超音波を利用した水素センシング：ガス濃度の絶対測定および非接触計測

抄録

Hydrogen gas concentration sensing using ultrasonic was developed and demonstrated. It uses the difference in sound velocity between hydrogen and other mixed gases such as air. Hydrogen concentration can be calculated from the sound velocity alteration measurement after hydrogen is mixed with air or other known gases. The sensor using ultrasonic is very fast in response time and low cost with a smaller size equipment. The response time of measuring gas concentration was less than 0.1 sec. It was demonstrated that it is possible to measure absolute hydrogen concentration accurately from 100 ppm to 100% with one sensor head. The ultrasonic sensor head probes distance can be as small as 20 mm. Concentration of hydrogen gas flowing inside a pipe can be also measured by using ultrasound from exterior of the pipe without extracting the gas from the pipe. Drilling a hole in the pipe is not necessary for the gas concentration measurement. Various gas flow rate was tried and it was estimated that it is possible to measure the hydrogen gas concentration in the flow rate of more than 50 m/sec.