Temat: propeller - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Drag and Torque on Locked Screw Propeller
Autorzy:: Tabaczek, T.
Bugalski, T.
Tematy:: Ship Operation
Locked Screw Propeller
Propulsion System
Propeller Drop
Propeller Torque
CFD Computations
Hydrodynamics
Sailboat Fixed Blade Propeller; Pokaż więcej
Wydawca:: Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Powiązania:: https://bibliotekanauki.pl/articles/117621.pdf Link otwiera się w nowym oknie
Opis:: Few data on drag and torque on locked propeller towed in water are available in literature. Those data refer to propellers of specific geometry (number of blades, blade area, pitch and skew of blades). The estimation of drag and torque of an arbitrary propeller considered in analysis of ship resistance or propulsion is laborious. The authors collected and reviewed test data available in the literature. Based on collected data there were developed the empirical formulae for estimation of hydrodynamic drag and torque acting on locked screw propeller. Supplementary CFD computations were carried out in order to prove the applicability of the formulae to modern moderately skewed screw propellers.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Blade cup method for cavitation reduction in marine propellers
Autorzy:: Samsul, M. Burak
Tematy:: marine propeller
computational fluid dynamics
propeller cup
cupping
cavitation
propeller efficiency
vibration
noise
erosion; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/1573632.pdf Link otwiera się w nowym oknie
Opis:: Energy efficiency has become more important in every industry and daily life. Designing and building a more efficient marine vehicle can lead to lower fuel consumption and a longer lifetime for the components of the vehicle. Erosion caused by cavitation reduces the service life of the propeller and the related components in the propulsion and maneuvering system. Reducing cavitation leads to a longer life for these components. This paper aims to explain and investigate propeller blade cup as a cavitation reduction method for marine propellers. A cavitating no-cup propeller is created and analyzed then the cupped version of this propeller is generated and analyzed to compare with the no-cup propeller. Cavitation results of these propellers are investigated. In addition, the thrust, torque, and efficiency of the propellers are compared.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: The influence of structural features on vibration of the propeller engine test bench
Autorzy:: Ostapski, W.
Aromiński, A.
Tułodziecki, M.
Tematy:: propeller engine test bench
propeller vibration
digital modelling
CAD
construction; Pokaż więcej
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:: https://bibliotekanauki.pl/articles/280586.pdf Link otwiera się w nowym oknie
Opis:: The paper concerns the prototype of a propeller engine test bench stand designed for durability tests of airplane piston engines of 150-250 kW power range (Ostapski, 2011b, 2008). The technical data of the prototype engines to be tested on the bench have been adopted. It is obvious that at the beginning of the design process there is no information about the vibration spectrum of the propeller shaft, which is at the production process at that time. The basic 3D model of test bench constructional variants are presented in the article. Modes and frequencies of free vibrations are defined in ANSYS environment for both the loaded and unloaded structure and for various design variants. The estimated vibration frequency range for the propeller shaft varies from ƒ = 22 to ƒ = 360 Hz. In such a case, there is no easy way for rational test bench construction to be completely “untuned” to the vibration forcing load. This is the reason for introducing the basic model and few its modifications. After first engine tests, it should be possible to separate natural vibrations of the bench and high amplitude vibrations of the engine.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Impact of propeller emergence on hull, propeller, engine, and fuel consumption performance in regular head waves
Autorzy:: Ghaemi, Mohammad Hossein
Zeraatgar, Hamid
Tematy:: ship dynamics
ship propulsion system
propeller ventilation
propeller emergence
sea waves; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/32898210.pdf Link otwiera się w nowym oknie
Opis:: In this study, the impact of propeller emergence on the performance of a ship (speed), propeller (thrust, torque, and RPM), a diesel engine (torque and RPM) and fuel consumption are analysed under severe sea conditions. The goal is to describe the variation in the system variables and fuel consumption rather than analysing the motion of the ship or the phenomenon of propeller ventilation in itself. A mathematical model of the hull, propeller, and engine interactions is developed in which the propeller emergence is included. The system parameters are set using model experiments, empirical formulae, and available data for the engine. The dynamic response of the system is examined in regular head waves under submerged and emerged conditions of the propeller. The pulsatility and the extent of variation of 20 selected variables for the coupled system of hull, propeller, and engine are elaborated using quantitative and qualitative terms and absolute and relative scales. The simulation begins with a ship moving on a straight path, in calm water, with a constant speed for the ship, propeller and engine under steady conditions. The ship then encounters regular head waves with a known time series of the total resistance of the ship in waves. Large motions of the ship create propeller emergence, which in turn reduces the propeller thrust and torque. This study shows that for a specific ship, the mean ship speed, shaft angular velocity, and engine power were slightly reduced in submerged conditions with respect to calm water. We compared the mean values of the variables to those in the emerged condition, and found that the shaft angular velocity was almost the same, the ship speed was considerably reduced, and the engine power significantly dropped with respect to calm water. The ratios of the amplitude of fluctuation to the mean (Amp/Mean) for the ship speed and angular velocity of the shaft under both conditions were considerable, while the Amp/Mean for the power delivered by the engine was extremely high. The outcomes of the study show the degree of influence of propeller emergence on these variables. We identify the extent of each change and categorise the variables into three main groups based on the results.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Cavitation of a Propeller and Influence of an Wake Equalizing Duct
Autorzy:: Martinas, G.
Tematy:: Cavitation
Propeller
Wake Equalizing Duct (WED)
Propeller-Excited Vibrations
Viscous Resistance Forces
Cavitation of Propeller
WED Device
Propulsion Performance; Pokaż więcej
Wydawca:: Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Powiązania:: https://bibliotekanauki.pl/articles/117619.pdf Link otwiera się w nowym oknie
Opis:: The wake equalizing duct (WED) is one of the most commonly used energy saving devices for improving the propulsion performance of a ship; and reducing the propeller-excited vibrations and viscous resistance forces. During the last three decades considerable research and development activities have taken into place within this context. Most of these devices are used to improve propulsive efficiency, but some of them aims to improve other performance characteristics, such as cavitations, vibration, noise, maneuverability, etc. Marine propellers are the most common propulsion systems; nevertheless, it is possible to improve its propulsive performance using additional auxiliary propulsor devices (unconventional propulsors). Two versions of an existing ship in normal version and fitted with WED device were analyzed in order to demonstrate the influence on the WED device on the propeller cavitations . It was determined that the values for the pressure coefficient is 1.98 for without WED situation and 2.029 for WED situation. The difference is not so significant that, the conclusion is that WED device did not have influence over the cavitations of the propeller. Either optimization of dimension and form of WED did not help in reducing negative effects of cavitations. Not being a study in this paperwork, to decrease the cavitations we have other choices including a sound design of the propeller biased to improve the propeller behavior in cavitations. WED is clearly not a choice.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: CFD and FEM model of an underwater vehicle propeller
Autorzy:: Chruściel, T.
Ciba, E.
Dopke, J.
Tematy:: ROV
ROV propeller
semi-open duct for horizontal propellers
rapid prototyping propeller; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/260502.pdf Link otwiera się w nowym oknie
Opis:: Within the framework of the project for design and optimization of the Remotely Operated Vehicle (ROV), research on its propulsion has been carried out. The entire project was supported by CFD and FEM calculations taking into account the characteristics of the underwater vehicle. One of the tasks was to optimize the semi-open duct for horizontal propellers, which provided propulsion and controllability in horizontal plane. In order to create a measurable model of this task it was necessary to analyze numerical methodology of propeller design, along with the structure of a propellers with nozzles and contra-rotating propellers. It was confronted with theoretical solutions which included running of the analyzed propeller near an underwater vehicle. Also preliminary qualitative analyses of a simplified system with contra-rotating propellers and a semi-open duct were carried out. The obtained results enabled to make a decision about the ROVs duct form. The rapid prototyping SLS (Selective Laser Sintering) method was used to fabricate a physical model of the propeller. As a consequence of this, it was necessary to verify the FEM model of the propeller, which based on the load obtained from the CFD model. The article contains characteristics of the examined ROV, a theoretical basis of propeller design for the analyzed cases, and the results of CFD and FEM simulations.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: The influence of propeller emergence on the load of a marine engine of a ship sailing on irregular wave
Autorzy:: Szelangiewicz, T.
Żelazny, K.
Tematy:: ship motions on irregular wave
propeller emergence
decrease in torque value of a propeller; Pokaż więcej
Wydawca:: Akademia Morska w Szczecinie. Wydawnictwo AMSz
Powiązania:: https://bibliotekanauki.pl/articles/360221.pdf Link otwiera się w nowym oknie
Opis:: When a ship is saling on waves the relative motions occur which result in propeller emergence, and as a consequence – propeller thrust reduction which results in a decrease in the ship’s speed. Propeller emergence is also accompanied by the decrease in torque values, with which the propeller affects the marine engine. The article presents both calculation results and the algorithm for calculating the decrease in torque of the propeller during ship motions on irregular wave.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Mathematical model of radial passive magnetic bearing
Autorzy:: Matuszewski, L.
Falkowski, K.
Tematy:: propeller
ring motor
magnetic bearing; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/258724.pdf Link otwiera się w nowym oknie
Opis:: In the article a mathematical model of radial passive magnetic bearings applicable to ocean engineering units has been presented. The application of the bearings in ship thrusters should increase durability of propulsion systems and give lower maintenance costs. The rotor of thruster’s electric motor is suspended in magnetic field generated by radial passive magnetic bearings. However the maintaining of axial direction of the rotor must be controlled with electromagnets equipped with a high-dynamic controller. The risk of application of the magnetic bearings results from very low stiffness of the unit in comparison with rolling bearings. Also construction of the bearing should be different due to gyroscope effect and high forces generated during ship manoeuvring. The physical model performs correctly if electromagnets are controlled properly; and, technological problem with sealing system seems more significant than power supply to electromagnets winding. The equations presented in the article are necessary to build algorithms of a digital controller intended for on-line controlling magnetic bearing in axial direction.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Effects of rudder and blade pitch on hydrodynamic performance of marine propeller using CFD
Autorzy:: Quang, Pham Ky
Hung, Phan Van
Cong, Nguyen Chi
Tung, Trinh Xuan
Tematy:: rudder
blade pitch
propeller
CFD; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/32899108.pdf Link otwiera się w nowym oknie
Opis:: The use of computational fluid dynamics (CFD) to predict internal and external flows has risen dramatically in the past decade. This research aims to use the commercial software, ANSYS Fluent V.14.5, to illustrate the effects of the rudder and blade pitch on the hydrodynamic performance of the marine propeller by experimenting with propellers and rudders of the M/V Tan Cang Foundation ship, which has designed conditions as follows: diameter of 3.65 m; speed of 200 rpm; average pitch of 2.459 m; boss ratio of 0.1730. Using CFD, the characteristic curves of the marine propeller and some important results showed that the maximum efficiency of the propeller is 0.66 with the open water propeller and 0.689 with the rudder‒propeller system at the advance ratio of 0.6. The obtained outcomes of this research are a significant foundation to calculate and design an innovative kind of propulsion for ships with high performance.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Prediction of propeller forces during ship maneuvering
Określanie sił śruby napędowej podczas manewrowania statkiem
Autorzy:: Abramowski, T.
Tematy:: ship manoeuvring
ship propeller forces; Pokaż więcej
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:: https://bibliotekanauki.pl/articles/279647.pdf Link otwiera się w nowym oknie
Opis:: A method is proposed for the determination of propeller forces during ship maneuvering. Artificial neural networks were applied to the performance prediction of a propeller working under such conditions as braking, stopping and running astern. Furthermore, an effect of oblique motion of a maneuvering ship, is studied by means of computational fluid dynamics methods. Wake distributions in the propeller plane are presented when the drift angle gets higher. A simple application example of the discussed methods is presented for a real case of a maneuvering ship.
W pracy zaproponowano metodę służącą do określania sił śruby napędowej podczas manewrowania statkiem. Do wyznaczenia charakterystyk śruby napędowej pracujacej w warunkach hamowania, zatrzymania i ruchu wstecz zastosowano sztuczne sieci neuronowe. Ponadto, przy pomocy metod numerycznej mechaniki płynów uwzględniono efekt skośnego ruchu kadłuba manewrującego statku. Zaprezentowano obliczone podczas zwiększania się kąta dryfu rozkłady strumienia nadążającego w płaszczyźnie kręgu śrubowego. W oparciu o prosty przykład przedyskutowano możliwość zastosowania zaprezentowanej metody dla rzeczywistego przypadku manewrującego statku.
Dostawca treści:: Biblioteka Nauki

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