Week 9 - Parametric study on Gate valve.
GATE VALVE PARAMETRIC STUDY
AIM:
To perform a parametric study on the gate valve simulation by setting the opening from 10% to 80%
OBJECTIVE:
To set the gate disc lift distance as input parameter and mass flow rate as output.
To calculate the flow coefficient and flow factor for each opening of gate disc lift from 10-80%
INTRODUCTION:
Gate valve are the valve used to start or stop fluid flow.
Gate valve are the valve which opens by lifting the barrier out of the path of fluid flow.It requires little space along the pipe axis and it controls the fluid flow when the gate is opened.
Gate valve consists of hand wheel and spindle connected to gate disk.
THEORY:
Parametric study is about the mass flow rate at outlet of gate valve during different levels of lift of gate disk.
METHODOLOGY FOR PARAMETRIC STUDY OF GATE VALVE :
Create an output parameter for opening the gate valve from 10% to 80%.
Adapt fluid volume to changing solid geometry.
GEOMETRY:
Select the Gate disc component and lift upto 10mm the gate valve and parameterize it.
Extract the 3 edges of model and pull the pipe's outer solid surface i.e., the inlet and outlet upto 800mm.
YZ plane is created along the model and update the volume body in context.
Suppress all the parts except volume
MESH:
Name the inlet and outlet.
Element size :5.5mm
Generate the mesh and update it.
Cell count : 484644
SETUP:
As Z acts on the upward direction, g= -9.81m/s
Pressure based solver as we solve pressure,mass flow rate
Steady state.i.e., independent of time.
Create fluid material as water liquid(flow of water) instead of air.
Boundary condition :
Inlet pressure is about 10pascal.
Realizable k-epsilon model and scalable wall function.( for the pipe flow, Reynolds number 2000 is turbulent)
Standard initialisation is done as inlet pressure is known.
Create flux report for mass flow rate and output as parameter.
Number of iteration = 500
When calculation is completed,add one more parameter,update and retain that parameter.
After getting valid mass flow rate output with respect to lift valve,add 20,30,40,50,60 parameter and retained those parameters.
Select all parameters as needed and update all selected.
SOLUTION:
RESIDUALS :
10%
20%
30%
40%
50%
60%
MASS FLOW RATE PLOT :
10%
20%
30%
40%
50%
60%
| GATE VALVE OPENING % | MASS FLOW RATE in kg/s |
| 10 | 0.12901 |
| 20 | 0.22809 |
| 30 | 0.34228 |
| 40 | 0.46254 |
| 50 | 0.56678 |
| 60 | 0.64964 |
POST PROCESSING :
VELOCITY CONTOUR :
10%
20%
30%
40%
50%
60%
PRESSURE CONTOUR :
10%
20%
30%
40%
50%
60%
PARAMETRIC STUDY TABLE OF GATE VALVE :
FLOW COEFFICIENT:
When sizing a control valve,the most common approach is to calculate the flow coefficient.
Flow coeffiecient determines the valve size that allow valve to pass the required flow rate while providing stable control of process fluid.
Its the relative measure of its efficiency at allowing fluid flow.It describes the relationship between pressure drop across an orifice valve or other assembly or corresponding flow rate.
`C_v = Q sqrt ( (SG)/(triangleP))`
C_v = Flow coefficient
Q = Rate of flow(USgallon per minute).
SG = Specific gravity of the fluid
`triangle P`= Pressure drop across the valve (psi)
FLOW FACTOR :
`K_v = 0.865 C_v`
CALCULATION :
For 30% of opening gate valve
`Q = 0.34228 (kg)/s`
`(kg)/s`into `(gal)/min`
`1 (kg)/s = 15.85(gal)/min`
`Q= 0.34228*15.85=5.43(gal)/min`
pascal into psi ;
1pascal = 0.0001450377 psi
Flow coefficient:
`C_v = Q sqrt ( (SG)/(triangleP))`
`C_v=5.43*sqrt(1/0.0014503)`
`C_v=142.584 gal (min)^-1 * psi^-0.5`
Flow factor :
`K_v = 0.865 C_v`
`K_v=123.335`gal (min)^-1 * psi^-0.5``
| GATE VALVE OPENING % | MASS FLOW RATE in kg/s | MASS FLOW RATE in gpm | Flow coefficient in `gal (min)^-1 * psi^-0.5` | Flow factor in `gal (min)^-1 * psi^-0.5` |
| 10 | 0.12901 | 2.04 | 54.8802 | 47.4714 |
| 20 | 0.22809 | 3.62 | 95.0577 | 82.22 |
| 30 | 0.34228 | 5.43 | 142.584 | 123.335 |
| 40 | 0.46254 | 7.33 | 192.47 | 166.486 |
| 50 | 0.56678 | 8.98 | 235.8013 | 203.968 |
| 60 | 0.64964 | 10.30 | 270.4625 | 233.95 |
CONCLUSION :
When we increase the opening percentage of the gate valve,mass flow rate and velocity increases.
Flow coefficient and flow factor also increases with respect to opening percentage of gate valve.
Gate valve should be operate in 100% closed or open while partially opened flow procces induce vibration which may damage gate valve