Two-dimensional delay line SAW based Hydrogen gas sensor for leakage detection in pipelines using Palladium nano particles

The world is witnessing a transformative shift towards sustainable energy solutions, and hydrogen gas has emerged as a promising clean energy carrier with the potential to revolutionize our energy landscape. As hydrogen pipelines become an integral part of the infrastructure supporting this green energy transition, ensuring their safety and reliability becomes paramount. Among the critical challenges faced by hydrogen pipeline operators, one of the most pressing is the detection of gas leakage. Detecting hydrogen gas leaks in pipelines is not only essential for maintaining the integrity of the infrastructure but also for preventing potential safety hazards and minimizing environmental impacts. This paper presents a design to detect such leakages using two-dimensional delay line SAW based hydrogen gas sensor using COMSOL Multiphysics. The sensor is constructed with langasite piezoelectric substrate, IDT is built with aluminium and ZnO is used for sensing layer. To enhance the sensitivity of the device palladium nano particles are added to the sensor with extra conductive layer placed in the sensing layer. The proposed sensor is analysed for surface deflection, electric potential with as well as without hydrogen gas by varying the width of conductive layer from 1000μm to 3000μm.In addition to this, sensor is also tested for hydrogen environment with the concentration of gas ranging from 10ppm to 100ppm and sensitivity of the sensor is analysed. The simulated results relieved that the deflection of the sensor decreases with hydrogen gas and surface electric potential increases at all the widths of conductive layer. The conductive layer with width of 3000 μm achieved maximum deflection, electric potential and high sensitivity due to amplification provided by the conductive layer and nano particles. With hydrogen gas the sensor experiences a positive frequency shift due to change in electro acoustic effect on the sensing layer. But the sensor exhibits linearity with deflection and frequency with rise in the concentration of hydrogen gas. Further an electric equivalent model of the SAW sensor is designed using Colpitts oscillator to generate the operating frequency of SAW sensor. Electronic equivalent model is simulated using NI Multisim. The device has shown close approximation of theoretical frequency, simulated frequencies.