Measuring device for determining the flow rate of a fluid comprising a liquid phase and a gas phase
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Solution Overview
Problem
Existing flow measurement technologies for vapor phases, such as steam, often encounter interference from film flow where liquid settles on the measuring tube wall, leading to inaccurate measurements.
Innovation Solution
A measuring arrangement with a measuring tube having an inflow area, a central area with a larger cross section, and an outflow area, where the sensor element is positioned in the central area to collect and separate liquid and gas phases, allowing for individual phase flow velocity measurement without disturbance from circumferential liquid films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional flowmeter is used to measure vapor flow, then the measurement can be performed, but liquid film flow on the tube wall interferes with the measurement accuracy
Solution Approach 1:
The measuring tube is divided into distinct functional zones: an inflow area, a central measuring area with larger cross-section, and an outflow area. This segmentation allows the liquid phase to be separated and collected in a channel at the bottom of the central area, preventing it from forming interfering films on the tube wall where the sensor operates.
Solution Approach 2:
A liquid collecting channel is introduced as an intermediary structure within the measuring tube. This channel acts as a mediator that captures and removes liquid phase from the measurement zone, preventing direct contact between the liquid film and the sensor element, thereby eliminating the interference.
2Measurement precision
If the measuring tube cross section is enlarged in the central area, then liquid components can be completely transferred into a channel for separation, but the device complexity increases
Solution Approach 1:
The measuring tube features local quality variations: the central measuring area has a larger cross-section specifically designed for phase separation, while the inflow and outflow areas maintain standard dimensions. This localized modification allows effective liquid-gas separation without requiring complete redesign of the entire tube structure.
Solution Approach 2:
The invention utilizes the radial dimension by introducing a liquid collecting channel at the bottom of the central area. This dimensional approach allows liquid to be directed downward into the channel while gas flows horizontally through the measuring section, achieving phase separation without complicating the primary flow path.
3Measurement precision
If the measuring tube is oriented horizontally with inflow and outflow at the same height, then gravity can effectively separate liquid and gas phases, but the installation requirements become more restrictive
Solution Approach 1:
The measuring tube is designed to be installed horizontally with the inflow and outflow areas at the same height, creating an equipotential condition for gravity-based phase separation. This orientation allows liquid and gas phases to separate naturally along the horizontal flow path without requiring vertical elevation changes, simplifying the separation mechanism while maintaining installation flexibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate measurement of both liquid and gas phase flow velocities, preventing film flow interference and allowing for precise determination of flow rates in vapor mixtures.
Implementation Method 1
the measuring tube of the measuring arrangement, when installed, has an orientation in which the inflow area and the outflow area are arranged essentially at the same height with respect to gravity
Implementation Method 2
the vapor can thus be separated into a liquid phase and a gas phase and the liquid can be transported to the lower area of the measuring tube
Implementation Method 3
a fill level of the measuring tube is deduced from signal reflections of an ultrasonic signal at a pipeline-medium interface and a liquid-gas interface
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a measuring assembly for determining the flow speed of at least one liquid phase (φ2) and/or a gaseous phase (φ1) of a vapor or of a fluid consisting of a liquid and a gaseous phase or of a supercritical fluid, wherein the measuring assembly has a measurement tube (5), on or in which at least one sensor element (10A, 15A) of at least one first flow-through measuring device (10, 15) is arranged, for determining the liquid phase (φ2) or the gaseous phase (φ1), wherein the measurement tube (5) has at least an inflow region (1) and an outflow region (2), wherein between said two regions a center region (7) is arranged, the measurement tube cross-section of which has a greater area content than the area content of measurement tube cross-section of the outflow region (2) or of the inflow region (1). The invention further relates to a method for determining a flow rate of individual phases of a vapor or of a fluid consisting of a liquid and a gaseous phase or of a supercritical fluid.