Wyniki wyszukiwania - BazTech

1

Numerical study of fuel and turbulence distributions in an automotive-sized scavenged pre-chamber

Bolla Michele, Shapiro Evgeniy, Kotzagianni Maria, Kyrtatos Panagiotis, Tiney Nick, Boulouchos Konstantinos

Combustion Engines

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2019

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R. 58, nr 1

61--67

EN

This article presents a numerical study of the fuel and turbulence distributions in a pre-chamber at spark-time. The study has been conducted in the framework of the H2020 Gas-On project, dealing with the development of a lean-burn concept for an automotive-sized gas engine equipped with a scavenged pre-chamber. The test case considered studies a 7-hole pre-chamber with circumferentially-tilted orifices mounted on the cylinder head of a rapid compression-expansion machine (RCEM), consistent with the experimental test rig installed at ETH Zurich. An accurate description of turbulence and fuel distributions are key quantities determining the early flame development within the pre-chamber. Both quantities have an influence on the overall combustion characteristics and therefore on the engine performance. For this purpose, computational fluid dynamics (CFD) is employed to complement experimental investigations in terms of data completeness. The performance of the Reynolds-averaged Navier-Stokes (RANS)-based turbulence model is compared with large-eddy simulation (LES) through ensemble averaging of multiple LES realizations, in which the fuel injection rate evolution into the pre-chamber has been perturbed. Overall, RANS results show that the distributions of the turbulent kinetic energy and fuel concentration at spark-time agree well with the LES ensemble-averaged counterparts. This constitutes a prerequisite in view of the combustion phase and the accuracy reported provides further confidence in this regard.

2

Thermodynamic model of the ASz-62IR radial aircraft engine

Magryta P., Pietrykowski K., Gęca M.

Prace Instytutu Lotnictwa

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2018

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Nr 1 (250)

36--49

EN

The article presents assumptions of the one-dimensional model of the ASz-62IR aircraft engine. This model was developed in the AVL BOOST software. The ASz-62IR is a nine cylinder, aircraft engine in a radial configuration. It is produced by the Polish company WSK “PZL-Kalisz” S. A. The model is used for calculating parameters of the fuel stream and the air stream in intake system of the engine, as well as for the analyses of the combustion process and the exhaust flow to the external environment. The model is based on the equations describing the isentropic flow. The geometry of the channels and all parts of the model has been mapped on the basis of empirical measurements of the engine elements. The model assumes indirect injection where the gasoline was used as a fuel with the calorific value of 43.5 MJ/kg. The model assumes a mixture of a stoichiometric ratio of 14.5. This model is only part of the overall the ASz-62IR engine model. After the simulation tests on the full model the obtained results confirmed the correctness of the model used to create the mixture. It was found that the AVL BOOST software is good for the implementation of this type of work.

PL

W artykule przedstawiono założenia jednowymiarowego modelu wymiany ładunku z silnika lotniczego ASz-62IR. Model ten został opracowany w programie AVL BOOST. Silnik ASz-62IR jest dziewięciocylindrowym silnikiem lotniczym w układzie gwiazdy. Jest on produkowany przez polską firmę WSK „PZL-Kalisz” S.A. Opracowany model służy do obliczania parametrów strumienia paliwa i powietrza w układzie dolotowym silnika, jak również do analizy procesu spalania i przepływu spalin do środowiska zewnętrznego. Model jest oparty na równaniach opisujących przepływ izentropowy. Geometrię kanałów i wszystkich przepływowych elementów modelu odwzorowano na podstawie empirycznych pomiarów konstrukcji silnika. W modelu założono wtrysk pośredni, a jako paliwo zastosowano benzynę o wartości opałowej 43,5 MJ/kg. Założono stechiometryczną mieszankę o współczynniku 14,5. Opisany model jest tylko częścią całkowitego modelu silnika ASz-62IR. Po wykonaniu badań symulacyjnych pełnego modelu uzyskano wyniki potwierdzające prawidłowość zastosowanego modelu tworzenia mieszanki oraz stwierdzono przydatność oprogramowania AVL BOOST do realizacji tego typu prac.

3

FEV HiFORS: A new passenger car Diesel injector with continuous rate shaping for 2500 bar injection pressure

Grzeschik P., Laumen H.-J.

Combustion Engines

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2014

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R. 53, nr 2

36--44

EN

This paper presents the HiFORS continuously rate shaping injector for injection pressures of 2500 bar and above developed by FEVGmbH and the Institute for Combustion Engines, RWTH Aachen University. The development process from concept definition to hydraulic and deisgn layout, material choice and manufacturing is discussed. The hydraulic operating properties are verified by injection test rig investigations. Optical investigations are conducted in an optically accessible high pressure, high temperature chamber using shadowgraphy and OH chemoluminescence detection, thereby capturing both liquid and gaseous penetration as well as combustion areas. Single cylinder investigations are carried out at a 0.4 dm3 research engine in different operating points from low part load to full load. Compared to a serial production piezo injector, base measurements using conventional square injection profiles already show reduced combustion noise at improved NOx-soot trade-off as well as lowered HC and CO emissions. Detailed investigations at part load operating points explore the potential of different continuous rate shaping patterns, while the injector’s high injection pressure capability of up to 2500 bar and its influence on engine performance is tested at full load operation points.