Wyniki wyszukiwania - BazTech

1

Simulation tests of a drive shaft and propeller control subsystem for a fast boat

Grządziela Andrzej, Hożyń Stanisław

Polish Maritime Research

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2024

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nr 2

20--28

EN

This paper presents an analysis of the acceleration of a fast boat using a simulation model. Mathematical equations of ship motion dynamics with two types of propeller capabilities are developed using MATLAB and Simulink as simulation tools. The equations are extended to include the acting thrust, resistance, propeller’s performance curves, and the PID governor curve for the acceleration manoeuvre. The application models the dynamic differential equations representing the vessel dynamics in one degree of freedom. MATLAB code was used to develop the ship acceleration as a multibody system. Modules of hydrodynamic forces, resistance, moments, and propeller performances were implemented to simulate the ship manoeuvring process. A comparison of the results for the boat’s propulsion performance with two different propellers and the characteristics of the PID governor, which controls the fuel dose in the gas turbines, was carried out. We present a summary including a comparative analysis of the results for the boat dynamics with and without the PID governor. The results obtained here confirm significant discrepancies between the results of numerical simulations with and without the PID governor.

2

Experimental validation of an FEM model based on lifting theory applied to propeller design software

Grządziela Andrzej, Kraskowski Marek, Król Przemysław, Szturomski Bogdan, Kiciński Radosław

Polish Maritime Research

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2024

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nr 2

67--76

PL

In the process of designing a marine propeller, hydroelasticity effects are neglected in most cases, due to the negligible influence of the blade’s deformation on its hydrodynamic characteristics. However, there are cases where the impact of hydroelasticity is crucial, for example in the case of high skew-back propellers or heavy-loaded composite propellers. Furthermore, the importance of composite propellers is growing due to their wide range of application, for instance in naval ships and unmanned vehicles. Although structural models and two-way fluid-structure interactions are implemented in most commercial CFD solvers, their relevance to the design process is severely limited due to the high computational cost for a single iteration. An effective solution would therefore be to implement a two-way fluidstructure interaction model in the lifting surface software, which is commonly accepted as a design tool due to its relatively low computational time and its applicability to multi-criteria optimisation. This paper presents the results of hydrodynamic analyses of an elastic propeller carried out using in-house software based on the lifting surface flow model, and extended with the FEM model for the blade structure. The results are compared with experimental measurements and computational analyses with the commercial RANS solver STAR-CCM+.

3

Design and operational diagnostics of marine propellers made of polymer materials

Kluczyk Marcin, Grządziela Andrzej, Batur Tomislav

Polish Maritime Research

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2022

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nr 4

115--122

EN

There has been a rapidly growing interest in the use of composite and polymer materials for the construction of marine propellers for over 20 years. The main advantages of these materials are a reduction in the weight of the propeller, increased efficiency due to the hydroelasticity effect, a reduction of the hydroacoustic signature, and a cost reduction for serial production. This paper presents an overview of diagnostic methods that can be applied at the design level and during the operation of marine propellers made of polymeric materials. Non-invasive contact and non-contact-based diagnostic techniques for evaluating the technical state of the propeller are reviewed, and the advantages and disadvantages of qualitative and quantitative methods are identified. Operational diagnostic procedures for propellers are areessential for the safety of vessels at sea. Finally, the structure of a diagnostic system is proposed. It combined diagnosis process with the genesis of damage and the prognosis of the technical condition, i.e. production and in-service diagnostics.

4

The Single Degree of Freedom Simulation Model of Underwater Explosion Impact

Grządziela Andrzej, Załęska-Fornal Agata, Kluczyk Marcin

Archives of Acoustics

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2020

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Vol. 45, No. 2

341--348

EN

The hulls of naval ships are exposed to forces and moments coming from internal and external sources. Usually, these are interactions that can be described mathematically by harmonic and polyharmonic functions. The shock of UNDEX type (underwater explosion) works completely differently and its time waveform is difficult to describe with mathematical functions as pressure vs. time. The paper presents a simplification of physical and mathematical models of 1-D kickoff pressure whose aim is performance the simulation of the external force of the detonation wave. The proposed models were verified and tuned on naval, sea trials. The main goals of the proposed models are to perform simulation calculations of the detonation pressure for different explosion charge weights from different distances of the UNDEX epicentre for the design process of machine foundation. The effects of pressure are transformed as impulses exposed on shock absorber mounted at light shock machine.

5

Method for assessing the dynamics and efficiency of diving fins

Grządziela Andrzej, Szymak Piotr, Piskur Paweł

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 4

139--150

EN

This article presents a method for an evaluation of the dynamic ability and efficiency of diving fins. There is paucity in the literature on the process of selecting optimal fins. As a result, there are efforts made to develop a methodology for selecting fins that meet the proposed criteria. In the present study, an analysis on the two types of fins most popular within the commercial market was conducted. The experiment took place in a test water tunnel fully equipped with a measuring system and strain gauges for recording forced interaction between the moving fin and flowing water. The tested fins rested on an artificial leg, which moved respectively, thereby developing movement algorithms. This forced fluid flow was implemented by a pump that was able to control the fluids velocity, and a non-invasive method involving an ultrasonic flow meter was used to measure the fluids velocity. Finally, the fin efficiency was calculated as the ratio of multiplication of generated thrust to electrical energy consumption whilst also considering the mechanical efficiency of the leg manipulator. The results of these experiments are discussed in depth and a method is created for the subsequent stage in which a new type of fins called biomimetic is to be analyzed and compared.

6

Fuzzy identification of the reliability state of the mine detecting ship propulsion system

Pająk Michał, Muślewski Łukasz, Landowski Bogdan, Grządziela Andrzej

Polish Maritime Research

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2019

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nr 1

55--64

EN

The study presents the evaluation and comparative analysis of engine shaft line performance in maritime transport ships of the same type. During its operation, a technical system performs functions for which it was designed. It goes through different states. Dynamic state changes of a rotational system can be identified by means of its vibration measurement. For this purpose, a research was carried out which involved recording vibrations of the analysed rotational systems. The recordings were used for calculating selected characteristics in the time-domain, where one of the most unique is the value of the normalized mutual correlation function. On the basis of the concentration values, the characteristics which unambiguously determine the ability state were selected for further studies. Then an identification method for rotational system non-coaxiality was proposed. The method involves using fuzzy clustering. According to this method the values of input signal characteristics were used to formulate fuzzy clusters of system ability and inability states. The method can be used for identifying the current state of the system. The study presents the results of the application of this method in engine turbine shaft lines of minesweepers, with the rotational system selected as an example. It needs to be noted that the efficiency of identifying the operating state of the system with this method is higher than with other methods described in the literature by authors who deal with this issue. The research results have a significant impact on the evaluation of mechanical properties of the studied objects and directly affect operational states of mechanical systems, including those installed in minesweepers, thus determining their reliability.

7

Marine diesel engine common rail injectors monitoring with vibration parameters

Kluczyk Marcin, Grządziela Andrzej

Diagnostyka

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2019

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Vol. 20, No. 3

37--44

EN

The paper presents a results of vibration tests of common rail injectors operating in diesel engines. The most common methods of diagnosing common rail injectors (CR) as well as the most common damage of injectors of this type have been described. The results and analyzes of tests obtained during measurements on two different test stands were presented. Obtained results allowed for the preliminary determination of diagnostically sensitive parameters, which may allow the development of the injector diagnostics method without the need to stopping the engine.

PL

W artykule przedstawiono wyniki badań drganiowych wtryskiwaczy Common Rail pracujących w silnikach o zapłonie samoczynnym zasilanych. Opisano najpowszechniej stosowane metody diagnozowania wtryskiwaczy Common Rail (CR), jak również najczęstsze uszkodzenia wtryskiwaczy tego typu. Zaprezentowano wyniki i analizy badań uzyskane podczas pomiarów na dwóch różnych stanowiskach testowych. Uzyskane wyniki pozwoliły na wstępne określenie parametrów wrażliwych diagnostycznie, co może pozwolić na opracowanie metody diagnostyki wtryskiwaczy bez potrzeby zatrzymywania silnika.