Measuring Sound Speed in Gas Mixtures Using a Photoacoustic Generator

Suchenek, M.; Borowski, Tomasz

doi:10.1007/s10765-017-2335-2

Cited by 23 publications

(12 citation statements)

References 8 publications

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“…As explained earlier, the phase difference between the signals sent and received is a function of the speed of sound. This method can be used to measure the speed of sound on the length of a small path that can have a length as short as one wavelength [18].…”

Section: Methodsmentioning

confidence: 99%

“…In addition to determining the type of gas, the sound speed parameter can be used to determine gas concentration based on mathematical calculations that are proportional to the difference in sound propagation time [16], and the speed of sound can also be used to calculate the molar mass composition of a gas in a gas mixture based on thermodynamic equations [17] In this study, the parameter used as a reference for determining the concentration of CO2 in a gas mixture is the speed of sound, by utilizing phase shifts between ultrasonic wave signals that are transmitted and received continuously. The phase difference between the sent and received ultrasonic wave signals is a function of the speed of sound [18]. In the gas mixture analysis, the sound velocity information obtained makes it possible to determine the percentage of gas composition in the gas mixture [19].…”

Section: Open Accessmentioning

confidence: 99%

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Acoustic CO2 Gas Sensor Based on Phase Difference Measurement

Febrina

Satria

Djamal

et al. 2021

J. Sci. Appl. Tech.

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In this research, an acoustic sensor has been successfully built to measure the concentration of CO2 gas in a mixture of gases (N2 and CO2). The nitrogen and carbon dioxide gases used are ultra-high purity (UHP) gas. The measurement parameter used is the speed of sound by utilizing the phase shift between ultrasonic wave signals that are sent and received continuously. The acoustic method in this research is by using the speaker as an ultrasonic wave transmitter, and the microphone as an ultrasonic wave receiver emitted by the speaker on the gas medium. This acoustic phase shift method is very sensitive to be used to determine the speed of sound on a gas medium. From the sensor testing, the sensor has good linearity in detecting changes in CO2 concentration in the gas mixture. The sensor test results have been validated theoretically and obtained an RMS error of 3.36 (3.36% with a maximum concentration of 100%), this proves that the work of the sensor is in accordance with the theory. In addition to theoretical validation, the work of the sensor has also been validated by looking at the direct relationship between sensor input and output through the inverse function, and an RMS error of 3.51 (3.51% with a maximum concentration of 100%) is obtained. From the overall results obtained, the acoustic CO2 gas sensor that is built can detect changes in CO2 concentrations in the gas mixture accurately, fabrication of the sensor is easy to do, and the costs required in the manufacturing process are cheap.

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Section: Methodsmentioning

confidence: 99%

Section: Open Accessmentioning

confidence: 99%

Acoustic CO2 Gas Sensor Based on Phase Difference Measurement

Febrina

Satria

Djamal

et al. 2021

J. Sci. Appl. Tech.

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“…The sound speed of a mixture gas depends on chemical constituents and gas temperature. Then, Equation (2) will contain the sum of each gas constituent, γ i , and M i , and x i is the fraction of the i constituent [27].…”

Section: Experimental Conditionsmentioning

confidence: 99%

Potential for Shock-Wave Generation at Diesel Engine Conditions and Its Influence on Spray Characteristics

et al. 2020

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Increasing the fuel injection pressure is currently the most effective way to achieve a better fuel–air mixing quality in modern engines. Systems capable of delivering fuels at a pressure of over 250 MPa have been widely adopted in diesel engines. At such high injection pressures, the shock-wave generation during fuel injection has been noticed. Investigations can be found widely discussing on how the shock-wave generation during fuel injection would affect the spray dynamics. However, the argument remains whether the shock wave can occur at diesel engine conditions since the diesel engine is operated at very high ambient temperature and density. Even if it could occur, how significantly the spray-induced shock wave affects the spray characteristics is rarely known. To address these concerns, this study was proposed. First, experiments were conducted to obtain the detailed spray dynamics from the nozzle exit to spray downstream field by taking advantage of the X-ray phase-contrast imaging (XPCI) and schlieren imaging techniques. It is found that supersonic and subsonic ligaments coexist in one spray. Increasing the injection pressure or reducing the ambient density would extend the supersonic part in the spray. Multiple shock waves occur subsequently from the nozzle exit, where the spray has the highest local velocity. Shock-wave generation during fuel injection could enhance spray penetration, whereas this effect depends on the length of the supersonic part in the spray. Finally, a diagram was proposed to predict the potential for the shock-wave generation and discuss the possible effect on spray characteristics at diesel engine conditions.

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“…Indeed, some parameters such as the resonant frequency of a cantilever 6 , the gas sound velocity 7 and the acoustic attenuation coefficient 8 , 9 depend on the gas physical properties. This allowed the development of gas density sensors 10 and in some cases these principles can be exploited to measure a binary gas mixture concentration 11 , 12 . Some of these sensors consist of capacitive micromachined ultrasonic transducers (CMUTs) 13 .…”

Section: Introductionmentioning

confidence: 99%

Gas discrimination by simultaneous sound velocity and attenuation measurements using uncoated capacitive micromachined ultrasonic transducers

Hernandez

Shanmugam

Michaud

et al. 2022

Sci Rep

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Chemically functionalized or coated sensors are by far the most employed solution in gas sensing. However, their poor long term stability represents a concern in applications dealing with hazardous gases. Uncoated sensors are durable but their selectivity is poor or non-existent. In this study, multi-parametric discrimination is used as an alternative to selectivity for uncoated capacitive micromachined ultrasonic transducers (CMUTs). This paper shows how measuring simultaneously the attenuation coefficient and the time of flight under different nitrogen mixtures allows to identify hydrogen, carbon dioxide and methane from each other and determine their concentration along with identification of temperature and humidity drifts. Theoretical comparison and specific signal processing to deal with the issue of multiple reflections are also presented. Some potential applications are monitoring of refueling stations, vehicles and nuclear waste storage facilities.

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Measuring Sound Speed in Gas Mixtures Using a Photoacoustic Generator

Cited by 23 publications

References 8 publications

Acoustic CO2 Gas Sensor Based on Phase Difference Measurement

Acoustic CO2 Gas Sensor Based on Phase Difference Measurement

Potential for Shock-Wave Generation at Diesel Engine Conditions and Its Influence on Spray Characteristics

Gas discrimination by simultaneous sound velocity and attenuation measurements using uncoated capacitive micromachined ultrasonic transducers

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