1996 Volume 32 Issue 1 Pages 1-7
This paper deals with the effect of the added mass due to the fluid on the natural frequency of compact transducers for low pressure measurements. An approximate model of pressure transducers is presented by the radiation impedance of a piston, the piston model of a measuring diaphragm (second order system), and the cavity impedance.
On the basis of this model, it is shown that the natural frequency of fluid-loaded pressure transducers, fF, can be expressed by the added mass due to the fluid, and the spring constant kP and equivalent mass mP of the diaphragm. The values kP and mP are estimated by two ways. One is from the natural frequency of a transducer in the atmosphere, fA, or the natural frequency of a water-loaded transducer, fW, the other is from fA and fW. The fF is evaluated by experiments for several kinds of liquid. The result obtained from fA or fW is fairly good, and the result obtained from fA and fW is very good.
