PARAMETRIC STUDY ON THE GATE VALVE SIMULATION
Gate Valve Parametric Study
OBJECTIVE :
- To perform a parametric study on the gate valve simulation by setting the opening from 10 % to 90%.
- To obtain the mass flow rates at the outlet for each design point.
- Calculate the flow coefficient and flow factor for each opening and plot the graph.
SOFTWARE USED:
ANSYS, SpaceClaim - To prepare FV model.
ANSYS, Meshing - To mesh the given model.
ANSYS, FLUNET - To setup the boundary conditions and to solve the given model.
ANSYS, CFD Post - To perform Post Processing.
THEORY :
Gate Valve :
A gate valve, also known as a sluice valve, is a valve that opens by lifting a barrier (gate) out of the path of the fluid. Gate valves require very little space along the pipe axis and hardly restrict the flow of fluid when the gate is fully opened. The gate faces can be parallel but are most commonly wedge-shaped (in order to be able to apply pressure on the sealing surface).
Typical Use :
Gate valves are used to shut off the flow of liquids rather than for flow regulation. When fully open, the typical gate valve has no obstruction in the flow path, resulting in very low flow resistance. The size of the open flow path generally varies in a nonlinear manner as the gate is moved. This means that the flow rate does not change evenly with stem travel. Depending on the construction, a partially open gate can vibrate from the fluid flow.
Types of Gate Valves:
There are three ways to classify the gate valve.
- Types of Disk
- Solid taper wedge
- Flexible wedge
- Split wedge or Parallel disks Valve
- Types of Body Bonnet Joint
- Screwed Bonnet
- Bolted-Bonnet
- Welded-Bonnet
- Pressure-Seal Bonnet
- Types of Stem movement
- Rising Stem or OS & Y Type (Outside Stem and Screw Type)
- Non-rising Stem type
Applications :
- Gate valves are used in almost all fluid services such as air, fuel gas, feedwater, steam, lube oil, hydrocarbon, and all most any services.
- Some special gate valve is used in slurry and powder product also such as knife gate valve.
PROCEDURE :
STEP 1 : GEOMETRY USED
1.Importing the 3D model:
The first step is to import the 3D model to the space claim.
PARTS Description :
Section View :
Front_sectional_view Section_side_view
2.Volume extraction:
Fluid volume extraction is defined as extracting the volume of the fluid .
In this case,we are extracting the volume of the fluid region.
STEP 2 : MESHING
Naming Parts :
STEP 3 : SET UP & SOLUTION
Here we going to present the contours for few cases ( i.e for Lift height @ 10mm ; 50mm ; 90mm) in order to reduce complexity.
Gate Valve Lifting Height Variations :
Residuals Plot :
Mass_Flow Rate :
Right Hand side : Outlet
Left Hand Side : Inlet
Case 1 : GateValve_Liftheight = 10mm
1.Velocity Contour & Streamlines @ 10mm :
2.Velocity Contour & Streamlines @ 20mm :
3.Velocity Contour & Streamlines @ 30mm :
4.Velocity Contour & Streamlines @ 40mm :
5.Velocity Contour & Streamlines @ 50mm :
6.Velocity Contour & Streamlines @ 60mm :
7.Velocity Contour & Streamlines @ 70mm :
8.Velocity Contour & Streamlines @ 80mm :
9.Velocity Contour & Streamlines @ 90mm :
The flow coefficient of a device is a relative measure of its efficiency at allowing fluid flow. It describes the relationship between the pressure drop across an orifice valve or other assembly and the corresponding flow rate.
K = Cv, when K is referenced in [gpm] [psi] units.
K = Kv, when K is referenced in [m³/h] [bar] units.
where:
Q is the rate of flow ,
SG is the specific gravity of the fluid (for water = 1),
ΔP is the pressure drop across the valve
Relation between Kv & Cv
Kv can be calculated from Cv using the equation:
TABULATION :
In this case:
Qtotal = 1 kg/s = 3.6 m^3/h
Sg for water = 1,
Δp is in pa
Table 1 :