Performance Evaluation of Ball Valve for different V-port Angles
Wednesday, March 25, 2020
Blog Author - Aaditya Ruiker
Written by Aaditya Ruiker
Approximately
15 Minutes Reading
Approximately
15 Minutes Reading
The V-ball or V-port ball valve is similar to a conventional ball valve where a V-notch is provided on a ball-shaped disk to control flow using a rotational quarter-turn motion. V "port" is an exclusive design that provides precise flow with the ability to modulate and control the flow with 15°, 30°, 45°, 60° or 90° degree V "notches". These control valves are used extensively in chemical applications, including the most challenging services for numerous advantages.
Advantages of a V- port ball valve:
Flow control
The precision of V-Ball valves offers equal percentage flow characteristics that are generally not associated with a standard ball valve.
 Percentage Opening area with Percentage opening angle in V-port ball valve
Bubble tight shut-off
V-ball valves have the capability of tight shut-off. Thus, additional shut-off valves are not required when using a V-ball valve over globe control valves.
Lower pressure drop
V-Ball valves also have higher flow coefficients (Cv) compared to the same size globe valve which diverts flow and uses a plug to control the flow through the valve. This means that smaller V-Ball sizes can be used to achieve the same flow rate as a larger size globe valve.
Higher shut-sff pressure
The 90° ball rotation allows the V-Ball to shut off at higher working pressures. Thus, allowing lower torque actuators to be used, resulting in cost-saving and higher efficiency for the end-user.
Role of Autonomous Valve CFD in design analysis
As the v-port ball valves are used for the precise control over the flow, it is necessary to analyze them and be sure about their performance in terms of pressure drop and the flow-rate. CFD simulations are beneficial for valve designers in the early stages of design processes without manufacturing actual prototypes. But due to very high computer hardware costs and sophisticated numerical methodologies, CFD may not be the practical solution for them.
Autonomous Valve CFD app is designed in such a way that helps valve designers to focus on valve design and leave the task of performing the CFD simulation as per the flow-loop testing methodologies to the app. Using simulationHub valve designers able to :
Run a valve simulation for all the opening angles with just one click
Focus on designing the valve geometry rather than sophisticated CFD methodology.
Analyze and update design quickly to reduce the entire design cycle time.
Access their design from multiple locations and share them among the team members.
Here, I am presenting the design of experiments (DOE) performed for the different configurations of ball V "notches" and the predicted flow performance characteristics over the full range of opening starting from zero to 90°.
Geometry and flow loop testing setup
The 10-inch ball valve with different V-port configurations ϕ[15°, 30°,45°,60°, and 90°] are simulated using the Autonomous Valve CFD app. The flow direction in such a way that V-port is downstream of the valve and ball rotated from V-port to the arc.
Geometry and simulation setup used for the simulation
V-port ball valve configurations simulated using Autonomous Valve CFD
User-defined inputs:
Standard schedule-40 pipe diameter pipe connections were attached to the valve body.
The pipe lengths used in the simulation are 2.5D upstream and 10D downstream of the valve, where D is the nominal pipe size diameter.
The roughness of the pipe and valve body is considered to be 45.72 microns with a smooth ball surface.
Standardization of virtual flow-loop testing in CFD methodology
Autonomous Valve CFD follows ANSI/ISA standards and experimental flow conditions in CFD methodology to replicate flow loop testing virtually.
All CFD processes CAD-cleanup, fluid volume extraction, meshing were run in the simulationHub cloud-platform automatically. The following are the details of the number of simulations completed for the design of iterations.
Simulation Details table
Once the simulations are completed we are ready to analyze the results obtained.
Analyzing results
In general, the flow performance of the valve is evaluated using flow coefficient (Cv), which is the function of flow-rate and pressure drop. The effect of V-ports on the flow coefficient, Cv, can be found in following figure.
: Flow characteristic (Cv) curves with valve opening angle (theta) and V-port
                                        angle (phi)
Following are the observations:
It shows that Cv increases with an increase in valve opening and V-port angle(ϕ).
V-port seems to be the most appropriate one for the equal percentage flow performance control over the round port ball valve.
It can also be observed that for low angle V-port valves provide better control for the low flow-rate applications.
Comparison of flow velocity contours for the V30 and V90 ball valve at 40°
                                        opening angle
Although the narrow V-port can control the volume flow rate linearly or equal percentage , it also can induce cavitation in the flow even though the ball valve is fully open. Figure 5 has observed sharp velocity contours in comparison flow-contours of V30 and V90 ball valves. This increases the very high localized pressure and chances to induce a cavitation prone zone.
Observations :
The V-port ball provides an inherent equal percentage flow characteristic.
It is observed that cavitation indices increase as the angle of V-port decreases.
simulationHub valve CFD made the valve designer’s job easy to carry out a number of design iterations.
Blog Author - Aaditya Ruiker
Aaditya Ruiker
Aaditya Ruiker is a CFD support Engineer at Centre for Computational Technologies Private Limited (CCTech), Pune. He loves to work in fields physics and mathematics. Skilled in OpenFOAM, Fluent, C, MATLAB, CAD Modelling. He has completed his M.Tech in Thermal and Fluids Engineering from (Dr. BATU), Lonere, Raigad. His areas of interest are Heat Transfer, Fluid Mechanics, Computational Fluid Dynamics, Numerical Methods, Operation Research modeling. Driving and traveling, playing cricket and chess are his hobbies and he likes to explore historical places.
Blog Author - Aaditya Ruiker
Aaditya Ruiker
Aaditya Ruiker is a CFD support Engineer at Centre for Computational Technologies Private Limited (CCTech), Pune. He loves to work in fields physics and mathematics. Skilled in OpenFOAM, Fluent, C, MATLAB, CAD Modelling. He has completed his M.Tech in Thermal and Fluids Engineering from (Dr. BATU), Lonere, Raigad. His areas of interest are Heat Transfer, Fluid Mechanics, Computational Fluid Dynamics, Numerical Methods, Operation Research modeling. Driving and traveling, playing cricket and chess are his hobbies and he likes to explore historical places.
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