Callaghan Innovation Research Papers

Back to Research Papers

TitleDamping and gas viscosity measurements using a microstructure
Publication TypeJournal Article
Year of Publication1995
AuthorsAndrews, M.K., and Harris P.D.
JournalSensors and Actuators: A. Physical
Pagination103 - 108
Date Published1995
ISSN09244247 (ISSN)
KeywordsAccuracy, Chemical sensors, Damping, Flow conditions, Inverse Knudsen number, Microstructure, Momentum transfer function, Oscillations, Phase technique, Pipe flow, Pipe flow correction, Plates (structural components), Transfer functions, Viscosity measurement, Viscosity of gases, Viscous flow
AbstractThe equations for squeeze-film damping of a microstructure comprising two plates oscillating normal to each other are used to derive the damping, and hence the viscosity, of six different gases under flow conditions ranging from molecular to almost viscous flow. For all the gases, the effective viscosity, normalized to the free gas viscosity, for flow in the gap between the plates is the same function of pressure when this is expressed as the inverse Knudsen number. The function is identifical in form to Knudsen's pipe-flow correction, but requires a scale change that effectively defines an equivalent diameter for parallel plates. Relative viscosity measurements are made with an accuracy of 1% by the phase technique used, and with a time resolution of 1 s. The possibility of a gas sensor based on the method is discussed. © 1995.

Back to top