Week 9 - Parametric study on Gate valve.

Aim -

To perform a parametric study on the gate valve simulation by setting the opening from 10 % to 80%.

• 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.
• Discuss the results of the mass flow rate and flow coefficient.

Introduction -

Gate valve basically employed in the flow to control the flow of fluid in pipe . In this challenge we will be varying the valve position from 10 % - 80 % and will check the mass flow rate variation and pressure drop. The variation of velocity and pressure will be analysed at the end .

Parametric study -

It is study in which once we setup the case we can generate different output for different defined inputs . We dont need to set the case setup again and again. It saves the tim eof simulation as well.

Geometry –

Import the geometry in space claim and extract the volume.

Do the volume extraction for better understanding of the fluid .

Initially we provide the 10mm lift for the disc and extend the volume.

Meshing -

Define the inlet and outlet of the pipe and do meshing of element size of 20 mm.

Setup

Solver Type – Pressure based and Steady

velocity formulation – Absolute

Tick marks the gravity and define the gravitational acceleration as - 9.81 m/sec.

Material - Water fluid

Viscous Model –

Boundaries -

Inlet - Pressure based , 10 Bar

Outlet - Pressure based

Initialization - Standardised , Defined at inlet .

No of iteration - 250 nos

Results - As in this study we will varies the disc opening position from 10 % to 80 % , The valve geometry , pressure and velocity contour for each case is shown below.

For 10 % lift

Pressure Contour

Velocity Contour

For 20 % lift

Pressure Contour

Velocity Contour

For 30 % lift

Pressure Contour

Velocity Contour

For 40 % lift

Pressure Contour

Velocity Contour

For 50 % lift

Pressure Contour

Velocity Contour

For 60 % lift

Pressure Contour

Velocity Contour

For 60 % lift

Pressure Contour

Velocity Contour

For 70 % lift

Pressure Contour

Velocity Contour

For 80 % lift

Pressure Contour

Velocity Contour

flow coefficient and flow factor

Flow Coffcient –

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.

Q is the rate of flow (expressed in US gallons per minute)

SG is the specific gravity of the fluid (for water = 1),

ΔP is the pressure drop across the valve (expressed in psi).

Flow Factor -

The metric equivalent flow factor (Kv) is calculated using metric units :

K_v is the flow factor (expressed in m³·h⁻¹).

Q is the flowrate (expressed in cubic metres per hour m³·h⁻¹)

SG is the specific gravity of the fluid (for water = 1)

∆P is the differential pressure across the device (expressed in bar).

Flow cofficient for different valve disc position

Lift of disc	Mass flow rate (kg /sec)	Flow rate m3 / kg	Flow rate in Gallon	Pressure drop	CV
10	0.23800585	0.85682106	3.77247174	0.001380394	101.5370253
20	0.36035372	1.297273392	5.711726099	0.001288463	159.1224004
30	0.46725997	1.682135892	7.406225655	0.001181698	215.4485614
40	0.55514387	1.998517932	8.799214647	0.001058608	270.4433644
50	0.61783879	2.224219644	9.792949944	0.000976024	313.4608193
60	0.71241108	2.564679888	11.29195214	0.000820275	394.2658563
70	0.76679523	2.760462828	12.15395897	0.000721262	452.5548964
80	0.8252434	2.97087624	13.08038187	0.000603433	532.4832676

Flow Factor for different valve disc position

Lift of disc	Mass flow rate (kg /sec)	Flow rate m3 / kg	Pressure drop	KV
10	0.23800585	0.85682106	9.51747E-05	87.82728845
20	0.36035372	1.297273392	8.88363E-05	137.6373683
30	0.46725997	1.682135892	8.14751E-05	186.3582558
40	0.55514387	1.998517932	7.29883E-05	233.927548
50	0.61783879	2.224219644	6.72944E-05	271.1366981
60	0.71241108	2.564679888	5.65559E-05	341.0312738
70	0.76679523	2.760462828	4.97292E-05	391.4500084
80	0.8252434	2.97087624	4.16052E-05	460.5862874

Plot CV vs Disc Lift

Plot kV vs Disc Lift

Plot kV , cv vs Disc Lift

Mass flow rate vs Disc Lift

Conclusion -

1. It is observed that as we increases the disc lift the mas flow rate also increases . The pressure drop also reduces as we increase the valve disc height .

2. The flow factor and coffcient also found increases as we increases the opening of the disc.

3. The variation in th velocity and pressure is also evident from the contour charts.

4. In this we did the Parametric study in this task we come to know that with this feature we can get different desired output for different inputs with once case setup only.