Acoustic Flowmeter Vortex Shedding for Nuclear Reactor Core
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Solution Overview
Problem
Current methods for measuring fluid flow in nuclear reactors, such as heat-balance derivation, provide only general and non-precise values, necessitating direct and precise measurements for accurate core flow verification and safety compliance, especially in large reactors like ESBWR.
Innovation Solution
Acoustic flowmeters using induced vibration or sound in fluid flow, with extensions and detectors to calculate flow rates through vortex shedding or standing wave frequencies, allowing for direct monitoring and verification of fluid flow in inaccessible reactor spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If heat-balance derivation is used to measure fluid flow, then the measurement method is simple and does not require direct instrumentation, but the measurement precision is insufficient and provides only general values
Solution Approach 1:
The patent replaces complex mechanical flow measurement instruments with acoustic wave-based measurement. Acoustic waves are transmitted through the fluid and the Doppler shift or attenuation of these waves is used to determine flow velocity, eliminating the need for intrusive mechanical sensors while achieving precise measurements.
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium to measure fluid flow. Instead of directly measuring flow with complex instruments, acoustic waves serve as a mediator that interacts with the fluid flow, and the changes in acoustic properties (frequency, amplitude) reveal flow information with high precision.
2Measurement precision
If direct flow measurement instruments are installed in inaccessible reactor spaces, then measurement precision improves, but the device complexity and installation difficulty increase
Solution Approach 1:
The patent replaces intrusive mechanical flow meters with non-intrusive acoustic measurement technology. Acoustic transducers can be positioned externally or in accessible locations, transmitting sound waves through the fluid without requiring direct installation in inaccessible core regions, thereby maintaining measurement precision while simplifying installation.
Solution Approach 2:
Acoustic waves serve as an intermediary that can traverse inaccessible spaces without requiring physical instrumentation in those difficult-to-reach areas. The waves propagate through the fluid medium, allowing measurement from accessible locations while obtaining data from inaccessible regions.
3Adaptability or versatility
If multiple extensions with unique oscillation frequencies are used to cover a range of flow speeds, then the measurement range increases, but the device complexity increases
Solution Approach 1:
The patent divides the measurement range into multiple segments, each handled by a specific extension geometry tuned to particular flow velocity ranges. Different extension shapes (cylindrical, conical, annular) with specific dimensions are used to cover different Reynolds number ranges, allowing the system to maintain high measurement accuracy across the entire flow spectrum without requiring a single complex device.
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 precise and direct measurement of fluid flow, enhancing core safety compliance and operational strategy by providing accurate flow data, especially during startup, shutdown, and transient scenarios.
Implementation Method 1
a detector that picks up vibrations caused by vortex shedding around the extension
Implementation Method 2
A vibration detector and processor can transform the vibration frequency into a flow rate of the fluid through the flowmeter
Implementation Method 3
The turbulence or vorticing in the flow at the outlet create a standing wave in the fluid flow, which induces vibration in the extension and/or entire flowmeter
Data Source
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AI summary
acoustic flowmeters and methods of using the sameacoustic flowmeters and methods of using the sameVibration-based flowmeters are useable in inaccessible nuclear reactor spaces. Flowmeters include an extension that blocks fluid flow 'in a path and a detector that detects vibrations caused by vortex shedding in the fluid flow around the extension. The detected frequency of the vibrations determines the flow rate, A Strouhal number may be used to calculate the flow speed using extension surface diameter and detected vortex shedding frequency. Several extensions may cover a range of frequencies and flow speeds. Pipe-organ-type flowmeters include a passage with an opening constricted, and subsequent widening section. An extension and outlet that create turbulence in the flow at the outlet create a standing wave and vibration in the extension and/or entire flowmeter. A flow rale of the fluid through the flowmeter can he calculated using length of the passage and/or known properties of the fluid. Multiple, flowmeters of customized physical properties and types are useable together.