title: High accuracy acoustic relative humidity measurement in duct flow with air.
abstract: An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH) instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0-12 m/s with an error of ± 0.13 m/s, temperature 0-100 °C with an error of ± 0.07 °C and relative humidity 0-100% with accuracy better than 2 % RH above 50 °C. Main advantage over conventional humidity sensors is the high sensitivity at high RH at temperatures exceeding 50 °C, with accuracy increasing with increasing temperature. The sensors are non-intrusive and resist highly humid environments.
authors.affiliation: Van Schaik Innovation Handling B.V., Glaslaan 2, Building SWA 1.032, 5616 LW, Eindhoven, The Netherlands. wvschaik@humitemp.com
authors.forename: Wilhelm
authors.initials: W
authors.lastname: van Schaik
authors.forename: Mart
authors.initials: M
authors.lastname: Grooten
authors.forename: Twan
authors.initials: T
authors.lastname: Wernaart
authors.forename: Cees
authors.initials: C
authors.lastname: van der Geld
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D000388:Air; D002138:Calibration; D004867:Equipment Design; D005740:Gases / Q000032:analysis; D006813:Humidity; D015203:Reproducibility of Results; D013696:Temperature
chemical_list: D005740:Gases