A Self-Resonant, Mems-Fabricated, Air-Breathing Engine

Herrault, Florian; Crittenden, Thomas; Yorish, S.; Birdsell, Edward D.; Glezer, Ari; Allen, Mark G.

doi:10.31438/trf.hh2008.90

Cited by 4 publications

(1 citation statement)

References 9 publications

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“…Development of micro-scale heat engines based on the Rankine cycle [1], Otto cycle [2], Brayton cycle [3], Stirling cycle [4], and Humphrey cycle [5] has been proposed by different research groups. Our group has developed a resonant micro-scale dynamic heat engine that is not based on these standard cycles.…”

Section: Introductionmentioning

confidence: 99%

On the Thermodynamic Cycle of a MEMS-Based External Combustion Resonant Engine

Bardaweel

Richards

et al. 2010

Volume 5: Energy Systems Analysis, Thermodynamics and Sustainability; NanoEngineering for Energy; Engineering to Address Climat

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In this work we investigate the thermodynamic cycle of a resonant, MEMS-based, micro heat engine. The micro heat engine is made of a cavity encapsulated between two membranes. The cavity is filled with saturated liquid-vapor mixture working fluid. Heat is added/rejected from the engine at a frequency equal to its resonant frequency. Both pressure-volume and temperature-entropy diagrams of the resonant engine are used to investigate the thermodynamic cycle of the resonant micro heat engine. The results show that the thermodynamic cycle of the engine consists of four major processes: heat addition, expansion, heat rejection, and compression. pressure-volume and temperature-entropy diagrams are bounded by two constant temperature processes and two constant volume processes. The temperature-entropy and pressure-volume diagrams show deviations from this ideal description and are rounded due to the presence of irreversible effects. Major sources of irreversibility in the engine are heat transfer over finite temperature differences during heat addition and rejection, heat transfer into and out of engine thermal mass and viscous losses due to liquid working fluid motion. The measured second law efficiency of the micro heat engine is about 16%.

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Section: Introductionmentioning

confidence: 99%

On the Thermodynamic Cycle of a MEMS-Based External Combustion Resonant Engine

Bardaweel

Richards

et al. 2010

Volume 5: Energy Systems Analysis, Thermodynamics and Sustainability; NanoEngineering for Energy; Engineering to Address Climat

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MEMS-based resonant heat engine: scaling analysis

et al. 2011

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In this article, a scaling model of a MEMSbased resonant heat engine is presented. The engine is an external combustion engine made of a cavity encapsulated between two thin membranes. The cavity is filled with a saturated liquid-vapor mixture working fluid. Both model and experiment are used to investigate issues related to scaling of the engine. The results of the scaling analysis suggest that the performance of the engine is determined by three major factors: geometry of the engine, speed of operation, and thermal-physical properties of engine components. Larger engine volumes, working fluids with higher latent evaporation property, slower engine speeds, and compliant expander structure are desirable. In experiments, the expander membrane material and thickness, and the thickness of engine cavity are varied. The experimental measurements show that the velocity amplitude of the expander membrane increases by approximately a factor of 20 when more compliant structure with less thermal inertia is used.

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Characterization of the thermodynamic cycle of a MEMS-based external combustion resonant engine

Bardaweel

Richards

et al. 2012

Microsyst Technol

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The thermodynamic cycle of a resonant, MEMS-based, micro heat engine is characterized. The micro heat engine is an external combustion engine made of a cavity encapsulated between two membranes. The cavity is filled with saturated liquid-vapor mixture working fluid. Heat is added to and rejected from the engine at a frequency corresponding to the resonant frequency of the engine. Both pressure-volume and temperature-entropy diagrams are used to investigate the thermodynamic cycle of the resonant micro heat engine. The results show that the working cycle is nearly rectangular in shape and consists of two constant temperature processes and two constant volume processes. We hypothesize that major sources of irreversibility in the engine are heat transfer over finite temperature differences during heat addition and rejection, heat transfer into and out of engine thermal mass, viscous losses due to liquid working fluid motion, and heat escape from the engine to the surroundings. The maximum pressure and volume changes measured inside the engine cavity are 45 Pa and 0.55 mm 3 , respectively. The results show that for a heat addition of 1 mJ, the engine operates over a very small temperature difference. The small operating temperature difference is mostly attributable to the large thermal storage of the engine structure, the membranes and the wicks. The measured second law efficiency of the micro heat engine is 16 %.

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A Self-Resonant, Mems-Fabricated, Air-Breathing Engine

Cited by 4 publications

References 9 publications

On the Thermodynamic Cycle of a MEMS-Based External Combustion Resonant Engine

On the Thermodynamic Cycle of a MEMS-Based External Combustion Resonant Engine

MEMS-based resonant heat engine: scaling analysis

Characterization of the thermodynamic cycle of a MEMS-based external combustion resonant engine

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