Designing a miniaturized photoacoustic sensor for detecting hydrogen gas

In this paper, photoacoustic spectroscopy method is used for hydrogen gas detection. In order to improve the performance of the sensor, we have used a miniaturized dumbbell-shaped cell containing two buffer volumes and a resonator. The coupled photoacoustic equations have been solved in gaseous environment using finite-element-method and by corresponding validation. The impacts of various effective parameters such as frequency response, quality factor, acoustic pressure and heat have been analyzed. Frequency analysis in the hydrogen gas medium leads to the first natural frequency of the sensor at 88.563 kHz which has 65 kHz difference with the second natural frequency. By studying the behavior of the resonance frequencies of the proposed system, the optimum location for the sensor positioning of the designed system has been investigated for different gases and the results show that the designed photoacoustic sensor has the fingerprint feature for detecting hydrogen gas. Moreover, the results of the cell filled by hydrogen gas have been compared to those obtained from other gases such as propane, nitrogen and carbon dioxide. The performance of the system is also evaluated for volatile organic compounds (VOCs) and nitrogen dioxide (NO2). The analysis of the proposed miniature system shows a significant improvement in the quality factor as well as the reduction in system losses.