Analysis of Hydrophobic Painting in Model-Scale Marine Propeller

Katsuno, Eduardo Tadashi; Dantas, João Lucas Dozzi; Silva, Emilío Carlos Nelli

doi:10.1115/omae2018-78209

Cited by 5 publications

(3 citation statements)

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“…With a defined method for propeller simulation, a numerical analysis based on RANS CFD software is done to study the behavior of the boundary layer flow with the condition that imposes the low-friction / hydrophobic effect in a fully-covered super-hydrophobic propeller (Katsuno et al, 2018). This section aims to estimate the gain of performance in propellers, guiding the definitions and restrictions that should be looked for the topology optimization.…”

Section: Results Of Hydrophobic Simulationsmentioning

confidence: 99%

Topology optimization of low-friction painting distribution on a marine propeller

Katsuno

Dantas²,

Silva³

2022

Struct Multidisc Optim

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Following the United Nations 2030 Agenda to achieve a better and more sustainable future, there is an interest in new energy efficiency technologies to address emissions from international maritime shipping. A large portion of the available research focused on paints that reduce the fouling and friction of the hulls of these vessels, such as hydrophobic paints. Yet, research applied to propellers is smaller when compared to hulls. Covering the blade surface with hydrophobic paint behavior changes the drag of the propeller and, consequently, the hydrodynamic efficiency. However, covering a blade may adversely affect the flow in certain regions, reducing the propeller performance. This paper studies a practical application of the super-hydrophobic surface (SHS) pattern distribution on a marine propeller using the topology optimization method to determine regions where the application of surface treatment leads to improved propeller efficiency. The numerical method is developed to model the turbulent flow condition with the behavior of the boundary layer that imposes the low-friction/hydrophobicity effect to predict the performance of a coated propeller. To evaluate the proposed method, firstly, a fully covered blade is simulated for several hydrophobic conditions and then the topology optimization is conducted. Despite the SHS behavior being simplified by adopting the slip length model, the obtained optimization results show the regions to be prioritized in order to maximize the hydrodynamic efficiency.

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Section: Results Of Hydrophobic Simulationsmentioning

confidence: 99%

Topology optimization of low-friction painting distribution on a marine propeller

Katsuno

Dantas²,

Silva³

2022

Struct Multidisc Optim

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“…Choi et al [18] used a commercial super-hydrophobic coating on the surface of a 42 mm diameter double-blade propeller and found that the super-hydrophobic coating could reduce the turbulent kinetic energy of the propeller's wake by about 20%. Katsuno et al [19] conducted CFD research on a super-hydrophobic coated propeller and used the concept of boundary layer slip length to simulate the effect of hydrophobic slip. The results showed that the propeller efficiency calculated by this boundary layer hydrophobic model did not increase significantly.…”

Section: Introductionmentioning

confidence: 99%

Performance of a Propeller Coated with Hydrophobic Material

Pan

Zeng

Tian

et al. 2022

JMSE

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Computational and experimental methods were used to study a propeller coated with hydrophobic material and a propeller with a conventional surface for comparison. In CFD simulations, the blade surface mesh was arranged in a way to set non-slip or free slip wall boundary conditions with different proportions to define the level of surface slip. The conventional and the hydrophobic material propellers defined by different surface slip rates were simulated under different advance speed coefficients and different rotational speeds. Propeller performance results, blade pressure, and the Liutex vorticity distribution were studied. An experimental platform was established to study the velocity field around the propeller using a Particle Image Velocimetry (PIV) device. The CFD calculation results were compared with the PIV results. It was found that the calculation results using a 75% surface slip rate were closer to the experimental results. The calculation results show that the propeller coated with hydrophobic material has improved thrust and efficiency compared with the propeller with conventional material. The hydrophobic material can significantly reduce the low-speed region downstream of the propeller hub. The hub and the tip vortices shown by the Liutex are also significantly reduced. Those changes help to improve the propulsion efficiency.

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“…The objective is to analyze the trade-off between the skin-friction drag reduction due to SHS presence, an expected result, and the increase of suction pressure, i.e., reduction of absolute pressure, which may increase the cavitation phenomena. This chapter, published in Katsuno, Dantas and Silva (2018), aims to estimate the gain of performance in propellers, guiding the definitions and restrictions that should be looked for topology optimization, as well as being necessary for a correct definition for the cost function.…”

Section: Experimental Values Comparative and Discussionmentioning

confidence: 99%

Topology optimization of the superficial painting pattern on model-scale propellers applied for hydrodynamic performance.

Katsuno¹

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In the last decades, research was carried out in the investigation of the effects of paintings on the performance of naval vessels. A large proportion of the publicly available research focused on paints that reduce the fouling and friction coefficient of the hulls of these vessels, such as hydrophobic paints. However, research applied to propellers is scarce. Covering the blade surface with paint exhibiting hydrophobic behavior changes the drag of the blades and, consequently, the torque required by the propeller. However, covering a blade fully can adversely affect the flow in certain regions, reducing the performance of the propeller or inducing cavitation inception. This project studies the distribution pattern of the super-hydrophobic surface (SHS) paint on model-scale propellers using the topology optimization method to determine regions where the application of surface treatment leads to improved propeller performance. Propeller simulations were carried out with full turbulent analysis using Reynolds-Averaged Navier-Stokes equations. The numerical method is developed to model the behavior of the boundary layer with boundary conditions that impose the low friction/hydrophobicity effect to predict the performance of a coated propeller. To obtain the topology optimization sensitivities, the discrete adjoint method of the Navier-Stokes equations with the hydrophobic model based on the slip length is studied. The numerical implementation is done by using the Star-CCM+ as the Computational Fluid Dynamics (CFD) software, based on the Finite Volume Method (FVM) as the primal and the adjoint solver, and Interior Point Optimizer (IPOPT) as the optimizer. Derivation of the discrete adjoint problem applied to super-hydrophobic modeling is shown. The application of topology optimization to the hydrophobic distribution on a two-dimensional cases are demonstrated (using internal and external flow as test cases), and for a threedimensional case (propeller). Despite that the SHS behavior is simplified by adopting the slip length model, the obtained results show that regions to be prioritized in order to reduce the dissipated energy is not always intuitive. Furthermore, depending on the operating condition, a fully-SHS case may not be the best option. The novel application of fluid Topology Optimization can be extended for other applications, such as problems of surface design.

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Analysis of Hydrophobic Painting in Model-Scale Marine Propeller

Cited by 5 publications

References 0 publications

Topology optimization of low-friction painting distribution on a marine propeller

Topology optimization of low-friction painting distribution on a marine propeller

Performance of a Propeller Coated with Hydrophobic Material

Topology optimization of the superficial painting pattern on model-scale propellers applied for hydrodynamic performance.

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