A LIFT-FORCE FLOW SENSOR DESIGNED FOR ACCELERATION INSENSITIVITY

A silicon gas-flow sensor based on lift force is described. The sensin g structure is made of two equal plates arranged to be deflected by th e lift force. The deflection is detected with polysilicon piezoresisto rs connected in a Wheatstone bridge configuration. Due to its symmetri c design, the sensor suppresses artifacts caused by acceleration force s. Here this ability is verified both theoretically and experimentally . A flow sensitivity of 0.054 mu V/V/(l/min)(2) has been measured. Due to the lift-force sensor design, the sensitivity is independent of th e flow direction and the induced pressure drop is relatively low. The pressure drop and the flow sensitivity normalized to the pressure drop have been studied as functions of the flow attack angle. (C) 1998 Els evier Science S.A. All rights reserved.