A simple mathematical analog for determination of the squeeze film behavior between two parallel annular disks, one having a porous facing, from the already available solutions of comparable nonporous disks is presented. A comparison of the analog solution with a Fourier-Bessel solution has been made and the agreement is found to be good for a range of values of the permeability parameter and the porous facing thickness. The results also have been extended to include the rotating inertia effect of the film fluid. The resulting dimensionless pressure distribution and the dimensionless squeeze film load are expressed in terms of a permeability parameter, inertia parameter, squeeze film number, and the disk dimensions. For constant squeeze film load, a relationship between squeeze time and film thickness also has been obtained. Generally, the presence of the porous facing will decrease the squeeze film load and will reduce the total squeeze time to some finite value. The inertia effect will further decrease the squeeze film load and the squeeze time, however, the squeeze time reduction due to the inertia effect will become small if the porous facing has high permeability and is thick.
An ER Microactuator with Built-in Pump and Valve
