Hydrodynamic State of Art Review: Rotor – Stator Marine Propulsor Systems Design

The design of lifting blade shapes is a key engineering application, especially in domains such as those of marine propellers, hydrofoils, and tidal energy converters. In particular, the excitation frequency must be different from that of the structure to avoid resonance. The natural frequency in the cases where the fluid–structure interaction (FSI) is considerably different if considering the coupling added mass (AM) of the water. In this study, vibration experiments were performed using a real propeller in air and water. The modal parameters, natural frequencies, and mode shapes were determined. Validations were performed using 3D solid and acoustic elements in a direct coupling finite element format. The modal results and AM ratios were in agreement with the experimental results. Convenient application and high efficiency are basic requirements for an engineering application. Therefore, an empirical formula was established for the first-order FSI natural frequency to enable rapid estimation, thereby satisfying this requirement.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fluid–Structure Interaction Vibration Experiments and Numerical Verification of a Real Marine Propeller

Lou

Cui

2021

“…Such a solution is not always optimal, since there is a discrepancy between the specified calculated frequencies and the actual ones, especially at low angular speeds of rotation. This means that when calculating the dynamic modes of operation of the propulsion system of a ship, it is necessary to use techniques based on a simplification of the physical process, as reported in [1][2][3][4][5].…”

Section: Introductionmentioning

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.

“…The simplicity of production is a further factor supporting this criterion. For small boats, there is likely to be a need to manufacture a series of consecutively dimensioned propellers prepared to fit the corresponding power packs [2]. This approach also lowers costs, and means that production is fast and cheap.…”

mentioning

confidence: 99%

Design and Operational Diagnostics of Marine Propellers Made of Polymer Materials

Kluczyk

Grządziela

Batur

2022

There has been a rapidly growing interest in the use of composite and polymer materials for the construction of marine propellers for over 20 years. The main advantages of these materials are a reduction in the weight of the propeller, increased efficiency due to the hydroelasticity effect, a reduction of the hydroacoustic signature, and a cost reduction for serial production. This paper presents an overview of diagnostic methods that can be applied at the design level and during the operation of marine propellers made of polymeric materials. Non-invasive contact and non-contact-based diagnostic techniques for evaluating the technical state of the propeller are reviewed, and the advantages and disadvantages of qualitative and quantitative methods are identified. Operational diagnostic procedures for propellers are areessential for the safety of vessels at sea. Finally, the structure of a diagnostic system is proposed. It combined diagnosis process with the genesis of damage and the prognosis of the technical condition, i.e. production and in-service diagnostics.