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Assessment of the Influence of the Propeller’s Geometry on Acoustic Parameters of Propeller Drive System

Nowacki Marcin

Journal of Mechanical and Transport Engineering

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2019

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Vol. 71, No 2

15--23

EN

The operation of propeller propulsion systems is conditioned by the fulfillment of increasingly stringent admissible standards related to noise emission. Good drive parameters indicate the purposefulness of their use. On the other hand, the constraints in the form of noise reduction contribute to the search for ways to develop the geometry of the so-called "Silent propellers”. This geometry depends on the aerodynamic parameters of the propeller profile, its rotational speed, the number of blades, pitch, etc. Determining the relationship between these parameters is crucial to the development of a new construction. Therefore, the stationary tests of available construction of propellers in terms of their acoustic impact on the surroundings were carried out. On the basis of the research, the structure analysis wasperformed on the acoustic parameters of the drive.

PL

Eksploatacja śmigłowych układów napędowych jest uwarunkowana spełnieniem coraz bardziej rygorystycznych dopuszczalnych norm związanych z emisją hałasu. Dobre parametry napędowe wskazują na celowość ich stosowania. Natomiast stawiane uwarunkowania w postaci ograniczenia hałasu przyczyniają się do poszukiwania sposobów na opracowanie geometrii tzw. „cichych śmigieł”. Geometria ta zależy od parametrów aerodynamicznych profilu śmigła, jego prędkości obrotowej, liczby łopat, skoku itp. Wyznaczenie zależności między tymi parametrami jest kluczowe do opracowania nowej konstrukcji. W związku z tym przeprowadzono badania stanowiskowe dostępnych konstrukcji śmigieł pod względem ich oddziaływania akustycznego na otoczenie. Na podstawie badań przeprowadzono analizę wpływu konstrukcji na parametry akustyczne napędu.

2

Dynamic interaction of the cavitating propeller tip vortex with the rudder

Szantyr J. A.

Polish Maritime Research

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2007

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nr 4

10-14

EN

The hydrodynamic interaction between the ship propeller and the rudder has many aspects. One of the most interesting is the interaction between the cavitating tip vortex shed from the propeller blades and the rudder. This interaction leads to strongly dynamic behaviour of the cavitating vortex, which in turn generates unusually high pressure pulses in its vicinity. Possibly accurate prediction of these pulses is one of the most important problems in the hydrodynamic design of a new ship. The paper presents a relatively simple computational model of the propeller cavitating tip vortex behaviour close to the rudder leading edge. The model is based on the traditional Rankine vortex and on the potential solution of the dynamics of the cylindrical sections of the cavitating kernel passing through the strongly variable pressure field in the vicinity of the rudder leading edge. The model reproduces numerically the experimentally observed process of initial compression of the vortex kernel in the high pressure region near the stagnation point at the rudder leading edge and subsequent explosive growth of the kernel in the low pressure region further downstream. Numerical simulation of this process enables computation of the additional pressure pulses generated due to this phenomenon and transmitted onto the hull surface. This new numerical model of the cavitating tip vortex is incorporated in the modified unsteady lifting surface program for prediction of propeller cavitation, which has been successfully used in the process of propeller design for several years and which recently has been extended to include the effects of propeller – rudder interaction. The results of calculations are compared with the experimental measurements and they demonstrate reasonable agreement between theory and physical reality.

3

Recent computational and experimental metods for study pressure distribution over the propeller blades

Pesetskay N., Pesetsky V.

Research Bulletin / Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics

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2001

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nr 12

35-38

EN

The vortex lattice method and PSP method were used in calculations of pressure distribution. The pressure distribution over the surface of rotating blades was measured in the TsAGI T-104 wind tunnel. It is an open-jet subsonic wind tunnel of 7 meters nozzle diameter with the speed varying within the range of 0-120 m/sec. The model was investigated in the whole speed range, rotating 7000 rpm at different angles of blade setting beta=15°. 22.5°. 30°, 40° (beta- angle of blade setting at the relative radius r7R=0.75). Numerical results are compared to experimental results.