Finite time thermodynamic analysis of small alpha-type Stirling engine in non-ideal polytropic conditions for recovery of LNG cryogenic exergy. (15th December 2017)

• Record Type: Journal Article
• Authors: Buliński, Zbigniew; Szczygieł, Ireneusz; Krysiński, Tomasz; Stanek, Wojciech; Czarnowska, Lucyna; Gładysz, Paweł; Kabaj, Adam
• Is Part Of: Energy. Volume 141(2017)
• Page Start: 2559
• Page End: 2571
• Publication Date: 2017-12-15
• Subjects: Mathematical modelling -- Alpha-type Stirling engine -- Second order analysis -- Engine performance -- Liquefied natural gas; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2017.10.026
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: In the paper, a second order thermodynamic analysis of a small scale alpha-type Stirling engine is presented. The developed mathematical model is based on the Finite Time Thermodynamics (FFT) approach and it is derived from the differential time dependent equations of energy and mass conservation. The engine model consists of three spaces: compression, expansion and regenerator. In contrast to available models, the model presented in this paper assumes polytropic processes in the compression and expansion spaces, which corresponds to the non-ideal heat transfer in these spaces. The results, obtained using the developed second order model, were compared with the results obtained using the Computational Fluid Dynamics (CFD) analysis of the same engine. A very good agreement between the second order model and the CFD model was achieved. Finally, the developed model was applied to analyse potential to recover cryogenic exergy of the Liquefied Natural Gas (LNG). The paper presents the results of the dimensional upscaling of the engine and the influence of the average working pressure. It was revealed that increasing the size of the engine or the average working pressure moves the engine to practically unachievable working conditions. Highlights: Development of the polytropic mathematical model of small alpha-type Stirling engine. Analysis of the influence of heat transfer conditions on the engine performance. Analysis of the performance of small-scale alpha-type Stirling engine to recover cryogenic exergy of Liquefied Natural Gas.