Autori: Nicholas C. BUZBUCHI

Editorial: Bulletin of the Marine Engineering Society in Japan (MESJ), the VI-th International Symposium on Marine Engineering ISME 2000, Tokyo, 2000.

Rezumat:

Articolul propune realizarea unei analize armonice a fortei de impingere si a momentului dezvoltate de propulsorul naval, printr-o metoda predictiva ale acestor excitatii induse de elice in linia de arbori, in stadiul de proiectare. S-au utilizat doua metode semiteoretice bazate pe teoria liniei portante, prima fiind semiteoretica, fondata pe hartile de siaj determinate experimental si pe teoria directa a lui Prandtl, iar a doua pe o teorie amplificata a coeficientilor de inductie ai lui Lerbs, ceea ce s-a constituit intr-o metoda analitica ce utilizeaza numai a diagramelor serie ale elicei si a relatiilor empirice pentru siaj si suctiune.
Lucrarea evidentiaza simplitatea si acuratetea celei de-a doua metode, cu remarcarea originalitatii folosirii unei functii in doua variabile pentru circulatia in jurul profilelor palelor elicei: unghiul de rotatie si raza palei. S-au prezentat si rezultatele unor validari experimentale, in buna concordanta cu calculul.
The paper is an attempt to the harmonic structure computation of the marine propeller torque and thrust, being predictive methods of propeller excitations induced in the marine engine shafting system for the design stage. Two quasi-steady methods using the lifting line theory, the first being semi-theoretical due to the wake field experimentally determined and based on the direct Prandtl theory, and the second one based on a developed Lerbs induction coefficients, an analytical method using only the propeller series diagrams and general empirical formulae for the wake and suction coefficient, have been presented.
The paper shows the simplicity and accuracy of the last method, as a primary information on the propeller excitations, and this procedure takes into account a non-dimensional expression of the circulation, as a two-dimension function of the blade radius and angle of rotation. A validation calculation with experiments of propeller excitations induced into the shafting system is analyzed, showing acceptable agreement between calculated and measured excitations.

Cuvinte cheie: Motor naval, linie de arbori, forta de impingere si momentul propulsorului naval // Marine engine, Engine Shafting System, Propeller Torque and Thrust