Overview
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ABSTRACT
Quantifying the flow rate of a fluid (liquid or gas) often requires integrating velocity measurements distributed throughout a cross-section of the flow. The discharge result is then obtained by the spatial and temporal integration of the velocity field throughout the cross-section and over a given duration. Spatial integration can be done either directly by linear interpolation and extrapolation to the walls, or using standardized weighted average formulas. This article outlines the procedure for measuring liquid free surface flows (stream hydrometry) and fluid flows in closed pipes.
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Read the articleAUTHORS
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Jérôme LE COZ: Researcher (IPEF) - Hydrology-Hydraulics Research Unit, Irstea, Lyon-Villeurbanne, France
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Isabelle CARÉ: Design manager, technical referent for gas flowmetry and anemometry - CETIAT, Studies and Training Division, Villeurbanne, France - Editor's note: This article is an update of the article entitled "Determination of fluid flow by velocity field integration" by Francis DUPRIEZ, published in 1992.
INTRODUCTION
To measure the flow of a fluid (liquid or gas) through a pipe or channel, a global method is used whenever possible. Although there are many such methods, it's not always possible to find a suitable one, or to use it. This applies in particular to closed pipes or large channels, but also to pipes in which it is not possible, for various reasons, to insert a flowmeter. In such cases, it is necessary to record the velocity and geometry in a cross-section and calculate the flow by integration.
Devices, sensors and methods for measuring velocities are described in the article "Local velocity measurements in a fluid"
The purpose of this article is to set out the rules to be followed when taking measurements and calculating flow rates. These rules are laid down in a number of French and foreign standards to which the reader may refer.
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KEYWORDS
fluids | Velocimetry | flow rate | fluid dynamics | integration methods
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Physical measurements
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Determining fluid flow by velocity field integration
Principle of the integration method
Bibliography
Standards and norms
International standards
International Electrotechnical Commission
- Field acceptance tests to determine the hydraulic performance of hydraulic turbines, storage pumps and pump-turbines. - IEC 60041 - 1991
- Hydrometry – Methods for exploring the velocity field using reels – Data collection...
International Organization for Standardization (ISO)
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