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Numerical simulation of the ducted propeller and application to a semi-submerged vehicle

100%

Zou J. , Tan G. , Sun H. , Xu J. , Hou Y.

Polish Maritime Research

2020

tom nr 2

19--29

The self-propulsion test of underwater vehicles is the key technique for predicting and evaluating the navigation performance of these submersibles. In this study, the numerical simulation of a standard propeller JD7704+Ka4-70 is first presented and the results are compared with experiments to validate the numerical approaches. The reason why the propulsion efficiency of the ducted propeller is higher than that of the conventional propeller is explored. Then, the paper proposes a series of numerical simulations conducted to test the performance of the ducted propeller designed according to the JD7704+Ka4-70 in order to match with the unmanned semi-submerged vehicle (USSV), and the propeller’s open water characteristic curves are obtained. The results show a reasonable agreement with the regression analysis. Afterwards, the numerical simulations focus on a self-propulsion test of the USSV with the designed ducted propeller and the self-propulsion point is obtained. The streamlines through the hull as well as the ducted propellers are clearly obtained, together with the velocity distributions of the propeller plane. The results vividly demonstrate the hydrodynamic performance of the USSV with the designed propellers. In this paper, all the CFD simulations are based on the numerical software, Star-CCM+, and use the Reynolds-averaged Navier‒Stokes (RANS) equations with the shear stress transport (SST) k-omega turbulence model.

Selection of the most suitable method to split the resistance increment into components related to individual propellers of double-ended ferry

88%

Jarzyna H.

Archives of Civil and Mechanical Engineering

2007

tom Vol. 7, no 3

143-150

The resistance increment [...] measured in model propulsion tests of a double-ended ferry with the pushing aft propeller SR and the pulling fore propeller SD is to be split into two components: [...] and [...] related to each of the propellers. The splitting procedure based on the measured magnitudes is possible only when additional assumptions are made. Two procedures are presented in this paper. The first procedure, i = l, is directly related to the components of resislance increment [...] and [...]. The second procedure, i = 2, is related lo the components [...] and [...] attributed to individual propellers. In both procedures the same assumptions are used for splitting. Proposed assumptions are based on the proportion of propeller thrust TR and TD, or on the proportion of the delivered power [...] and [...]. Procedures combined with assumptions define the methods and are denoted Kij where subscript refers to the assumption. Two prerequisites were formulated. Both have to be satisfied by methods of practical importance: Above prerequisites are satisfied only by the K11 and K21 methods. The methods KI3 and K23 satisfy only the first prerequisite.

Pomierzoną w modelowych badaniach napędowych promów symetrycznych globalną zmianę oporu kadłuba [...] wskutek działania śruby rufowej SR i dziobowej SD należy podzielić na składniki [...] i [...] związane z każdą ze śrub. Podział taki możliwy jest pod warunkiem przyjęcia dodatkowych założeń. Praca analizuje możliwe założenia w dwu grupach proceduralnych. Procedura pierwsza, i = l, wiąże bezpośrednio zmiany [...] i [...] z hipotezami zmian. Procedura druga, i = 2, wiąże zmiany [...] z tymi samymi hipotezami zmian. Hipoteza pierwsza, j=l, zakłada proporcjonalność zmian z obu procedur do mierzalnych naporów TR i TD). Hipoteza druga, j = 2, zakłada proporcjonalność zmian z obu procedur do mierzalnych mocy PDR i PDD. Rozpatruje się kryteria zmian określane jako Kij. Sformułowano dwa warunki, jakie spełniać winny poszczególne kryteria akceptowalne do stosowania. Stwierdzono, że oba warunki są spełnione, gdy stosuje się kryterium K11 i kryterium K21. Kryteria K13 i K23 spełniają jedynie warunek pierwszy.