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URI permanente para esta coleçãohttps://repositorio.fei.edu.br/handle/FEI/5123
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Artigo de evento 1 Citação(ões) na Scopus A novel scroll expander for flank leakage investigation: preliminary tests(2016-07-19) FANTI, G. R.; Gustavo Donato; Paulo de Mello© 2016 University of Ljubljana.The isentropic efficiency of the expander is a concern for organic Rankine cycle (ORC) and compressed air energy storage (CAES) implementation. In these applications, the expander alone has a great influence over the whole system efficiency. Scroll expanders are particularly interesting for the low power range comprehended between 1 and 10 kW. Many previous works have attributed to internal leakages a great importance to obtain high isentropic efficiency in these machines. We present herein experimental results obtained with a novel scroll expander constructed to investigate the effect of internal leakages. We discuss the geometry definition and design of the prototype in detail. The maximum mechanical power produced by the prototype was 923 W at 2690 rpm but its isentropic efficiency was only 30.6%. Filling factor as high as 4.9 reveals that internal leakage must be reduced to obtain a more efficient expander.Artigo de evento 0 Citação(ões) na Scopus CFD simulation of scroll expanders: Influence of pressure ratio and flank clearance over the performance(2019-06-23) OLIVEIRA, F. V.; SILVA, F. M. F.; Paulo de Mello© ECOS 2019 - Proceedings of the 32nd International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems. All rights reserved.Scroll expanders are considered ideal for low power applications, in particular in small scale ORC (organic Rankine cycle). Internal leakages decrease considerably the isentropic efficiency of scroll expanders and consist the main source of inefficiency. In this paper, the performance of one scroll expander working with air for which experimental data is available is simulated. The influence of pressure ratio and tangential clearance over the results is investigated. Transient 2D CFD (computational fluid dynamics) simulations of the compressible flow capable of quantifying the internal leakages present in this machine were performed. The filling factor, generated power and isentropic efficiency were obtained and compared with experimental results from our research group. The results obtained reveal that the pressure ratio variation does not change the filling factor, thereby the internal leakages remain practically constants with the inlet pressure increase. The pressure ratio value for which the highest isentropic efficiency is obtained tends to reduce when increasing the internal leakages. The CFD simulations have shown generated power 11% higher if compared with experimental results. This difference can be attributed to uncertainty in tangential clearance measurements, radial leakage and pressure drop at expander inlet not considered in the 2D simulations.