Effects of Rudder and Blade Pitch on Hydrodynamic Performance of Marine Propeller Using CFD

In the process of designing a marine propeller, hydroelasticity effects are neglected in most cases, due to the negligible influence of the blade’s deformation on its hydrodynamic characteristics. However, there are cases where the impact of hydroelasticity is crucial, for example in the case of high skew-back propellers or heavy-loaded composite propellers. Furthermore, the importance of composite propellers is growing due to their wide range of application, for instance in naval ships and unmanned vehicles. Although structural models and two-way fluid-structure interactions are implemented in most commercial CFD solvers, their relevance to the design process is severely limited due to the high computational cost for a single iteration. An effective solution would therefore be to implement a two-way fluid-structure interaction model in the lifting surface software, which is commonly accepted as a design tool due to its relatively low computational time and its applicability to multi-criteria optimisation. This paper presents the results of hydrodynamic analyses of an elastic propeller carried out using in-house software based on the lifting surface flow model, and extended with the FEM model for the blade structure. The results are compared with experimental measurements and computational analyses with the commercial RANS solver STAR-CCM+.

Section: Conclusion and Further Workmentioning

confidence: 99%

Experimental Validation of an FEM Model Based on Lifting Theory Applied to Propeller Design Software

Grządziela,

Kraskowski,

Król

et al. 2024

“…As can be observed from the oscillogram in Figure 5, the high critical frequencies of the torque , Ω cr2-1 , Ω cr2-2 and Ω cr2-3 are almost the same. This allows us to conclude that the rotational inertia of displaced water J v has little effect on critical frequencies that occur below the maximum engine speed [27][28][29][30][31].…”

Section: Tms Propulsion System For Various Values Of the Moment J Vmentioning

confidence: 99%

Transfer Function for a Controllable Pitch Propeller with Added Water Mass

Leshchev,

Maslov,

Palagin

et al. 2023

The relevance of this study lies in the fact that it presents a mathematical model of the dynamics of the propulsion system of a ship that takes into consideration the mass of water added to it. The influence of this phenomenon on the resonant frequencies of the propeller shaft is examined, and a transfer function for a controllable-pitch propeller is obtained for various operating modes. The purpose of the study is to improve the calculation of the dynamic operating modes of a controllable-pitch propeller by examining the features of a visual models. The VisSim software package is used in the study. A visual model is developed that considers the influence of the rotational speed on the value of the rotational inertia attached to the variable-pitch screw of the mass of water, and a special transfer function is proposed. The study shows that a transfer function of this type has a loop enabling negative feedback. An analysis of the operation of the propeller shaft at its resonant frequency is conducted based on the application of frequency characteristics using the transfer functions obtained. We show that in the low-frequency region, a consideration of the added rotational inertia using the proposed transfer function leads to a significant difference compared to the result obtained with the existing calculation method.

“…There are also other aspects that are coupled with these interactions: in case of the propeller, cavitations, [3,4], vibrations [5], and tip vortices [6] are phenomena that affect these interactions. The interaction between the propeller and the rudder and the influence of the blade pitch on the hydrodynamic performance of propeller [7] are other aspects that should be mentioned in this regard. Last but not least, the configuration of propeller, for example with or without a Wake-Equalising Duct (WED) [8], changes the performance of the propeller and the interactions mentioned above.…”

Section: Introductionmentioning

confidence: 99%

Impact of Propeller Emergence on Hull, Propeller, Engine, and Fuel Consumption Performance in Regular Head Waves

Ghaemi

Zeraatgar

2022

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.