Types of gas flow measurement

Measurement of gas flow is a key point in the field of gas application. In recent decades, thermal mass flow (TMF) meters are widely used in measuring the mass of gas. The TMF meters have many advantages such as wide applicable fields it can be applied to many kinds of pipelines and different types of gasses), wide measurement range, and high measurement accuracy and repeatability.

Thermal mass flow meters generally use combinations of heated elements and temperature sensors to measure the difference between static and flowing heat transfer to a fluid and infer its flow with a knowledge of the fluid’s specific heat and density. The fluid temperature is also measured and compensated for. If the density and specific heat characteristics of the fluid are constant, the meter can provide a direct mass flow readout, and does not need any additional pressure temperature compensation over their specified range.

Today, thermal mass flowmeters are used to measure the flow of gasses in a growing range of applications, such as chemical reactions or thermal transfer applications that are difficult for other flow metering technologies. This is because thermal mass flow meters monitor variations in one or more of the thermal characteristics (temperature, thermal conductivity, and/or specific heat) of gaseous media to define the mass flow rate.

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Aerospace sensing solutions

In every infrastructure, it is important to make sure that the cracks can be detected and monitored earlier in order to avoid any unwanted incident or any deformation of structures. Recently, Fibers Bragg gratings (FBGs) are growing interest in sensing applications such as aerospace, military, structural monitoring, and many others. FBGs are very high accuracy and also high sensitivity.

Over the last two decades, the growth of air traffic has been impressive and will strongly increase in the forthcoming years. Already by 2020, it is expected that aircraft will be significantly more affordable, safer, cleaner, and quieter than at the turn of the century.

In this context, the use of composite materials is essential for the design of high-strength, lightweight aircraft structures, which may contribute significantly to the reduction of fuel consumption and pollutants without compromising flight worthiness.

Nowadays, fiber optic sensors (FOS), particularly those based on fiber Bragg gratings (FBGs), have been emerging as an increasingly interesting technology due to their distinctive advantages which include higher sensitivity, immunity to electromagnetic interference, and durability. Furthermore, their multiplexing capability offers the possibility to reduce dramatically the cumbersome wiring required by electrical strain gauges and accelerometers, traditionally employed for load monitoring.

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