High Temperature, High-Pressure Fluid Connections for Power Micro-Systems

摘要

High power density micro-systems offer the potential to revolutionize technologies for portable electrical power generation, propulsion and flow control. Devices are being designed and fabricated which include micro-gas turbine engines, micro-rocket engines, micro-motor-compressors, micro-pumps and micro-hydraulic transducers. Common to all of this family of devices is the need to create packages that service the devices, and interface them with the macro-scale environment. Fluid interconnections are a particularly demanding packaging element for this class of devices. In order to achieve high power densities, these devices are required to operate at high pressures and, in some cases, high temperatures. This paper describes the design, analysis, fabrication and testing of high-pressure, high temperature fluid connections for the micro-engine and micro-rocket applications. A glass bonding technology has been developed to allow the creation of multiple fluidic connections consisting of Ni/Fe alloy tubes to silicon devices. Key strategies to achieve high strength connections arc: to minimize the mismatch in coefficients of thermal expansion between the components, to eliminate voids from the glass and to promote adequate wetting of the glass to both the tubes and the silicon. Mechanical test results are presented which correlate the strength and statistical reliability of such bonds to the processing conditions, choice of glass and surface preparation prior to bonding. Successful examples of packaged micro-engine and micro-rocket devices are presented.