Method For Gas Qualitatively Detecting Based On Acoustic Relaxation Intensity

With environmental protection being more focused,monitoring gas compositions has to be developed.Thus,It's the focus of acoustic gas field about how to design effective gas composition sensor.At present,the existing gas detection methods based on acoustic relaxation information are mainly used to analyze gas components quantitatively under the condition of known gas species,and few methods that can analyze gas qualitatively are of great operational complexity,which cannot meet the real-time requirements.Therefore,it is of great significance to design a real-time and efficient qualitative blind gas detection method.Firstly,from the theoretical research,this thesis verifies the superposition of sound velocity dispersion intensity,and modifies the expression of N sound velocity dispersion intensities by 2N+1 sound velocity values ??to extend it to the full frequency range.Depending on the existing gas component detection method based on effective specific heat capacity,a gas detection method based on the rate of change of sound velocity dispersion with temperature is proposed.With only measuring the sound velocity values at fixed frequency points,this method no longer needs other parameters,such as gas density and pressure,that reduces the workload and measurement error,also improves real-time performance.In the meantime,it is proved that the relaxation absorption coefficient can also be superposed.To reconstruct the spectrum of relaxation absorption coefficient with N relaxation processes,we make use of the relaxation absorption values at 2N fixed frequency points,and the gas compositions can be identified by the rate of change of the recovered N relaxation absorption coefficients with temperature.Furthermore,in practical application,this paper proposes a theoretical design idea of ??a broad-spectrum gas sensing method based on above results.The sensing method only needs to measure 2N+1sound velocity values to detect N kinds of gas components,and has certain fault tolerance for measurement error,which simplifies the design and implementation process of gassensing technology based on acoustic relaxation theory.Compared with the existing sensor design based on background gas detection of pollution gas,the sensing method is suitable for direct qualitative detection of gas mixtures in case of unknown gas information,which is of certain progress.Simulation results show that it is equally effective to migrate the gas detection method based on sound velocity dispersion intensity to relaxation absorption coefficient.At last,this paper proves that this detection method can still work under the condition that the temperature and sound speed data have certain measurement errors,which means high reliability.All those results show that the proposed method based on acoustic relaxation intensity can be applied to common scenes,which meets the requirements of low cost and high reliability in industrial production,and provides a new idea for the design of acoustic gas detection sensors.