Designing a device to create a metered two-phase mixture

Abstract

Foams are used in a variety of applications. It can be used as a lightweight structural component, has favorable heat transfer properties for use as an insulator, and commonly used to attenuate vibrations. Mixing a gas phase and a liquid phase requires energy input related to the surface tension of the liquid, and much higher than its thermal energy, as a large amount of bubbles must form. This thesis investigates the Tessari or two-syringe method of foam-making by attempting to scale the design from hand-operation to the use of pneumatic cylinders to accomodate more viscous fluids, or greater quantities. Based on mathematical modeling, the design can accommodate a maximum fluid viscosity exceeding 96.3 Pa-s (96,300 cps) through 1/8 NPT pipe with no restriction. A sintered metal filter was also modeled, resulting in restrictions that reduced the maximum viscosity to the order of 1 cps (10-3 Pa-s).