Week 9 - Parametric study on Gate valve.

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Parametric Study: -

A parameter is a numerical or other measurable factor that help to define a particular system. A parameter is linked to a data model property within an application. You can have input and output parameters. Parameter values can be numeric or non-numeric (string or Boolean). Non-numeric parameters are ignored for charting purposes. An input parameter can be modified at the project level and drives a change within the data model. The value of an output parameter is set by the application, based on the current results or state.

• Input parameters define the geometry or inputs to the analysis for the system under investigation. Input parameters have predefined values or ranges that may be changed. These include CAD parameters, analysis parameters, and DesignModeler parameters. CAD and DesignModeler input parameters include length and radius. Analysis input parameters include pressure, material properties, and sheet thickness.
• Output parameters result from the geometry or are the response outputs from the analysis. These include volume, mass, frequency, stress, velocities, pressures, forces, and heat flux.

Custom Parameters are project-level parameters that are not directly associated with a data model property. They can be a custom input or custom output parameter that is defined by a constant value, such as `sin(pi/2)` Or, they can be a derived parameter, defined by an expression of other parameters, such as`P2+3*P3.` For more information, see Expressions, Functions, Quantities, and Units.

All parameters have a quantity, preferably with a quantity name. The quantity name is used to define preferred and available units for the quantity. If the value does not have a quantity name defined, Workbench displays the value without units.

You can add parameters to or delete them from the current project. However, this may set existing design points and design exploration systems to an out-of-date state and can result in several hours of recalculation time, depending on the project. Be aware that deleting a parameter referenced in the expression of another parameter invalidates the driven data model, resulting in an error.

Flow coefficient:-

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.

Mathematically the flow coefficient `C_v` can be expressed as :

`C_v = Q*sqrt((SG)/(triangle P))`

where:

`Q` = Rate of flow (expressed in US gallons per minute),

` SG` = Specific gravity of the fluid (for water = 1),

`triangleP`= Pressure drop across the valve (expressed in psi).

The metric equivalent flow factor (K_v; commonly used everywhere else in the world with the exception of the United States) is calculated using metric units :

`C_v = Q*sqrt((SG)/(triangle P))`

where:

`K_v` = Flow factor (expressed in `m^{3}.h^{-1}`).

`Q` = Flowrate (expressed in cubic metres per hour `m^{3}/h`),

` SG`= Specific gravity of the fluid (for water = 1),

`triangleP` = Pressure difference across the device (expressed in [bar]).

`K_v` can be calculated from `C_v` using the equation:

`K_v=0.865*C_v`

Aim:- To perform a parametric study on Gate value simulation by setting the opening from 10 % to 80%. Obtain the mass flow rate, flow coefficient, and flow factor at the outlet for each opening design point.

Procedure:-

1. Geometry preparation
2. Meshing
3. Setup & Solution
4. Results

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1. Geometry preparation:

• Open Spaceclaim and import the Gate valve 3-D model.
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• 
• Hide the bottom
• Parameterising Gate Disc lift:
  • Design => Move
    • Move Component select Gate Disc
      • The coordinate system will appear on the body Pull the Green co-ordinate axis towards the top of the spindle.
      • Enter value = 10 mm.
      • 
      • If you see `P` beside Value enter Press to parameterize the raise of the gate disc.
    • An alternate way to parameterize the Gate Disc raise.
      • 
      • Go to the Groups menu which is adjacent to the Structure menu
      • In the Group menu, you will be able to see the Create Parameter button, which will be enabled only after you have moved the gate disc.
      • Click on the Create Parameter following which you will see a Group-1 appear in which you can edit the dimensions of the lift.
      • Edit Group-1 name to Gate Disc Lift
• Extending the coupling sides of the bottom which will act as inlet and outlet pipe.
  • Design => Pull
    • Select Inlet face and pull up to 800 mm.
    • Select Outlet face and pull up to 800 mm.
  • 
• Use the Volume extract command to extract the Fluid domain.
• Volume extract
  • Hide Bonnet for better selection of top boundary
  • Edge selection(Select boundaries)
    • Create volume Enclosure from the selected boundaries
      • Fluid domain extracted.
      • 
• Section View:-
  • 
• Hide all Gate valve components and suppress them for physics so that they are not going to participate in the calculation part.
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• Conforming Parameterized Gate Disc Lift with Workbench.
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2. Meshing:

• Creating Named Sections:
  
  • Inlet
  • Outlet
    • 
  • Generate Mesh with element size = 7 mm
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• Element Quality:
  • 
• Statistics:
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3. Setup & Solution:-

1. Double Precision, Solve processers = 4.
2. Solver
   • Type = Pressure Based
     • Velocity Formulation = Absolute.
       • Time= Steady
3. Gravity = on
   • `Z =−9.81m/s^2`
4. Materials:
   • Water
     • Density :- `998.2 [Kg/m^3]`
     • Viscosity :- `0.001003 [(Kg)/(m-s)]`
5. Cell zone conditions:-
   • material name = Water
6. Boundary conditions:-
   • Typically for pipe flows 10-pascal pressure is acceptable.

   • 	Type	Momentum
     Inlet	Pressure inlet	Guage Total pressure = 10 [Pa]
     Outlet	Pressure Outlet	Guage Total pressure = 0 [Pa]
     	Wall Motion	Shear Condition
     Wall	Stationary Wall	No-slip
7. To find the type of viscous model we need to calculate Renolds number but in this problem, we used inlet type as pressure inlet of 10 Pascal.
   • To know the inlet velocity go to the
     • initialization => Standard Initialization
     • Compute from => Inlet
     • where you can find the inlet velocity magnitude.
     • 
       • Reynolds Number Calculation
         • `R_e = (rho*V*D)/mu`
           • `text(Density of water ) rho = 998.2 (Kg)/m^3`
           • `text(Inlet Velocity ) V = 0.1415488 m/s`
           • `text(Pipe Dia ) D = 0.1 m`
           • `text(Viscosity ) mu = 0.001003 [(Kg)/(m-s)]`
         • `R_e = text(998.2 * 0.1415488 * 0.1)/0.001003 = 14087.1397 > 2000`
         • `R_e` is Greater than 2000 so we can go for Turbulent viscous model.
8. Viscous model
   • k-Epsilon
     • Realizable
       • Scalable Wall Functions.
9. Residual monitors:
   • uncheck the convergence
10. Report Definitions:-
    • New Report => Flux report definitions
      • Mass Flowrate report
      • Boundary => Outlet
      • Create
        • Report File
        • Report Plot
        • Output Parameter
          • By Enabling the output parameter calculation result gets updated to the workbench.
    • 
    • 
11. Initialization methods:-
    • Standard Initialization
      • Compute from = Inlet.
12. Contours and Animations:-
    • To plot velocity and pressure contours, we need a plane surface.
      
      • Create => Plane
      • 
    • Create Velocity and pressure contours on the above plane.
13. Run Calculations:-
    • Steady-State Simulation
      • 

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4. Parameters & Design Point setting:-

• Parameters:-
  • 
• Design Points Calculation:
  • Parametric study on the gate valve simulation by setting the opening from 10 % to 80%.
  • Pipe Diameter = 100 mm

    • Design Point	Opening Percentage (%)		Gate Disc Lift (mm)
      0	10%	0.1*100	10 mm
      1	20%	0.2*100	20 mm
      2	30%	0.3*100	30 mm
      3	40%	0.4*100	40 mm
      4	50%	0.5*100	50 mm
      5	60%	0.6*100	60 mm
      6	70%	0.7*100	70 mm
      7	80%	0.8*100	80 mm

• Design point setting:-
  • Add Design points by entering magnitudes in the input section.
  • Enable the retain option so that each saves individually.
  • Before Updating All Design Points open Spaceclaim and unhide all bodies. so, that we will not get any issues while updating calculation for each design point movement.
  • 

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5. Results:-

1. Design Point = 0

   10 % Opening

   Lift = 10 mm

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2. Design Point = 1

   20 % Opening

   Lift = 20 mm

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3. Design Point = 2

   30 % Opening

   Lift = 30 mm

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4. Design Point = 3

   40 % Opening

   Lift = 40 mm

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5. Design Point = 4

   50 % Opening

   Lift = 50 mm

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6. Design Point = 5

   60 % Opening

   Lift = 60 mm

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7. Design Point = 6

   70 % Opening

   Lift = 70 mm

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8. Design Point = 7

   80 % Opening

   Lift = 80 mm

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For all the cases

• Flow Coefficient
  • `C_v = Q*sqrt((SG)/(triangle P))`
• Flow Factor
  • `K_v=0.865*C_v`
• ` SG`= Specific gravity of the fluid =`1000/9898.2 ~= 1`
• `triangleP` = Pressure drop across the device = 10 pascal
  • 1 Pascal = 1e-5 Bar
• `Q = text(Flow rate) (kg)/s`
  • 1 kilogram (water mass) per second to cubic meters per hour = 3.60 m3/h

Result Table:

Design Point	Gate Disc Lift `(mm)`	Mass Flow rate `(Kg/s)`	Mass Flow rate `(m^3/h)` `[text(1Kg[water mass])]/s = 3.6 m^3/h`	Specific gravity of Water	Pressure Drop [Pa]	Pressure Drop [Bar] 1Pascal = 1e-5 Bar	Flow Coefficient `C_v = Q*sqrt((SG)/(triangle P))`	Flow Factor `K_v = 0.865*C_v`
0	10	0.14993	0.539748	1	10	0.0001	53.9748	46.6882
1	20	0.23888	0.859968	1	10	0.0001	85.9968	74.38723
2	30	0.36309	1.307124	1	10	0.0001	130.7124	113.0662
3	40	0.47766	1.719576	1	10	0.0001	171.9576	148.7433
4	50	0.5662	2.03832	1	10	0.0001	203.832	176.3147
5	60	0.64318	2.315448	1	10	0.0001	231.5448	200.2863
6	70	0.72189	2.598804	1	10	0.0001	259.8804	224.7965
7	80	0.79344	2.856384	1	10	0.0001	285.6384	247.0772

Plots:-

• Flow Coefficient & Flow Factor Vs Gate Lift
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• Flow Coefficient & Flow Factor Vs Gate Lift
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Conclusions:

• Successfully simulated & analyzed parametric study on Gate valve.
• As the Gate Valve lift Increases Mass flow rate at the outlet and the Flow Coefficient increase.