GATE VALVE PARAMETRIC STUDY

                                                                                                                   PARAMETRIC STUDY ON GATE VALVE

Gate Valves:-

Gate valves are primarily designed to start or stop flow, and when a straight line flow of fluid and minimum flow restrictions are needed. In service these valves generally are either fully open or fully closed. The disc of a gate valve is completely removed when the valve is fully open i.e the disc is fully drawn up in the valve bonnet. This leaves an opening for flow through the valve at the same inside diameter as the pipesystem in which the valve is installed. A gate valve can be used for a wide range of liquids and provides a tight seal when closed.

Model:-

Parametric Study:-

Ansys Workbench uses parameters and design points to allow us to run optimization and what-if scenarios. We can define both input and output parameters in Ansys Fluent that can be used in Ansys Workbench project. As long as the input and output parameters are connected, the corresponding ouput values for the change in input values are obtained.

Extraction of Fluid volume from the model:-

To start with the solution of the problem the fluid volume is extracted using volume extract tool. The pull tool is used to extend the face of the inlet and outlet of the gate valve. It is made sure that the fluid volume is updated in context with the enclosed edges of the gate disc and the stem, so that the fluid volume gets adapted with respect to the changes made in the lift of the gate disc.

The lift of the gate disc is set as parameter input (which changes for every case), is shown in the figure below:-

Meshing:-

The mesh model is generated using ANSYS meshing module by keeping the mesh size as 6mm.

Further the inlet and outlet are assigned as follows.

Setting up the problem:-

For Analysis, Pressure based, steady state solver is used. Gravity is enabled in negative Z direction. The material used in the volume zone is water (liquid). The boundary condition used is pressure inlet with 10 pascal at the inlet.  Also viscous model viz Realiziable k-epsilon with scalable wall function is used. The mass flow rate at output is created as the output parameter.

The problem is initialized using standard initialization and further solved for 250 iterations for different design points (dp) as follows.

Design Point 0 (dp 0) :- Lift = 0mm

Cut-Section View:-

Velocity Contour:-

Velocity Contour Animation:-

Design Point 1 (dp 1) :- Lift = 5mm

Cut-Section View:-

Velocity Contour:-

Velocity Contour Animation:-

Design Point 2 (dp 2) :- Lift = 10mm

Cut-Section View:-

Velocity Contour:-

Velocity Contour Animation:-

Design Point 3 (dp 3) :- Lift = 20mm

Cut-Section View:-

Velocity Contour:-

Velocity Contour Animation:-

Design Point 4 (dp 4) :- Lift = 25mm

Cut-Section View:-

Velocity Contour:-

Velocity Contour Animation:-

Design Point 5 (dp 5) :- Lift = 30mm

Cut-Section View:-

Velocity Contour:-

Velocity Contour Animation:-

Mass Flow rate at the outlet for each design point:-

From the above design point table we can conclude that as the lift of the gate disc increases the mass flow rate also increases. Negative sign of mass flow indicates flow is in taking place towards outward direction.