure >100001pa         Inflow> Air   Temp >300k

2.    outlet > Boundry type> OUTFLOW               

         Pressure >100000pa         outflow> Air          Temp >300k

3. Top & bottom>Boundry type>walls   & NO-SLIP condition

4. FRONT & BACK>Boundry type>TWO_D  

8. Region selection

1. For each every boundry its necessary to give the specfied region & in that region consider the Air is flow. 

2.maintain the inlet & initial pressure same

9.Base grid Size

Grid size consider for dx, dy dz direction

 1) 2e-4                             2) 1.5e-4                   3)1.2e-4    

10. Output/ Post-process

Species defined N2 & O2

10.1 Output files

 for every 100 cycle generation of output file

1. Velocity & Pressure contour

Sample velocity contour for 1.2e-4 mesh size

2. Mesh (surfaces with edge)

CASE1: 2e-4

CASE2: 1.5e-4

case 3: 1.2 e-4

Various Plots

1. Mass flow Rate plot 

mass flow rate plot can shows that INFLOW=OUTFLOW its proove that continuity equation. its observed that for higher grid size higher the mass flow rate , while lower gride size lower  the mass flow rate

1. Aevrage velocity  

Aevrage velocity plot can shows that INFLOW=OUTFLOW velocity , its proove that continuity equation. its observed that for higher grid size higher theVelocity  , while lower gride size lower  the velocity

Total Preesure

from below plot we can observe that inlet pressure is 1 pa above 1 bar for outlet total preesure is try to achieve with inlet pressure there is very smaal difrrrence in pressure . for lower mesh grid size higher the pressure drop.

Total Cell count for Diffrent Mesh 

for 2e-4 =25000 cell,   1.5e-4 =46000 cell    1.2e-4= 70000cell

its observed that lower the mesh size higher the total cell & simulation time is also higher

Velocity Magnitude Profile in PARAVIEW

CASE1: 2e-4

Proove that Velocity is maximum at centre of channel & zero at wall surface 

CASE2: 1.5e-4

Proove that Velocity is maximum at centre of channel & zero at wall surface 

case 3: 1.2 e-4

Proove that Velocity is maximum at centre of channel & zero at wall surface & give smooth parabolic curve due to mesh size is very small

Overall conclusion 

1. As the grid size increase the total cell count increase & also increases simulaton time

2. As the grid size increase the result are more accurate & curve are smooth

3. Proove that continuity equation INFLOW=OUTFLOW for all parameter mass flow rate , Aevrage velocity &Total Pressure 

4.  Proove that Velocity is maximum at centre of channel & zero at wall surface