Common Mistakes to Avoid in Valve Design

Creating a top valve design is always a learning experience. In order to avoid common mistakes in the design process, read all the details to know below.

Common Mistakes to Avoid in Valve Design - KB Delta

Valves are structures or components found and used in nearly every industrial process or application. Global energy conglomerates, heavy and automotive equipment manufacturers, and mining companies, rely heavily on valves to function adequately in their day-to-day activities.

The primary aim of a valve is to control the flow of fluid – which may be liquid or gas – by partially/completely modifying or blocking its path. This particular action is generally executed with the pneumatic, electric, mechanical, or hydraulic adjustment of a moving stem or part that has been submerged in the fluid.

The varying conditions under which valves are subjected, as well as their overall significance, make its design a considerable and highly imperative task.

However, some engineers make many mistakes during the valve design process. This could significantly affect its performance or impact the entire system. Here are some of the more common mistakes to avoid in valve design.

 

Failing to Take Full Advantage of the CFD in Order to Improve the Flow of Fluid

As soon as you have estimated the static stress on the valve, you should consider analyzing the dynamics at play for the needed fluid. Pressure loss as a result of turbulence and friction is the most crucial factor to consider here.

If you observe that your valve design gives rise to significant vortices or fluid separation areas, you may have to be careful. This is because this situation could result in a considerable increase in noise and vibration. And this can potentially require the installation of additional machinery or pumps.

The most convenient – and fastest – way to substantially enhance our valve design is by running a transient or steady-state CFD simulation. Be on the lookout for low velocity, high-pressure regions in order to readily pinpoint separated flows and consequently make the necessary modifications to your CAD model.

 

Disregarding the Use of FEM Analysis in Order to Anticipate Stresses

Valves are sturdy and versatile, which is why they are used in a wide range of applications. However, most valves have to contend with extreme temperature changes or multiple pressure levels.

It is only natural that the valve components experience varied stress levels, which significantly shortens their lifecycle. This leads to leaks, cracks, and total failure of the valve in worst-case scenarios.

Engineers can utilize the Finite element method (FEM) simulation as an invaluable tool for refining and enhancing tier valve design, especially in the early stages. It also provides highly constructive data or information on the grade and precise location of stress points.

Calculating these areas of stress by hand may be relatively possible. However, it makes more sense to run a FEM analysis since that will take only a few minutes.

 

Inability to Figure Out Crucial Scenarios in Your Valve Design

Although making use of an ill-fitting valve can generate considerable problems for you or your clients. A much more vital scenario you want to avoid at all costs is valve failure. You need to consider terms like cavitation, water hammer effects, erosion, and high-speed choke when designing a high-quality and durable valve to enhance your processes.

 

Common Mistakes to Avoid in Valve Design - KB Delta

 

The Terms and What They Mean

Let’s take a look at some of these terms and what they mean in relation to your valve design:

 

  • Cavitation (Damage, Erosion, and Noise)

 

Cavitation refers to the formation of cavities or bubbles in fluid because of relatively low pressure. These cavities continue to collapse or implode down the stream, resulting in shock waves, which leads to erosion, noise, and significant damage in some cases.

While the physics involved in these phenomena are far too complicated for this article, removing the risk entirely is incredibly difficult. However, it is possible – and easy – to minimize the possibility of their occurrence via the use of CFD simulation.

You can readily analyze the flow throughout the valve design in order to identify high-speed and low-pressure regions. This enables you to swiftly optimize and then iterate your geometry, thereby putting the best design forward right into physical prototype production.

 

  • Water Hammer Effects

 

Strong pressure waves traveling via a pipe system generate tonal noise, not unlike hammers hitting a wall. This is the phenomenon known as a ‘water hammer effect.’

A ‘water hammer’ – or more appropriately a fluid hammer – occurs when fluid in motion is suddenly forced to change direction or stop, thereby affecting its momentum.

Any valve that closes suddenly or too quickly in a pipe system generates a surge of compression-suction pressure. Mild cases lead to vibration or noise, but it may result in a total collapse of the pipe system in significant cases.

 

  • High-speed Choke

 

‘Choke’ is a situation that occurs within a system when flow velocity suddenly rises or increases to a great extent that it practically matches the speed of sound. This brings about a shockwave, which rapidly decelerates the flow rate, thereby causing a blockage inside the system.

Choke is mostly encountered in gas systems, but it can be avoided via a proper aerodynamic analysis. CFD simulation is a great tool to employ for checking out localized areas of high speed. The results you obtain can be utilized, and this makes it possible to optimize the geometry of valve design for improvements.

 

Making Use of a Valve of Inappropriate Size in Your System

First of all, it is vitally essential to find out the appropriate size of the valve you require when selecting the accessories for a pneumatic or hydraulic system.

If you select and use an under-sized valve, you will most likely encounter additional stress, pressure loss, and increased system resistance. All of these situations can result in much higher costs.

But if you opt for an oversized valve or one that is explicitly designed for a higher flow rate than is required, it will be grossly ineffective.

The way out – or the best solution – is to design a valve, tailoring it for the specific conditions it will be placed under. Thus far, this has been somewhat inaccessible for the majority of engineers.

Severely limited resources available for research, analysis, and testing, the expense and time required in fabricating a working prototype, as well as the time pressure during the phase of product development, have all significantly mitigated the acceptance of CFD simulation software.

This is not often the case these days as there are several cloud-based, user-friendly tools that speed up product development, thereby saving you time and resources.

 

Forgetting Thermal Simulation and the Benefit It Brings to the Table

If your valve is continually exposed to low or high-temperature fluids, thermal simulation can be a highly beneficial analysis. High-temperature gases or liquids can bring about intensified stress on materials.

This could result in a considerable decrease in operating efficiency as well as severe damage to external components via heat transfer. This may include melting plastic components, etc.

Thermal simulation can be considered a form of FEM analysis as certain thermal loads are generally prescribed to the object instead of displacement or pressure.

 

Valve Design Conclusion

These are just some of the common mistakes to avoid in valve design. Consider them carefully, do the needful, and you will begin to see marked improvements in the use of your valves in any of your technical operations.

 


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