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1
Content available Reverse engineering-inspired parametric 3D geometry model of marine propeller
Zheng Long, Chen Shunhuai, Chen Xinyu, Ji Shengchen
Polish Maritime Research
|
2023
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nr 3
35--47
EN
In this study, an effective parametric 3D geometry model of a propeller was established with the aid of reverse engineering. The goal is to reduce the free parameters while automating the modelling of the propeller. The process of building the parametric model begins by generating an initial point cloud by defining the feature matrix associated with the propeller blade profile shape. Subsequently, the initial point cloud is deformed and refined by the deformation feature matrix and resampling. Finally, a 3D geometry model of the propeller is generated by surface reconstruction. The model can be built automatically by interactively modifying the feature matrices. Two numerical analyses illustrate the performance of the parametric 3D geometry model. Specifically, two propellers are constructed using the proposed model to estimate the shape error between the reconstructed propellers and the original offset of the propellers. These propellers are selected as research objects to determine the hydrodynamic performance error between the propeller constructed by the proposed model and a benchmark propeller. According to the results of the numerical study, the parametric 3D geometry model can precisely reconstruct the aforementioned geometry within a valid error range. The hydrodynamic error analysis demonstrates that the geometric inaccuracy from the reconstructed model has less impact on the propeller performance. This indicates that the model described in this study is generalised and robust. Moreover, some uncommon propeller CAD models were generated in batches using the parametric 3D geometry model.
2
Content available Blade cup method for cavitation reduction in marine propellers
Samsul M. Burak
Polish Maritime Research
|
2021
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nr 2
54--62
EN
Energy efficiency has become more important in every industry and daily life. Designing and building a more efficient marine vehicle can lead to lower fuel consumption and a longer lifetime for the components of the vehicle. Erosion caused by cavitation reduces the service life of the propeller and the related components in the propulsion and maneuvering system. Reducing cavitation leads to a longer life for these components. This paper aims to explain and investigate propeller blade cup as a cavitation reduction method for marine propellers. A cavitating no-cup propeller is created and analyzed then the cupped version of this propeller is generated and analyzed to compare with the no-cup propeller. Cavitation results of these propellers are investigated. In addition, the thrust, torque, and efficiency of the propellers are compared.
3
Content available Blade section profile array lifting surface design method for marine screw propeller blade
Król Przemysław
Polish Maritime Research
|
2019
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nr 4
134--141
EN
The lifting surface model is widely used in screw propeller design and analysis applications. It serves as a reliable tool for determination of the propeller blade mean line and pitch distribution. The main idea of this application was to determine the blade shape that would satisfy the kinematic boundary condition on its surface with the prescribed bound circulation distribution over it. In this paper a simplified lifting surface method is presented – in which the 3D task for the entire blade is replaced by a set of 2D tasks for subsequent blade section profiles.
4
Content available Hydrodynamic multidisciplinary optimization of a container ship and its propeller using comprehensive HPSOP code
Zakerdoost H., Ghassemi H.
Zeszyty Naukowe Akademii Morskiej w Szczecinie
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2018
|
nr 53 (125)
48--56
EN
Hydrodynamic shape optimization plays an increasingly important role in the shipping industry. To optimize ship hull and propeller shapes for minimum total (friction+wave) calm-water resistance and maximum open water efficiency, respectively, the main particulars of a hull and propeller model are considered as design variables. The optimization problem is performed by using an integrated hull-propeller system optimization problem (HPSOP) code in a multi-level and multi-point methodology in early-stage ship design. Three numerical methods with variable fidelity are employed to carry out the hydrodynamic performance analysis of a ship’s hull and propeller. A ship and its propeller are selected as initial models to illustrate the effectiveness of the proposed optimization procedure. The numerical results show that the developed technique is efficient and robust for hydrodynamic design problems.
5
Content available Experimental and numerical validation of the improved vortex method applied to CP745 marine propeller model
Król P., Tesch K.
Polish Maritime Research
|
2018
|
nr 2
57--65
EN
The article presents a numerical analysis of the CP745 marine propeller model by means of the improved vortex method and CFD simulations. Both numerical approaches are validated experimentally by comparing with open water characteristics of the propeller. The introduced modification of the vortex method couples the lifting surface approach for the propeller blades and the boundary element method for the hub. What is more, a simple algorithm for determination of the propeller induced advance angles is established. The proposed modifications provide better results than the original version of the vortex method. The accuracy of the improved method becomes comparable to CFD predictions, being at the same time a few hundred times faster than CFD.
6
Content available Comparative analysis of the calculation methods of the marine propeller’s blade thickness
Murawski L.
Journal of KONES
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2018
|
Vol. 25, No. 2
253--260
EN
Strength of the propellers with the skewback greater than 25º has to be numerically analysed according to marine classification societies. The finite element method (FEM) is advised for that kind of calculations. Classical and typical propellers (skewback < 25º) may be designed on the base of empirical equations given by the societies. The minimal thickness of the propeller blade is determined by the equations. Each classification society has their own empirical formula. Sometimes, well-designed propeller for one society has not enough strength according to the other society. What is more, propellers designed according to the empirical formulas might be not optimal. Comparative analysis of the marine propeller’s blade strength has been described in the article. Calculations of the propeller’s blade thickness have been done by two international classification societies’ empirical formulas (ABS and DNV). The results have been compared with Finite Element Method calculations (NASTRAN program). The methodology of propeller static strength vibration analyses is presented. Numerical calculation methodology is based on solidstate mechanics with loadings determined by fluid mechanics calculations. Steady state and transient fluid flow of the propeller’s working conditions were taken into account. In order to determine the optimal modelling method of the propeller several different numerical models were compared, including free model of whole propeller and single blade with boundary conditions placed in the foot. The propeller optimization was the main target of the analyses. Propeller blade thickness might be reduced after FEM method analysis - the propeller mass saving can be achieved.
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