Analysis of the Exergy of Combustion the Diesel and Biodiesel Fuel in a DI Diesel Engine

Introduction In recent years, the exergy analysis method has been widely used in the design, simulation and performance assessment of various thermal systems. In this regard, this method may be applied to various types of engines for identifying losses and efficiencies. This analysis is based on the...

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Autor principal:	G Khoobbakht
Formato:	article
Lenguaje:	EN FA
Publicado:	Ferdowsi University of Mashhad 2019
Materias:	diesel biodiesel exergy response surface Agriculture (General) S1-972 Engineering (General). Civil engineering (General) TA1-2040
Acceso en línea:	https://doaj.org/article/877fec5d1c33461ea9e12216ac99392b
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id	oai:doaj.org-article:877fec5d1c33461ea9e12216ac99392b
record_format	dspace
institution	DOAJ
collection	DOAJ
language	EN FA
topic	diesel biodiesel exergy response surface Agriculture (General) S1-972 Engineering (General). Civil engineering (General) TA1-2040
spellingShingle	diesel biodiesel exergy response surface Agriculture (General) S1-972 Engineering (General). Civil engineering (General) TA1-2040 G Khoobbakht Analysis of the Exergy of Combustion the Diesel and Biodiesel Fuel in a DI Diesel Engine
description	Introduction In recent years, the exergy analysis method has been widely used in the design, simulation and performance assessment of various thermal systems. In this regard, this method may be applied to various types of engines for identifying losses and efficiencies. This analysis is based on the second law of thermodynamic. Exergy is a potential or quality of energy. It is possible to make sustainable quality assessment of energy. In this study, the second law of thermodynamics is employed to analyze the quantity and quality of exergy in a fourstroke, four-cylinder, diesel engine using diesel fuel and biodiesel fuel. Materials and Methods Four experiment variables in the present study including the operating parameters, load and speed, and the added volume of biodiesel of diesel fuel were considered as effective factors on the Break exergy efficiency. Designs that can ﬁt model must have at least three different levels in each variable. This is satisﬁed by Central Composite Rotatable Designs (CCRD). Similar to the case of the energy analysis, the same assumptions were valid for exergy analysis; the whole engine was considered to be a steady-state open system. For exergy analyses, the entire engine was considered to be a control volume and a steady-state open system. Fuel and air enter, and mechanical work, heat loss and exhaust gases leave the control volume at a constant rate. The exergy balance for the control volume can be stated as. where is the exergy transfer rate associated with the heat loss from the control volume to the environment, assumed to be through cooling water; is the exergy work rate, which is equal to the energetic work rate; is the mass ﬂow rate; is speciﬁc ﬂow exergy; and is the exergy destruction (irreversibility) rate. Results and Discussion exergy efficiency increased with increasing engine load. This relationship could be attributed to the reason that brake power increased with increasing engine load, and the other side, there was a positive direct relationship between brake power and exergy efficiency, resulting in an increase of exergy efficiency. Although fuel consumption increased along with increasing engine load, increase in the brake power was much greater than increase in the fuel consumption. On the other hand, an increase in the engine load enhanced combustor temperature which was provided an appropriate condition for combustion and caused an increase in cylinder pressure. At all engine operating conditions, with increasing engine speed, the thermal efficiency at first increased, at moderate speed reached to a maximum amount and finally with more increase in engine speed, the thermal efficiency decreased. The initial increase in thermal efficiency could be attributed to the increase in air to fuel ratio and engine torque which caused an increase in the brake power. Decreasing thermal efficiency in high levels of engine speed could be caused by a decrease in volumetric efficiency of the combustion chamber, because of the time limit on filling cylinder. With increasing biodiesel concentration in the fuel blend, exergy efficiency decreased. The reason could be due to the lower calorific value and the higher viscosity of biodiesel compared to diesel fuel. Conclusions At all engine operating conditions, the exergy efficiency of the engine increased with increasing engine load also with increasing percentages of biodiesel into synthetic fuel, exergy efficiency increased. 43.09% of the fuel exergy was completely destructed and was not convertible to work. The results of optimization indicated that the most exergy efficiency (37.72%) was occurred for the pure diesel at 2036 rpm and 95% load.
format	article
author	G Khoobbakht
author_facet	G Khoobbakht
author_sort	G Khoobbakht
title	Analysis of the Exergy of Combustion the Diesel and Biodiesel Fuel in a DI Diesel Engine
title_short	Analysis of the Exergy of Combustion the Diesel and Biodiesel Fuel in a DI Diesel Engine
title_full	Analysis of the Exergy of Combustion the Diesel and Biodiesel Fuel in a DI Diesel Engine
title_fullStr	Analysis of the Exergy of Combustion the Diesel and Biodiesel Fuel in a DI Diesel Engine
title_full_unstemmed	Analysis of the Exergy of Combustion the Diesel and Biodiesel Fuel in a DI Diesel Engine
title_sort	analysis of the exergy of combustion the diesel and biodiesel fuel in a di diesel engine
publisher	Ferdowsi University of Mashhad
publishDate	2019
url	https://doaj.org/article/877fec5d1c33461ea9e12216ac99392b
work_keys_str_mv	AT gkhoobbakht analysisoftheexergyofcombustionthedieselandbiodieselfuelinadidieselengine
_version_	1718429849704464384
spelling	oai:doaj.org-article:877fec5d1c33461ea9e12216ac99392b2021-11-14T06:34:54ZAnalysis of the Exergy of Combustion the Diesel and Biodiesel Fuel in a DI Diesel Engine2228-68292423-394310.22067/jam.v9i1.65150https://doaj.org/article/877fec5d1c33461ea9e12216ac99392b2019-03-01T00:00:00Zhttps://jame.um.ac.ir/article_33547_53fc3406a26d85131612d48f0d3d2dfe.pdfhttps://doaj.org/toc/2228-6829https://doaj.org/toc/2423-3943Introduction In recent years, the exergy analysis method has been widely used in the design, simulation and performance assessment of various thermal systems. In this regard, this method may be applied to various types of engines for identifying losses and efficiencies. This analysis is based on the second law of thermodynamic. Exergy is a potential or quality of energy. It is possible to make sustainable quality assessment of energy. In this study, the second law of thermodynamics is employed to analyze the quantity and quality of exergy in a fourstroke, four-cylinder, diesel engine using diesel fuel and biodiesel fuel. Materials and Methods Four experiment variables in the present study including the operating parameters, load and speed, and the added volume of biodiesel of diesel fuel were considered as effective factors on the Break exergy efficiency. Designs that can ﬁt model must have at least three different levels in each variable. This is satisﬁed by Central Composite Rotatable Designs (CCRD). Similar to the case of the energy analysis, the same assumptions were valid for exergy analysis; the whole engine was considered to be a steady-state open system. For exergy analyses, the entire engine was considered to be a control volume and a steady-state open system. Fuel and air enter, and mechanical work, heat loss and exhaust gases leave the control volume at a constant rate. The exergy balance for the control volume can be stated as. where is the exergy transfer rate associated with the heat loss from the control volume to the environment, assumed to be through cooling water; is the exergy work rate, which is equal to the energetic work rate; is the mass ﬂow rate; is speciﬁc ﬂow exergy; and is the exergy destruction (irreversibility) rate. Results and Discussion exergy efficiency increased with increasing engine load. This relationship could be attributed to the reason that brake power increased with increasing engine load, and the other side, there was a positive direct relationship between brake power and exergy efficiency, resulting in an increase of exergy efficiency. Although fuel consumption increased along with increasing engine load, increase in the brake power was much greater than increase in the fuel consumption. On the other hand, an increase in the engine load enhanced combustor temperature which was provided an appropriate condition for combustion and caused an increase in cylinder pressure. At all engine operating conditions, with increasing engine speed, the thermal efficiency at first increased, at moderate speed reached to a maximum amount and finally with more increase in engine speed, the thermal efficiency decreased. The initial increase in thermal efficiency could be attributed to the increase in air to fuel ratio and engine torque which caused an increase in the brake power. Decreasing thermal efficiency in high levels of engine speed could be caused by a decrease in volumetric efficiency of the combustion chamber, because of the time limit on filling cylinder. With increasing biodiesel concentration in the fuel blend, exergy efficiency decreased. The reason could be due to the lower calorific value and the higher viscosity of biodiesel compared to diesel fuel. Conclusions At all engine operating conditions, the exergy efficiency of the engine increased with increasing engine load also with increasing percentages of biodiesel into synthetic fuel, exergy efficiency increased. 43.09% of the fuel exergy was completely destructed and was not convertible to work. The results of optimization indicated that the most exergy efficiency (37.72%) was occurred for the pure diesel at 2036 rpm and 95% load.G KhoobbakhtFerdowsi University of Mashhadarticledieselbiodieselexergyresponse surfaceAgriculture (General)S1-972Engineering (General). Civil engineering (General)TA1-2040ENFAJournal of Agricultural Machinery, Vol 9, Iss 1, Pp 155-166 (2019)

Analysis of the Exergy of Combustion the Diesel and Biodiesel Fuel in a DI Diesel Engine

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