Wyniki wyszukiwania - BazTech

1

Śruba okrętowa z druku 3D? To jest możliwe

Róg Lucyna

Przegląd Mechaniczny

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2021

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nr 5

18--20

PL

Duże konstrukcje inżynierskie – np. turbiny czy maszyny przemysłowe – powstają nadal w tradycyjnych procesach takich jak kucie, odlewanie czy obróbka skrawaniem. A gdyby „drukować je w 3D”, przyspieszając czas ich powstania i ograniczając koszty? Nad takim rozwiązaniem pracuje konsorcjum 21 partnerów z ośmiu europejskich krajów, w tym Politechnika Wrocławska.

2

Numerical investigation of the hydrodynamic performance of the propeller behind the ship with and without WED

Nadery Alireza, Ghassemi Hassan

Polish Maritime Research

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2020

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nr 4

50--59

EN

The presented paper numerically carries out the investigation of the hydrodynamic performance of the propeller behind the ship with and without wake equalizing duct (WED). It is mounted in front of the propeller in order to equalize the ship’s wake flow and improve the propeller performance. The computational fluid dynamics (CFD) analysis software STAR-CCM solver was adopted to simulate the KP505 propeller behind the KRISO container ship (KCS) using overlapping grid technology and user-defined functions. To obtain the effect of a –duct on propeller performance, the ship bare hull case, the with-propeller case, and the with-propeller-and-duct case are also computed. Together, these computations provide for a –complete CFD comparison of the duct effects. Also, the Taguchi design of the experiment method is applied to investigate three parameters (angle of attack, trailing edge radius, and chord length) of the duct. Finally, the main dimensions are obtained, and the thrust and torque coefficients are presented and discussed for one blade and whole blades during one cycle. Based on the numerical results, it is indicated that good design increases efficiency by 1.67%, and a –bad design may reduce efficiency by 3.25%. Also, the effect of the WED caused to decrease the pressure pulse by 35.9% in the face side of the propeller blade.

3

Operational verification of a ship main power system element choice : case study

Adamkiewicz Andrzej

Journal of KONES

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2019

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Vol. 26, No. 4

7--14

EN

The article refers to results and conclusions on post-emergency repairs of a turbo-charging system of a DEUTZ engine of the SBV 8M 628 type of 1715 kW – the main power unit of a cement carrier. The failure of the turbocharger led to severing of a part of the exhaust outlet valve head. In order to determine the cause of the turbocharger fault, parametric identification of the reference state of the turbocharging system interacting with the ship main power engine has been carried out. The post-emergency servicing of the turbocharger comprised mounting a new blade rim of expansive instruments of smaller capacity than the so far used. Control measurement results of the power system after the replacement of the turbocharger turbine nozzle have been presented. Limitations of correct engine operation have been noted in the range of maximum load with continuous power (MCR). A range of corrective maintenance servicing of fuel equipment has been presented. Using the values of measured torque at the propeller shaft, incorrect interaction between the shaft and the main engine has been noted. A new propeller, adequate to the design operational parameters of the engine characteristics, has been chosen and mounted. The correctness of turbine expansive instrument replacement has been verified by correct interaction between the elements of the power system: propeller – main engine – turbocharging system. Thus, a wider range of economically acceptable ship operation has been obtained.

4

Practical approach to calculating the hydrodynamic oscillating loads of a ship propeller under non-uniform wake field

Ghassemi H.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2018

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nr 56 (128)

9--20

EN

Propellers usually operate in the ship’s stern, where the inflow of the non-uniform wake generates oscillating loads and changes the hydrodynamic performance. Therefore, determination of the forces on propellers and hydrodynamic performance due to a non-uniform wake field are the challenging problems for naval architects and hydrodynamists. The main objectives of the present study are to assess the hydrodynamic performance for a single blade and all the blades. The propeller is a B-series propeller under non-uniform wake field behind the Seiun-Maru (hereafter SM) ship hull. A practical approach is employed to calculate the hydrodynamic oscillating loads of the ship propeller under a non-uniform wake field. Results of the computations on the propeller behind the SM ship, due to a non-uniform wake field, are presented and analyzed using classical mathematical methods over a single cycle. The results show that a variation of thrust with the discussed parameters is the same as that shown for torque, also the blade-frequency of the total force, thrust and torque is an increasing function of radial sections, whereas these parameters decrease with increasing radial blade sections.

5

Mathematical Models Of Mechanical Properties Of Vessel Screw Propellers

Piaseczny L., Rogowski K.

Journal of Polish CIMAC

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2007

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Vol. 2, no 1

399-405

EN

During repairing screw propellers by welding and plastic deformation it is indispensable to know their material features and strength properties relative to the propeller part subject to repair. The authors have conducted statistical and empirical research aimed at determining those features depending on the propeller’s chemical composition and blade thickness. These dependencies are presented in the form of mathematical models useful both cognitively and utilitarian-wise.