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December 4, 2006 Yang co-authors paper featured in the Journal of Micromechanics and Microengineering
Professor E H Yang, Associate Professor in the Department of Mechanical Engineering at Stevens Institute of Technology, has co-authored and published the paper Modeling of frictional gas flow effects in a piezoelectrically actuated low leak-rate microvalve under high-pressure conditions in the Institute of Physics (IOP) Publishing Journal, Journal of Micromechanics and Microengineering.
This paper discusses how a one-dimensional modeling of steady frictional radial flow of a perfect gas through a high-pressure piezoelectrically actuated microvalve under low leak-rate conditions is studied. Focusing on the micro-scale gap between the boss and seat plates, a model was developed for axisymmetric flow between two thermally insulated, parallel disks flowing radically toward an outlet hole at the center of the bottom disk. The fourth-order Runge-Kutta algorithm was utilized to integrate a system of nonlinear ordinary differential equations that govern the variations of flow properties. The most notable observation is that of a drastic increase in density and static pressure in contrast to a rather small increase in the Mach number (or velocity). The total pressure drop was also shown to be significant across the seat rings. A 2D Stokes flow model was also derived for incompressible, axisymmetric, radial flow between two concentric parallel disks in order to verify the trends of the flow property variations from the compressible radial flow model. The Stokes flow model trends for both static and total pressure concurred with the predictions of the radial compressible flow model. In addition, a comparison of Stokes flow values for both the static pressure rise and the total pressure drop to that of the numerical results demonstrates the necessity of accounting for compressibility effects.
The paper appears in the current online edition and can be viewed here. It will also be featured in the December 2006 print version of JMM.