PARAMETRIC STUDY OF A GATE VALVE
REPORT ON PARAMETRIC STUDY OF GATE VALVE
Parametric Study:
A parametric study in Simulation is done to Map the change in inputs to the corresponding outputs. As long as the input parameter and output parameters are connected, the corresponding output values for change in input values are obtained.
In our case, the process begins with the creation of an Input parameter group in the SpaceClaim window. The corresponding Parametrized output is the mass flow rate.
Fig 1. The solid model of the Gate valve
Extraction of fluid volume from the model:
The flow volume contained within the gate valve is extracted using the volume extract tool. This extracted volume takes into consideration of the void left behind due to the presence of the gate disc.
Fig 2. The extracted fluid volume from the gate valve model.
Pull tool is used to extend the face of the inlet and outlet of the gate valve.The fluid volume is updated in context with the enclosed edges of the gate disc and stem. By doing so, the fluid volume gets adapted to the model with change in the lift of the gate disc.
Generating the mesh model:
The mesh model is generated using the ANSYS Meshing module using body sizing functions. The mathematical mesh model is refined around the flow regions. The generated mesh model is assigned with inlet and outlet boundary conditions. By default, the other surfaces are assigned wall boundary conditions and the volume is given interior conditions.
Fig 3. The mesh model of the fluid volume.
The statistics of the mesh model are as follows:
No. of nodes: 46258
No. of elements: 228942
Fluent solver:
The meshed model is imported into the mesh model. The simulation is carried out as a steady state simulation with gravity enabled. The various data for the simulation are as follows.
Model used : K-e model with standard wall functions
Cell zone material : water(liquid)
The boundary conditions for the simulation are as follows,
Pressure inlet condition: 15 Pa (Absolute pressure)
Pressure outlet condition: 0 Pa (Absolute pressure)
Surface Report for mass flow output is assigned as the output parameter so that when the inlet parametric group is modified the corresponding change is reflected in the output parameter. Steady state analysis is done until the solution converges. Report plots are also created for the same. The solution is made to run until the mass flow rate becomes constant.
Fig 4. The residual plot after 350 iterations.
Fig 5. The mass flow rate corresponding to 10 mm. lift of the gate disc.
The negative sign indicates that the mass leaves the flow domain.
Parametric Study:
Initially the Parametric Set is defined with the input parameter group. After solving the model in ANSYS Fluent model, the output parameter for the 1st (current) Design point is updated. After updating all the design points, the output parameter is updated for all design points.
Fig 6. The Schematic outline of the parameter group
Fig 7. The Table of design points after updation.
The lift of the gate disc can be seen for each case by changing the current design point.
The different lift values of gate disc for different design points are shown below. The gate disc is highlighted so as to visualize the difference.
Fig 8. Gate disc position for 10 mm. lift
Fig 9. Gate disc position for 15 mm. lift
Fig 10. Gate disc position for 20 mm. lift
Fig 11. Gate disc position for 25 mm. lift
Results from Post-processor:
A plane placed axial to the length of the flow domain is used to plot the velocity graph. The results from the post-processor are as follows.
Fig 12. The velocity contour for 10 mm. lift
Fig 13. The velocity contour for 15 mm. lift
Fig 14. The velocity contour for 20 mm. lift
Fig 15. The velocity contour for 25 mm. lift
Results:
The mass flow rate for the corresponding values of lift are as follows.
DP Lift(mm.) Flow rate(Kg/s)
0 10 .17789
1 15 .22216
2 20 .28305
3 25 .35567