An ethanol concentration detection method based on capacitive micromachined ultrasonic transducer

Abstract

This paper presents a method for ethanol concentration detection based on capacitive micromachined ultrasonic transducer (CMUT). The system utilizes a pair of CMUT transducers to transmit and receive ultrasonic signals, while a TR6601 temperature sensor continuously monitors the temperature of the solution under test. The acquired electrical signals undergo successive processing steps, including ultrasonic time-of-flight (TOF) measurement, ultrasonic velocity calculation, and temperature compensation. This paper analyzes the ultrasonic velocity of ethanol solutions with varying concentrations and establishes a concentration measurement model based on sound velocity and solution temperature, with the test results presented in the application. The study conducted alcohol concentration tests on four different types of aromatic Chinese spirits, and the final results demonstrates excellent accuracy in determining the volume concentration of ethanol in Baijiu, with a measurement range of 30–70 % and an error precision of 0.2 %. It exhibits stable testing performance and high sensitivity. The concentration measurement of Baijiu samples achieves sufficient accuracy. Furthermore, due to the compact size of the designed CMUT sensor, the ethanol concentration measurement system proposed can take on the role of a highly portable measurement probe for ethanol concentration detection in the Baijiu production and sales processes.