Gate Valve Parametric Study
INTRODUCTION
Gate Valve is used to control the mass flow rate in a pipe. For different lifts of the valve, there will be a different mass flow rate at the outlet. To obtain the mass flow rate at different lifts a CFD simulation can be performed. The geometry used for the simulation is shown below:
The simulation for the different lift can be performed by a parametric study in Ansys Workbench. The parametric study is performed by parametrizing the lift height in SpaceClaim. Firstly the fluid volume should be extracted by selecting inlet and outlet edges. In this report, the parametric study is done for 6 design points (i.e., lifts) to obtain mass flow rate.
NUMERICAL MODEL
Design Point 1: 0 mm Lift
Geometry:
The below figure shows the cut view section of the gate valve indicating 0 mm lift.
Mesh:
The below figure shows the cut section mesh of the gate valve and all the elements are of element type tetrahedral.
The below image shows the mesh quality. The quality is good and we can proceed for performing simulations. The mesh parameters are shown in below table:
|
Element Type |
Tetrahedral |
|
Element size |
9 mm |
|
Cell Count |
220062 |
Setup:
Water is used as the fluid and properties of water used for simulations are shown in below table:
Density - 998.2 kg/m3
Viscosity - 0.001003 kg/m-s
The equations solved are the RANS (continuity and momentum) equations. The turbulence model used in the simulations is realizable two-equation k − ε turbulence model with scalable wall functions. The computations are performed using ANSYS FLUENT with steady, double precision and a pressure-based solver is used. The SIMPLE algorithm is selected for the velocity-pressure coupling. The second-order upwind scheme is used for the space discretization for higher accuracy. The boundary conditions for the model are shown in below table:
|
Boundary |
Condition |
|
Inlet |
Gauge Total Pressure= 10 Pa Turbulent Intensity = 5% Turbulent Viscosity ratio = 10 |
|
Wall |
no-slip condition |
|
Outlet |
Gage pressure = 0 Turbulent Intensity = 5% Turbulent Viscosity ratio = 10 |
The operating pressure used for the simulations is 1 atm or 101325 Pa.
Result:
The below figure shows the residuals and residuals looks good as there are no abnormal fluctuations. It took 562 iterations for convergence.
The below figure shows the pressure contour on the cut plane and the result satisfies the pressure boundary condition.
The below figure shows the velocity contour on the cut plane.
The below figure shows the velocity streamlines on the cut plane and we can see the formation of two vortices.
The below figure shows the variation of mass flow rate with iterations and the value of the mass flow rate is 0.10181 kg/s
Design Point 2: 5 mm Lift
Geometry:
The below figure shows the cut view section of the gate valve indicating 5 mm lift.
Mesh:
The below figure shows the cut section mesh of the gate valve and all the elements are of element type tetrahedral.
The below image shows the mesh quality. The quality is good and we can proceed for performing simulations. The mesh parameters are shown in below table:
|
Element Type |
Tetrahedral |
|
Element size |
9 mm |
|
Cell Count |
220593 |
Setup:
same as that in design point 1.
Results:
The below figure shows the residuals and residuals looks good as there are no abnormal fluctuations. It took 334 iterations for convergence.
The below figure shows the pressure contour on the cut plane and the result satisfies the pressure boundary condition.
The below figure shows the velocity contour on the cut plane.
The below figure shows the velocity streamlines on the cut plane.
The below figure shows the variation of mass flow rate with iterations and the value of the mass flow rate is 0.12277 kg/s.
Design Point 3: 10 mm Lift
Geometry:
The below figure shows the cut view section of the gate valve indicating 10 mm lift.
Mesh:
The below figure shows the cut section mesh of the gate valve and all the elements are of element type tetrahedral.
The below image shows the mesh quality. The quality is good and we can proceed for performing simulations. The mesh parameters are shown in below table:
|
Element Type |
Tetrahedral |
|
Element size |
9 mm |
|
Cell Count |
220038 |
Setup:
same as that in design point 1.
Results:
The below figure shows the residuals and residuals looks good as there are no abnormal fluctuations. It took 268 iterations for convergence.
The below figure shows the pressure contour on the cut plane and the result satisfies the pressure boundary condition.
The below figure shows the velocity contour on the cut plane and highest velocity is observed at the bottom of the valve having a narrow opening.
The below figure shows the velocity streamlines on the cut plane.
The below figure shows the variation of mass flow rate with iterations and the value of the mass flow rate is 0.14862 kg/s.
Design Point 4: 15 mm Lift
Geometry:
The below figure shows the cut view section of the gate valve indicating 15 mm lift.
Mesh:
The below figure shows the cut section mesh of the gate valve and all the elements are of element type tetrahedral.
The below image shows the mesh quality. The quality is good and we can proceed for performing simulations. The mesh parameters are shown in below table:
|
Element Type |
Tetrahedral |
|
Element size |
9 mm |
|
Cell Count |
219906 |
Setup:
same as that in design point 1.
Results:
The below figure shows the residuals and residuals looks good as there are no abnormal fluctuations. It took 399 iterations for convergence.
The below figure shows the pressure contour on the cut plane and the result satisfies the pressure boundary condition.
The below figure shows the velocity contour on the cut plane.
The below figure shows the velocity streamlines on the cut plane.
The below figure shows the variation of mass flow rate with iterations and the value of the mass flow rate is 0.18904 kg/s.
Design Point 5: 20 mm Lift
Geometry:
The below figure shows the cut view section of the gate valve indicating 20 mm lift.
Mesh:
The below figure shows the cut section mesh of the gate valve and all the elements are of element type tetrahedral.
The below image shows the mesh quality. The quality is good and we can proceed for performing simulations. The mesh parameters are shown in below table:
|
Element Type |
Tetrahedral |
|
Element size |
9 mm |
|
Cell Count |
220214 |
Setup:
same as that in design point 1.
Results:
The below figure shows the residuals and residuals looks good as there are no abnormal fluctuations. It took 419 iterations for convergence.
The below figure shows the pressure contour on the cut plane and the result satisfies the pressure boundary condition.
The below figure shows the velocity contour on the cut plane.
The below figure shows the velocity streamlines on the cut plane.
The below figure shows the variation of mass flow rate with iterations and the value of the mass flow rate is 0.23918 kg/s.
Design Point 6: 25 mm Lift
Geometry:
The below figure shows the cut view section of the gate valve indicating 25 mm lift.
Mesh:
The below figure shows the cut section mesh of the gate valve and all the elements are of element type tetrahedral.
The below image shows the mesh quality. The quality is good and we can proceed for performing simulations. The mesh parameters are shown in below table:
|
Element Type |
Tetrahedral |
|
Element size |
9 mm |
|
Cell Count |
219749 |
Setup:
same as that in design point 1.
Results:
The below figure shows the residuals and residuals looks good as there are no abnormal fluctuations. It took 406 iterations for convergence.
The below figure shows the pressure contour on the cut plane and the result satisfies the pressure boundary condition.
The below figure shows the velocity contour on the cut plane.
The below figure shows the velocity streamlines on the cut plane.
The below figure shows the variation of mass flow rate with iterations and the value of the mass flow rate is 0.29791 kg/s.
The below table shows the variation of mass flow rate at different gate valve lifts.
Valve Lift (mm) `\\dot{m}` (kg/s)
0 0.10181
5 0.12277
10 0.14862
15 0.18904
20 0.23918
25 0.29791
30 0.35551
CONCLUSIONS
The parametric study for different gate valve lift is performed and the mass flow rates at different valve lifts is obtained.