Can a Vortex Flowmeter measure gas flow?

As a supplier of Vortex Flowmeters, I often encounter questions from customers about the capabilities of our products. One of the most frequently asked questions is whether a Vortex Flowmeter can measure gas flow. In this blog post, I will delve into this topic, exploring the principles behind Vortex Flowmeters, their suitability for gas flow measurement, and how they compare to other types of flowmeters.

Understanding Vortex Flowmeters

A Vortex Flowmeter operates on the principle of the von Kármán vortex street. When a fluid (either liquid or gas) flows past a bluff body (also known as a shedder bar) placed in the flow path, alternating vortices are shed from the sides of the bluff body. These vortices create a fluctuating pressure field that can be detected by a sensor. The frequency of the vortex shedding is directly proportional to the fluid velocity, and by measuring this frequency, the flow rate of the fluid can be determined.

The relationship between the vortex shedding frequency (f), the fluid velocity (v), and the characteristic dimension of the bluff body (d) is given by the Strouhal number (St):

[St = \frac{f \cdot d}{v}]

The Strouhal number is a dimensionless constant that depends on the shape of the bluff body and the Reynolds number of the flow. For a given Vortex Flowmeter design, the Strouhal number is relatively constant over a wide range of Reynolds numbers, which allows for accurate flow measurement.

Measuring Gas Flow with Vortex Flowmeters

Yes, a Vortex Flowmeter can measure gas flow. In fact, Vortex Flowmeters are widely used for gas flow measurement in various industries, including oil and gas, chemical, power generation, and HVAC. There are several reasons why Vortex Flowmeters are well-suited for gas flow applications:

• Wide Turndown Ratio: Vortex Flowmeters can measure gas flows over a wide range of flow rates, typically with a turndown ratio of 10:1 or higher. This means that a single Vortex Flowmeter can accurately measure both low and high gas flow rates, eliminating the need for multiple flowmeters.
• High Accuracy: Vortex Flowmeters offer high accuracy in gas flow measurement, typically with an accuracy of ±1% of reading or better. This accuracy is maintained over a wide range of operating conditions, including changes in temperature, pressure, and gas composition.
• Low Pressure Drop: Vortex Flowmeters have a relatively low pressure drop compared to other types of flowmeters, such as orifice plates or Venturi tubes. This results in lower energy consumption and operating costs, especially in high-flow applications.
• No Moving Parts: Vortex Flowmeters have no moving parts, which reduces the risk of mechanical failure and maintenance requirements. This makes them a reliable and cost-effective solution for gas flow measurement.

Factors Affecting Gas Flow Measurement with Vortex Flowmeters

While Vortex Flowmeters are well-suited for gas flow measurement, there are several factors that can affect their performance and accuracy:

• Gas Properties: The properties of the gas being measured, such as density, viscosity, and compressibility, can affect the performance of a Vortex Flowmeter. For example, gases with low density or high viscosity may require a different bluff body design or a different calibration to ensure accurate measurement.
• Flow Profile: The flow profile of the gas in the pipeline can also affect the performance of a Vortex Flowmeter. Ideally, the gas flow should be fully developed and uniform across the pipeline cross-section. Any disturbances in the flow, such as bends, elbows, or valves, can cause uneven flow profiles and affect the accuracy of the measurement.
• Temperature and Pressure: Changes in temperature and pressure can affect the density and viscosity of the gas, which in turn can affect the performance of a Vortex Flowmeter. To ensure accurate measurement, it is important to compensate for these changes using temperature and pressure sensors.

Comparing Vortex Flowmeters with Other Flowmeters

When choosing a flowmeter for gas flow measurement, it is important to consider the specific requirements of the application and compare the performance and features of different flowmeters. Here is a comparison of Vortex Flowmeters with two other common types of flowmeters: Turbine Flow Meters and LDG Electromagnetic Flowmeters.

• Turbine Flow Meters: Turbine Flow Meters measure the flow rate of a fluid by measuring the rotational speed of a turbine rotor placed in the flow path. While Turbine Flow Meters offer high accuracy and fast response times, they have several limitations, including a relatively narrow turndown ratio, high pressure drop, and the need for regular maintenance due to the moving parts. In contrast, Vortex Flowmeters have a wider turndown ratio, lower pressure drop, and no moving parts, making them a more reliable and cost-effective solution for gas flow measurement. Turbine Flow Meter
• LDG Electromagnetic Flowmeters: LDG Electromagnetic Flowmeters measure the flow rate of a conductive fluid by measuring the voltage induced by the fluid flowing through a magnetic field. While LDG Electromagnetic Flowmeters are highly accurate and reliable for measuring the flow of conductive liquids, they are not suitable for measuring the flow of gases, as gases are non-conductive. In contrast, Vortex Flowmeters can measure the flow of both liquids and gases, making them a more versatile solution for flow measurement. LDG Electromagnetic Flowmeter

Conclusion

In conclusion, a Vortex Flowmeter can measure gas flow accurately and reliably. With their wide turndown ratio, high accuracy, low pressure drop, and no moving parts, Vortex Flowmeters are a popular choice for gas flow measurement in various industries. However, it is important to consider the specific requirements of the application and the factors that can affect the performance of the flowmeter to ensure accurate and reliable measurement.

If you are in the market for a Vortex Flowmeter for gas flow measurement, I encourage you to contact us to discuss your specific requirements. Our team of experts can help you choose the right flowmeter for your application and provide you with the support and service you need to ensure its successful operation. Vortex Flowmeter

References

• ISO 5167-1:2003, Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full - Part 1: General principles and requirements.
• ASME MFC-6M-2001, Measurement of Gas Flow in Closed Conduits Using Turbine Meters.
• IEC 60534-1:2011, Industrial-process control valves - Part 1: Control valve terminology and general considerations.