A Single-Reciprocating-Piston Two-Phase Thermofluidic Prime-Mover Full article
Journal |
Energy
ISSN: 0360-5442 , E-ISSN: 1873-6785 |
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Output data | Year: 2016, Volume: 104, Pages: 250-265 Pages count : 16 DOI: 10.1016/j.energy.2016.02.113 | ||||||||
Tags | Electrical analogy, Heat converter, Heat engine, Thermofluidic oscillator, Two-phase, Unsteady | ||||||||
Authors |
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Affiliations |
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Funding (2)
1 | Skolkovo Foundation | 64 от 02.07.2012г. |
2 | Engineering and Physical Sciences Research Council | EP/J006041/1 |
Abstract:
We explore theoretically a thermodynamic heat-engine concept that has the potential of attaining a high efficiency and power density relative to competing solutions, while having a simple construction with few moving parts and dynamic seals, allowing low capital and operating costs, and long lifetimes. Specifically, an unsteady heat-engine device within which a working fluid undergoes a power cycle featuring phase-change, termed the ‘Evaporative Reciprocating-Piston Engine’ (EPRE) is considered as a potential prime mover for use in combined heat and power (CHP) applications. Based on thermal/fluid-electrical analogies, a theoretical ERPE device is conceptualized initially in the electrical-analogy domain as a linearized, closed-loop active electronic circuit model. The circuit-model representation is designed to potentially exhibit high efficiencies compared to similar, existing two-phase unsteady heat engines. From the simplified circuit model in the electrical domain, and using the thermal/fluid-electrical analogies, one possible configuration of a corresponding physical ERPE device is derived, based on an early prototype of a device currently under development that exhibits some similarities with the ERPE, and used as a physical manifestation of the proposed concept. The corresponding physical ERPE device relies on the alternating phase change of a suitable working-fluid (here, water) to drive a reciprocating displacement of a single vertical piston and to produce sustained oscillations of thermodynamic properties within an enclosed space. Four performance indicators are considered: the operational frequency, the power output, the exergy efficiency, and the heat input/temperature difference imposed externally on the device's heat exchangers that is necessary to sustain oscillations. The effects of liquid inertia, viscous drag, hydrostatic pressure, vapour compressibility and two-phase heat transfer in the various engine components/compartments are examined, via changes to thermodynamic/thermophysical/transport properties and also geometrical features of the ERPE. It is found that for high efficiency and power output: (1) the vapour dead-spaces must be minimized; (2) the length of the tube that connects the displacer and working cylinders must be of significant length; and, (3) the heat-exchanger blocks must have a low thermal resistance and high heat capacity. The methodological approach implemented in this study can be used to guide the proposal, early-stage design and verification of these complex unsteady thermodynamic systems, while offering important suggestions for improved performance and system optimization.
Cite:
Taleb A.I.
, Timmer M.A.G.
, El-Shazly M.Y.
, Samoilov A.
, Kirillov V.A.
, Markides C.N.
A Single-Reciprocating-Piston Two-Phase Thermofluidic Prime-Mover
Energy. 2016. V.104. P.250-265. DOI: 10.1016/j.energy.2016.02.113 WOS Scopus РИНЦ
A Single-Reciprocating-Piston Two-Phase Thermofluidic Prime-Mover
Energy. 2016. V.104. P.250-265. DOI: 10.1016/j.energy.2016.02.113 WOS Scopus РИНЦ
Files:
Full text from publisher
Dates:
Submitted: | Oct 25, 2015 |
Accepted: | Feb 18, 2016 |
Published online: | Apr 22, 2016 |
Published print: | Jun 1, 2016 |
Identifiers:
Web of science | WOS:000377727000022 |
Scopus | 2-s2.0-84963831116 |
Elibrary | 27010423 |
OpenAlex | W2338100857 |