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Documentation

# Validation Case: Butterfly Valve

This validation case belongs to fluid dynamics and the aim of this case is to validate the following parameters inside a pipe with a butterfly valve:

• Pressure drop
• Torque

The simulation results of SimScale were compared to the results presented in the study done by Song, Xue Guan and Park, Young Chui with the title “Numerical Analysis of Butterfly Valve – Prediction of Flow Coefficient and Hydrodynamic Torque Coefficient“$$^1$$.

## Geometry

The model used in this validation case is a pipe with a discus shaped butterfly valve inside, which can be seen below: Figure 1: Pipe model with butterfly valve inside opening at 20° angle

The dimensions of the pipe can be seen in the table below:

9 variants of valve opening angles ranging from 20° to 85° were used as a comparison to the reference study.

## Analysis Type and Mesh

Tool Type: OpenFOAM®

Analysis Type: Steady state, Incompressible with K-Omega SST turbulence model

Mesh and Element Types:

The mesh was created with SimScale’s Standard mesher and the following table lists the details of the mesh: Figure 2: Mesh of flow domain with fineness level 7

Furthermore, region refinements were also added in the area near the hinges of the valve so the calculation in those areas can be done accurately. Figure 3: Standard meshing performed on valve with refinements at hinges

## Simulation Setup

Fluid:

• Water
• Kinematic viscosity $$(\nu)$$: 9.338e-7 $$m^2/s$$
• Density $$(\rho)$$: 997.3 $$kg/m^3$$

Boundary Conditions: Figure 4: Boundary condition overview where flow goes from left to right

The boundary conditions are the same for all opening angles and were assigned as shown in Table 3:

## Reference Solution

The reference solution for the flow coefficient and the torque coefficient is given in the following formulae:

Flow coefficient:

$$c_v = \frac{Q}{\sqrt{\Delta P \times S_g}} \tag{1}$$

where:

• $$c_v$$: flow coefficient
• $$Q$$: flow discharge $$(GPM-Gallons\,per\,minute)$$
• $$\Delta P$$: pressure drop $$(psi)$$
• $$S_g$$: specific gravity of water

Torque coefficient:

$$c_t = \frac{T(x)}{\Delta P \times d^3} \tag{2}$$

where:

• $$c_t$$: torque coefficient
• $$T(x)$$: torque in the x-axis $$(N.m)$$
• $$\Delta P$$: pressure drop $$(psi)$$
• $$d$$: diameter of pipe $$(in)$$

## Result Comparison

Comparison of the flow and torque coefficients obtained from SimScale against the reference results obtained from  is given below: Figure 5: Flow coefficient comparison between reference results and SimScale Figure 6: Torque coefficient comparison between reference results and SimScale

The flow contours inside the pipe when the valve is opened at the simulated opening angles as observed in our online post-processor: Figure 7: Velocity magnitude contours inside the pipe at the centerline when the valve is opened at a 20° – 50° angle. Figure 8: Velocity magnitude contours inside the pipe at the centerline when the valve is opened at a 60° – 85° angle.

Note

If you still encounter problems validating you simulation, then please post the issue on our forum or contact us.

Last updated: March 16th, 2022