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Zbigniew Korczewski

Statistical analysis of sea accidents and breakdowns in the Polish Navy

This paper presents the results of systematic, statistical approach to naval accidents and breakdowns which occurred in the Polish Navy between years 1985 - 2004. Additionally, the author of this work has made an initial assessment of the human factor. Human errors, which appeared on considered warships in the examined period of time, have been analyzed in the overall number of accidents and breakdowns.

Open access

Zbigniew Korczewski

Exhaust gas temperature measurements in diagnostic examination of naval gas turbine engines

The first part of the article is limited to the presentation of the results of diagnostic examination of a three-shaft engine with a separate power turbine, operating in steady-load states. The here presented diagnostic analyses and syntheses based on a simplified mathematical model of thermal and flow processes taking place in the combustion chamber, which was used for deriving the equation describing the average steady-state temperature of the exhaust gas flow at the outlet cross-section of the chamber.

Open access

Zbigniew Korczewski

Identification of service failures of cylinder valves of ship piston combustion engines

This paper presents selected diagnostic problems of charge exchange system of ship piston combustion engines. Theoretical background of wear process of cylinder valves was highlighted in the aspect of identification and sources of known and identifiable states of unserviceability. The presented results of endoscopic examinations concern failures of cylinder valves of the engines installed on Polish Navy ships.

Open access

Zbigniew Korczewski

Entropy function application in the selection process of diagnostic parameters of marine diesel and gas turbine engines

The article presents the method of analysing the diagnostic informativeness of the parameters characterizing gas dynamic processes observed inside the working spaces of marine diesel and gas turbine engines. The entropy function was used as the measure of indeterminacy of the identified set of engine unserviceability states. Based on numerical simulation experiments of the analysed gasodynamic processes, the amount of introduced diagnostic information was assessed and the most adequate parameters for the technical state of the engine were selected. These parameters compose the minimised set of diagnostic parameters which make it possible to assess unmistakably the technical state of the examined working spaces.

Open access

Zbigniew Korczewski

Abstract

The second part of the article describes the technology of marine engine diagnostics making use of dynamic measurements of the exhaust gas temperature. Little-known achievements of Prof. S. Rutkowski of the Naval College in Gdynia (now: Polish Naval Academy) in this area are presented. A novel approach is proposed which consists in the use of the measured exhaust gas temperature dynamics for qualitative and quantitative assessment of the enthalpy flux of successive pressure pulses of the exhaust gas supplying the marine engine turbocompressor. General design assumptions are presented for the measuring and diagnostic system which makes use of a sheathed thermocouple installed in the engine exhaust gas manifold. The corrected thermal inertia of the thermocouple enables to reproduce a real time-history of exhaust gas temperature changes.

Open access

Zbigniew Korczewski

Application of expert systems in diagnostics, management and logistics

There has been demonstrated base terms concerning expert systems and analysis of their organisation structure. Some possibilities of the expert knowledge codification worked out on the basis of different application of the object-attribute-value triplets have been presented as well.

Open access

Zbigniew Korczewski

An overview of the didactic and scientific activity at the faculty of mechanical and electrical engineering of the Polish Naval Academy

The article characterises the didactic and scientific activity at the Faculty of Mechanical and Electrical Engineering of the Polish Naval Academy. The current didactic offer and the areas of current research work are presented, along with main characteristics expected from the naval-specialisation graduate majoring in mechanics and machinery construction, in the context of the Polish Navy technical staff education system. Discussed are the subjects of research activities initiated in particular Faculty units, and leading scientific problems which have been studied for years within the field of widely understood utilisation of naval technology.

Open access

Zbigniew Korczewski

Operational causes of fatigue failures within passages of gas turbine engines

In this paper a short presentation of fatigue wear process of structural elements of gas turbine engines has been given. The primary causes of fatigue crack formation within engine mechanical system and flow passages have been highlighted. Special attention was paid to low-cycle fatigue associated with unsteady heat-and-gas-flow processes developed in the passages. The selected damages have been demonstrated of gas flow paths of the engines operating in aviation, navy and power industry, along with origins of their formation and growth.

Open access

Zbigniew Korczewski

Abstract

The article discusses the problem of diagnostic informativeness of exhaust gas temperature measurements in turbocharged marine internal combustion engines. Theoretical principles of the process of exhaust gas flow in turbocharger inlet channels are analysed in its dynamic and energetic aspects. Diagnostic parameters are defined which enable to formulate general evaluation of technical condition of the engine based on standard online measurements of the exhaust gas temperature. A proposal is made to extend the parametric methods of diagnosing workspaces in turbocharged marine engines by analysing time-histories of enthalpy changes of the exhaust gas flowing to the turbocompressor turbine. Such a time-history can be worked out based on dynamic measurements of the exhaust gas temperature, performed using a specially designed sheathed thermocouple.

The first part of the article discusses possibilities to perform diagnostic inference about technical condition of a marine engine with pulse turbocharging system based on standard measurements of exhaust gas temperature in characteristic control cross-sections of its thermal and flow system. Selected metrological issues of online exhaust gas temperature measurements in those engines are discusses in detail, with special attention being focused on the observed disturbances and thermodynamic interpretation of the recorded measuring signal. Diagnostic informativeness of the exhaust gas temperature measurements performed in steady-state conditions of engine operation is analysed in the context of possible evaluations of technical condition of the engine workspaces, the injection system, and the fuel delivery process.

Open access

Zbigniew Korczewski

Exhaust gas temperature measurements in diagnostic examination of naval gas turbine engines: Part II Unsteady processes

The second part of the article presents the results of operating diagnostic tests of a two- and three-shaft engine with a separate power turbine during the start-up and acceleration of the rotor units. Attention was paid to key importance of the correctness of operation of the automatic engine load control system, the input for which, among other signals, is the rate of increase of the exhaust gas flow temperature. The article presents sample damages of the engine flow section which resulted from disturbed functioning of this system. The unsteady operation of the compressor during engine acceleration was the source of excessive increase of the exhaust gas temperature behind the combustion chamber and partial burning of the turbine blade tips.