Nonlinear Acoustic Resonance Spectrometry for Void Rate Measurement
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Solution Overview
Problem
Current methods fail to accurately determine the void rate in opaque media like liquid sodium in nuclear reactors, which is crucial for monitoring and preventing gas pocket formation, due to the limitations of optical and linear acoustic techniques in such environments.
Innovation Solution
The method employs Nonlinear Resonant Ultrasound Spectroscopy (NRUS) using a bulk elastic wave resonator to measure frequency shifts in acoustic waves, allowing for the determination of void rate by scanning frequencies and amplitudes, and calculating the slope of resonance curves to quantify the nonlinearity caused by gas bubbles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical techniques are used to determine void rate, then measurement precision is improved in transparent media, but the method becomes inapplicable in opaque media like liquid sodium
Solution Approach 1:
The patent replaces optical measurement techniques with acoustic techniques. Instead of using light propagation methods that fail in opaque media, the invention employs acoustic wave propagation and resonance methods that can effectively penetrate and measure void rates in opaque liquids like liquid sodium, thus substituting one physical domain (optics) with another (acoustics) better suited for the measurement environment
Solution Approach 2:
The patent changes the measurement parameter from optical properties (light transmission, refraction) to acoustic properties (sound wave propagation, resonance frequency, attenuation). By measuring acoustic parameters such as the resonance frequency shift and attenuation coefficient of sound waves in the liquid sodium, the system can determine void rate without being affected by the optical opacity of the medium
2Adaptability or versatility
If linear acoustic techniques are used to determine void rate, then the method can be applied in opaque media, but measurement precision deteriorates due to ambiguities
Solution Approach 1:
The patent employs resonance vibration of acoustic waves at specific frequencies. By exciting the liquid sodium with acoustic waves at resonant frequencies and measuring the resonance characteristics (frequency shift, attenuation), the system obtains enhanced measurement precision. The resonant vibration amplifies the interaction between acoustic waves and gas bubbles, making the void rate measurement more sensitive and accurate compared to linear acoustic techniques
Solution Approach 2:
The patent converts the harmful effect of gas bubbles (which cause scattering and attenuation of acoustic waves, creating measurement ambiguities) into a beneficial effect. By measuring the resonance frequency shift and attenuation caused by bubble scattering, the system directly quantifies the void rate. The scattering that initially creates measurement difficulties becomes the very mechanism used to detect and measure the gas bubble concentration
3Extent of automation
If acoustic waves are used for monitoring, then continuous monitoring capability is improved, but accurate interpretation of measurements requires knowledge of attenuation coefficients which are difficult to determine
Solution Approach 1:
The patent implements a feedback mechanism where the resonance characteristics measured from the liquid sodium are used to directly determine the void rate. The system continuously monitors acoustic resonance parameters, feeds this information back to calculate void rate in real-time, and provides continuous monitoring output. This eliminates the need for separate attenuation coefficient measurements because the resonance measurements themselves contain all necessary information for void rate determination
Solution Approach 2:
The patent creates a multi-functional acoustic measurement system that simultaneously performs multiple functions: it measures resonance frequency to determine void rate, measures attenuation to characterize bubble distribution, and provides continuous monitoring capability. This universal system eliminates the need for separate measurement devices and complex data integration, as a single acoustic resonance measurement provides multiple pieces of information about the liquid sodium's void rate and bubble characteristics
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
This approach provides accurate void rate measurements in biphase gas/liquid media, avoiding ambiguities and enabling continuous monitoring of gas pockets, thus enhancing reactor safety and operational control.
Implementation Method 1
measurement by nonlinear resonant ultrasound spectroscopy of the biphase medium comprising the scanning in terms of frequencies and amplitudes of acoustic excitation in a given range of frequencies and in a given range of amplitudes, of bulk elastic waves emitted and detected at said resonator
Implementation Method 2
the determination of the void rate on the basis of said slope... leading to the obtaining of a set of resonance curves exhibiting maxima
Data Source
AI summary
A method of determining the void rate in a biphase gas/liquid medium, corresponding to the volume fraction of gas corresponding to the presence of bubbles in the liquid medium in a total volume of gas and liquid, comprises: deployment of a bulk elastic wave resonator in contact and coupled acoustically with the biphase medium; measurement by nonlinear resonant ultrasound spectroscopy of the biphase medium comprising the scanning in terms of frequencies and amplitudes in a given range of frequencies and in a given range of amplitudes, of bulk elastic waves emitted and detected at said resonator placed in said medium and leading a set of resonance curves exhibiting maxima; determination of a straight line defined by the set of maxima of said curves and of the slope of said straight line; determination of the void rate on the basis of said slope. The method may be applied to a nuclear reactor.