Parametric analysis of gate valve with different lift of gate disc conditions

Introduction

A gate valve, also known as a sluice valve, is a valve which opens by lifting 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).

Computational study of gate valve

The selected lift parameter was varied from 0 mm to 25 mm by the step size of 5 mm. This way I got the result for 6 points and it is presented below with velocity contour. The mass flow rate was getting increased as the lift increases and the plot of the same is drawn to show the relation between them. Computational was performed by giving zero lift (Initial condition of the model). The mesh size selected as 8 mm, which gives the total number of elements 499632. The quality of the mesh was pretty good to get finer velocity contour. The steady-state simulation was performed with consideration of gravity force. The realizable k-epsilon viscous model was chosen with scalable wall function active to enhance the results in near wall region. The velocity contour plot and animation are presented for all the design points. In this velocity contour and velocity, the animation was developed for an entire study on the gate with different lift condition.

Parametric Study

The parametric study allows the user to reduce the repeated task and saves time in defining the same physics which contain variations. Ansys workbench allows a user to set such variations as an input parameter and get the desired output as an output parameter. Such parameters can be set at any level of study, starting from geometry to getting the result in the CFD-post. User can run the baseline simulation by setting the input and output parameters and when it gets finished, the user can extend it to defining the design points as per requirement.

Flow condition at different gate disc condition

1. Fully close condition of the gate valve (0mm lift of gate disc)

2. Partially open condition of a gate valve (5mm lift of gate disc)

3. Partially open condition of a gate valve (10mm lift of gate disc)

4. Partially open condition of a gate valve (15mm lift of gate disc)

5. Partially open condition of a gate valve (20mm lift of gate disc)

6. Partially open condition of a gate valve (25mm lift of gate disc)

Design Point	Gate disc lift (mm)	Velocity (m/s)	Mass flow rate outlet (kg/s)
1	0	0.1415488	0.10096
2	5	0.1415488	0.12268
3	10	0.1415488	0.14825
4	15	0.1415488	0.187924
5	20	0.1415488	0.23868
6	25	0.1415488	0.29803

Observation

1. As the lift of gate disc increases, the outlet mass flow rate (kg/s) increases.
2. At the manufacturing, some tolerance is considered for because 100% can\'t achieve. So, zero lift time has some amount of mass flow rate at the outlet, it proves that there is some tolerance exists at the valve which allows some mass to leak.
3. The trendline shows that mass flow rate and lift are almost linearly proportional to each other.