Journal of Mechanical Engineering 51 (2005) 12

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Analysis of the In-Cylinder Flow Structures Generated by the Engine Induction System – a Comparison of Experimental and Simulated Data

Corresponding author - Samuel Rodman Oprešnik

Authors - Sašo Prijatelj - Tomaž Katrašnik - Ferdinand Trenc - Frančišek Bizjan

Abstract

A comparison and analysis of laser Doppler anemometry (LDA) measurements and a computed fluid dynamics (CFD) simulation of the in-cylinder flow structures generated by an engine induction system is presented in this paper. An octagonal glass model with a moving piston complementary to a real engine cylinder was applied in the analysis. Good agreement between the measured and simulated patterns of the flow structures and the inlet-valve discharge coefficients was obtained. In general, this study shows that in-cylinder CFD predictions yield reasonably accurate results that help to improve the knowledge of the air-flow characteristics during the intake stroke. CFD therefore represents an effective design tool for developing less-polluting and more efficient internal combustion engines.

Keywords - internal combustion engine, computational fluid dynamics, CFD, air flow characteristics, laser Doppler anemometry

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 51(2005)12, 744-756
UDK 621.43.01:004.94

Analysis of the In-Cylinder Flow Structures Generated by the Engine Induction System – a Comparison of Experimental and Simulated Data (pdf)

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A Model of Effective Data Management From Exploitation – A Case of Domestic-Appliance Production

Corresponding author - Peter Meža

Authors - Andrej Polajnar - Srečko Glodež

Abstract

A company that wants to stay competitive has to keep up to date with the quality of products on the market, and constantly has to remove all the defects from its critical products. For this reason companies, depending on their size and type of activity, need a specific data-information integration model for the exploitation phase. Structured exploitation data increases the level of work quality and incorporates experience from former lines of products in the process of development or improving current products. For the needs of management quality the recurrent feedback loop was supplemented with the engineer model of service order, which includes an inventory of defect mechanisms. The information flow between fieldwork repairers and the company is illustrated in the case of a production company. The specification of the data model, which is based on defect presentation, presents the knowledge of defect mechanisms and causes. We used the model of the codification of defects. It covers the total area of states and causes in the structured form, which enables the company to easily acquire data as well as organized knowledge on the basis of typified defects that occur in the product lifecycle. Product-repair data available in one place enables a direct data transformation back to the feedback loop of the company. The model presented in this paper offers support to the TQM methods as well as the basis for carrying out correction measures in the production company. The structured data in the service-order model make it possible to navigate in the product-failure net.

Keywords - product quality, reliability, warranty analysis, technical services

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 51(2005)12, 757-770
UDK 658.56:658.818.3

A Model of Effective Data Management From Exploitation – A Case of Domestic-Appliance Production (pdf)

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The Process of Manufacturing-Capability Development in Industrial Clusters – A Case Study of the Automotive Cluster of Slovenia

Corresponding author - Tatjana Fulder

Authors - Iztok Palčič - Andrej Polajnar - Petja Pižmoht

Abstract

Industrial clusters are interesting concepts of network collaboration that are also well established in the Slovenian business environment. They represent a new challenge for research in the field of production and operations management. The reasons for cluster formation have been explored for many years, but there is little research that explores the strategic consequences of this type of collaboration. This paper deals with the manufacturing-capability development process and with the research conducted in the industrial clusters. The research is based on a case-study methodology.

Keywords - industrial clusters, resource-based view, manufacturing capability, case study

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 51(2005)12, 771-785
UDK 65.014.13

The Process of Manufacturing-Capability Development in Industrial Clusters – A Case Study of the Automotive Cluster of Slovenia (pdf)

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Modeling and the Analysis of Parameters in the Torsional-Oscillatory System Equivalent to the Diesel Engines in Heavy-Duty Vehicles

Corresponding author - Ivan Filipović

Authors - Vlatko Doleček - Dževad Bibić

Abstract

This paper describes the procedure for modeling and calculating the parameters of the torsional-oscillatory system equivalent to multi-cylinder, in-line, water-cooled diesel engines in heavy-duty vehicles. As a result of a literature search and our own investigation we present models and algorithms for defining the following parameters: the moments of inertia of oscillatory masses, the stiffnesses of engine-crankshaft segments, the external and internal damping in the torsional-oscillatory system, and the excitation of gas and inertia forces. Due to the specific characteristics of the viscoelastic element, somewhat more emphasis is placed on the viscoelastic damper of torsional oscillations in internal combustion engines. For the proposed equivalent torsional-oscillatory system, a suitable model and our own calculation program were developed. The analysis of the amplitude of twisting of individual system components in an actual engine, with and without a torsional-oscillations damper, is given. These results are compared to the experiments conducted on an engine test-bench. The agreement between the analytical and experimental results suggests that the proposed procedure for modeling and computing the parameters of the equivalent torsional-oscillatory systems can be successfully applied in practice.

Keywords - diesel engine, heavy-duty vehicles, torsional oscillations, mathematical models

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 51(2005)12, 786-797
UDK 621.436:629.351

Modeling and the Analysis of Parameters in the Torsional-Oscillatory System Equivalent to the Diesel Engines in Heavy-Duty Vehicles (pdf)

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Numerical Modeling of Mixing in a Vessel with a Rushton Impeller

Corresponding author - Matjaž Hriberšek
Authors - Matej Zadravec

Abstract

This paper presents numerical modeling of mixing a Newtonian fluid in a stirring vessel with a Rushton impeller. The stationary turbulent flow is governed by the time-averaged Navier-Stokes equations. For the numerical approach, a two-equation turbulence model with the finite-volume method was used. The focus is on impeller rotation, a determination of the stirrer power and a simplification that can lead to faster solving of complicated discreet models.

Keywords - Rushton impeller, numerical modeling, turbulent flow, flow conditions

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 51(2005)12, 798-809
UDK 66.063:532.5

Numerical Modeling of Mixing in a Vessel with a Rushton Impeller (pdf)

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