Interaction between the Standard and the Measurement Instrument during the Flow Velocity Sensor Calibration Process

Paweł Jamróz

doi:10.3390/pr9101792

Abstract

The complex ventilation system development process is associated with the stages of modelling, design, execution, and testing. Each of these steps requires the use of measuring equipment that is capable of determining the basic parameters of the flow. In the process of calibrating instruments for measuring flow velocity, one of the limitations is the size of the calibrated devices positioned in the test section of the wind tunnel. This is related to the change in the flow condition within the vicinity of the calibrated anemometers, which is caused by the blockage effect. Instruments with significant dimensions in relation to the cross-sectional area of the wind tunnel test section may have an impact on the reference velocity as indicated by the standard. In such cases, the calibration results may be affected by additional systematic error. This article presents a study of this effect using a real case of a calibration laboratory and commonly used sensors. The influence of different types of air velocity sensors on velocity profiles in the measurement standard area is also investigated. Additionally, the area of the blockage effect is described. The obtained results indicate the possibility of a proper placement for the measuring standard due to minimization of the flow-blocking effect.

Highlights

Having reliable knowledge of flow velocity is of significant importance in many areas related to mass and heat transport
The first is a multi-hole orifice plate, which is used in the range of low velocities
The flow quality and the size of the calibrated instrument may interfere with the measurement standard indications

Summary

Introduction

Having reliable knowledge of flow velocity is of significant importance in many areas related to mass and heat transport. In the case of ventilation measurement, precise velocity flow information is critical to ensure the safety of work in places with limited fresh air access (e.g., mines, tunnels) [1]. It is useful information in making financial decisions like preliminary estimations of the wind energy potential of a site [2]. Many studies have been conducted based on the accurate measurement of flow velocities [3] These include tests performed both in wind tunnels and under real measurement conditions, like studies on the wake effect from wind turbines, turbulent boundary layer research, heat loss experiments, and many others [3,4,5,6]. Ventilation measurement methods and devices are used to determine boundary conditions and validate numerical models in computational fluid dynamics [7]

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Conclusion