Technical PapersThe following technical papers describe the proprietary technologies and analysis methods that support the ultra-high efficiency and performance of the Wilson Heat Exchanger™ and Wilson Microturbine™. Each complete paper is available for review or download. |
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Design and Performance of a High-Temperature Regenerator Having Very High Effectiveness, Low Leakage and Negligible Seal WearASME Turbo-Expo 2006 Abstract. A high-temperature regenerator has been designed under MIT and WTP patents. This regenerator was designed to be compatible with a high-temperature 5 kW solid-oxide fuel cell. Our design studies indicate that, when applied (in a considerably larger size) to microturbines, it would enable electrical efficiencies of 50% to be exceeded. Other industrial applications that require too high a temperature for currently available recuperators would also become viable. The paper describes design methods that are substantially different from those in general use and discusses design choices for materials and actuation systems. In operation, the ceramic-honeycomb regenerator disk rotates incrementally, in this case through 90 degrees for each movement. The seals, which can conform to the profile of the sealing surface, are firmly pressed to the regenerator seal faces during the stationary periods, here about fourteen seconds. The seals then lift marginally, just enough to allow free disk movement, during the 0.75 second of the indexing period. Thus no sliding wear can take place. In the demonstrator unit tested, the measured effectiveness was over 98%, the pressure drops of the hot and cold flows were under 2%, and the leakage was low within experimental error. The demonstrator was tested at a top temperature of 910°C. (The final temperature after development should be well above 1000°C.) |
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Regenerative Heat Exchangers for Microturbines, and an Improved TypeASME Turbo-Expo 2003 Abstract. The principle of operation of regenerative heat exchangers (“regenerators”) is explained, and the characteristics are compared with those of recuperators. The design rules for heat exchangers in general are stated, and the particular design rules for regenerators are discussed in more detail. Problems in past regenerators have led to an improved type, which is described. Design studies of a regenerator for a typical microturbine at three different levels of effectiveness are given, and leakage rates estimated. At the highest regenerator effectiveness, and using the improved compressor and turbine design permitted by this effectiveness, it is estimated that a 300 kW microturbine should achieve 50% electrical efficiency. |
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The Basis for the Prediction of High Thermal Efficiency in Wilson TurboPower Gas-Turbine EnginesDavid Gordon Wilson Summary. A high thermal efficiency for an engine requires that a cycle capable of producing high efficiency is first chosen, and that components that can operate at high efficiencies are used. The choices made in both areas are discussed below. The “enabling” technology is a high-temperature, high-effectiveness (0.975) regenerator, with a low pressure drop. This requires only a low cycle pressure ratio (about 2.5:1) for optimum performance. The component efficiencies of compressors and turbines of low pressure ratio are intrinsically high. WTP also divides this low pressure ratio among three compressor stages and three turbine stages. Doing so greatly reduces the component efficiencies. By these means a shaft-power efficiency of 54% can be confidently predicted for the 300 kW engine, which when coupled to a high-efficiency electrical generator would lead to an electrical efficiency of about 50%. |
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