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1 edition of Investigation of a heat driven thermoacoustic prime mover above onset of self-oscillation found in the catalog.

Investigation of a heat driven thermoacoustic prime mover above onset of self-oscillation

Earl Clayton Bowers

Investigation of a heat driven thermoacoustic prime mover above onset of self-oscillation

by Earl Clayton Bowers

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Published by Naval Postgraduate School, Available from the National Technical Information Service in Monterey, Calif, Springfield, Va .
Written in English


Edition Notes

ContributionsAtchley, Anthony Armstrong, 1957-
The Physical Object
Pagination56 p. ;
Number of Pages56
ID Numbers
Open LibraryOL25454410M

  The present research shows that the magnitude and position of the maximum cooling temperature depend on the position of the prime mover stack from the nearest pressure antinode. Based on the design of this simplified thermally driven thermoacoustic refrigerator, the design of a complete thermally driven thermoacoustic refrigerator is in progress. The construction of a thermoacoustically (heat) driven, thermoacoustic refrigerator (TADTAR) is nearing completion. The design utilizes a novel resonator topology and high‐efficiency primary heat exchangers. Numerical models suggest a cooling power level of at least W over a temperature span of 40 °C. The design should be easily scalable to much higher cooling power levels.

The transition to onset in a prime mover is conveniently discussed in terms of its Q. The acoustic power W generated by a prime mover can be related to Q through the relationship O)E.(1) wES A typical prime mover is comprised of five sections: the ambient duct, the ambient heat exchanger, the prime mover stack, the hot heat exchanger, and the. Steady-flow heat transfer correlations to design a heat exchanger are not suitable for the thermoacoustic refrigerators due to their oscillatory flow conditions in resonator tubes. In this paper, a heat transfer correlation for a spiral-coil heat exchanger is presented.

THERMOACOUSTIC HEAT ENGINE 71 with K being the thermal conductivity, ρm, the mean density, cp, the constant pressure specific heat, and ω, the circular frequency of the working fluid. A thick boundary layer encourages heat transfer by conduction during a period of 1/ ω, where ω is the circular frequency of the vibrating fluid. thermoacoustic heat pumping-is far less well known, and was the first intentional demonstration of a new class of in- trinsically irreversible heat engines. Traditional heat engine cycles, such as the Carnot cycle typically studied in elementary thermodynamics courses, as- sume that the individual steps in the cycle can be made re- versibly.


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Investigation of a heat driven thermoacoustic prime mover above onset of self-oscillation by Earl Clayton Bowers Download PDF EPUB FB2

Calhoun: The NPS Institutional Archive Theses and Dissertations Thesis Collection Investigation of a heat driven thermoacoustic prime mover above onset of self-oscillation.

The goal of this thesis is to investigate the work output of a heat driven thermoacoustic prime mover above onset of self-oscillation. The exponentially growing sound wave, generated when a prime mover is initially 'turned on,' was digitally sampled for a helium filled prime mover at pressures ranging from kPa to kPa and at temperature differences ranging from onset to by: 2.

Investigation of a heat driven thermoacoustic prime mover above onset of self-oscillation. By Earl Clayton Bowers. Download PDF (3 MB) Abstract. Approved for public release; distribution is unlimitedThe goal of this thesis is to investigate the work output of a heat riven thermoacoustic prime mover above onset of self-oscillation.

Author: Earl Clayton Bowers. Investigation of a Heat Driven Thermoacoustic Prime Mover above Onset of Self-Oscillation by Earl Clayton Bowers Lieutenant, United States Navy B.S., United States Naval Academy, Submitted in partial fulfillment of the requirements for the degrees of MASTER OF SCIENCE IN APPLIED SCIENCE, and MASTER OF SCIENCE IN ENGINEERING ACOUSTICS from theCited by: 2.

The onset temperature difference of a thermoacoustic Stirling prime mover deeply depends on the length and porosity of the regenerator, the working gas, the frequency and the pressure, this.

The model in the present work simulates the free oscillation in the thermoacoustic engine driven by the heat above onset temperature.

The working fluid is the helium of 2 MPa. The thermoacoustic heat engines was proposed as a solution to the heat transfer problem in microcircuits, pumping heat or producing spot cooling of specific circuit elements, i.e., a thermoacoustic prime mover converts heat to acoustic energy, or a thermoacoustic cooler or heat pump uses sound to pump heat upon a temperature gradient, as shown.

The frequency response of a thermoacoustic prime mover has been measured as a function of the mean gas pressure and temperature gradient across the prime mover stack. The quality factor Q and resonance frequency can be determined from the response.

As the temperature gradient is increased, the Q increases, indicating a decrease in attenuation across the stack. The heat energy of heater converts to acoustic power accompany with the heater temperature decreases and the cooler temperature increases when the prime mover onset.

It can be seen from Fig. 7 that the temperature rise of 90° tilted angle is more obvious than that of 0° tilted angle when the prime mover onset. This is due to the onset. Fig. 1 shows the physical model and simulation domain for the thermoacoustic prime mover with half wavelength, which is composed of the prime mover and a resonant tube.

The part of prime mover includes a parallel-plate stack, a hot-end heat exchanger and a cold-end heat exchanger. In this system, the stacks contain many identical parallel plates and it is ratio of the gap width and tube.

Book Search tips Selecting this option will search all publications across the Scitation platform Selecting this option will search all publications for the Publisher/Society in context.

“ A thermoacoustic Stirling heat engine,” Nature “ Analysis of a thermoacoustic prime mover above onset of self-oscillation,” J. Acoust. Soc. Earl C. Bowers, "Investigation of a heat driven thermoacoustic prime mover above the onset of self-oscillation," Master's Thesis, Naval Postgraduate School, September H.

Lin, "Investigation of a Heat Driven Thermoacoustic Prime Mover," Master's Thesis, Naval Postgraduate School, December   Arnott computed the onset temperature and the resonance frequency for a standing wave thermoacoustic prime mover and demonstrated that the self-oscillation took place when the acoustic power produced in the stack was greater than the viscous and thermal losses in the system.

All of the above researchers assumed that the onset point coincided. Standing wave analysis of a thermoacoustic prime mover belo w onset of self- oscillation.

Journal of the Acoustical Society of America, 92(5)–, In this review, an introduction of the thermoacoustic effect is supported by a summary of related theoretical models for thermoacoustics. An overview of the current research and experimental prototypes including typical thermoacoustic prime movers, thermoacoustic refrigerators, thermoacoustically driven pulse tube refrigerators, thermoacoustic.

A thermoacoustic prime mover is a heat engine which converts thermal energy to sound. The stack material is sandwiched between the hot and cold heat exchanger and exchanges heat with the cycling. the heat above onset tempera ture.

e working uid is prime mover below onset of self-oscillation. efficiency of the low-grade heat driven thermoacoustic engine systems. The model in the present work simulates the free oscillation in the thermoacoustic engine driven by the heat above onset temperature.

The working fluid is the helium of 2 MPa. The pressure ratios at the position of P1 in four systems were all set at The onset and damping processes of self-excited working-fluid oscillation in thermoacoustic prime movers, related to the quality of the utilizable thermal energy, have attracted everlasting.

In this paper the various investigations in thermoacoustic refrigeration system are reviewed. Thermo acoustic refrigerator is a new type of energy conversion device, which can convert acoustic power into heat energy based on the thermo acoustic effect.

Thermoacoustic refrigeration is an emerging refrigeration technology which does not require any moving parts or any environmentally. This article introduces a heat-driven thermoacoustic cooler capable of reaching liquid nitrogen temperature with no moving parts. The thermoacoustic cooler consists of a traveling wave thermoacoustic prime mover and a pulse tube cooler.

By using a tapered resonance tube, the prime mover can provide a pressure ratio higher than By using a long thin tube, a reservoir is no .Thermoacoustic engines are the devices that convert thermal energy into acoustic energy without moving parts.

The main objective of this study is to analyze the performance of a thermoacoustic prime mover measured in terms of onset temperature difference, frequency, and pressure amplitude by varying resonator, stack length, and plate thickness.In the yearB.

Yu et al. experimentally studied, travelling wave thermoacoustic refrigeration driven by thermoacoustic prime mover, with single prime mover system the operating frequency of 57 Hz and 3 Mpa pressure could be achieved. InBharatbhushan V .