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Wyszukujesz frazę "CFD" wg kryterium: Temat


Tytuł:
Three-dimensional cfd analysis to study the thrust and efficiency of a biologicallyinspired marine propulsor
Autorzy:
Lamas, M. I.
Rodríguez, J. D.
Rodríguez, C. G.
González, P. B.
Powiązania:
https://bibliotekanauki.pl/articles/259319.pdf
Data publikacji:
2011
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
fish swimming
marine propulsion
undulating fin
biomimetic
computational fluid dynamics (CFD)
CFD
Opis:
Aquatic animals, which are the result of many millions of years of evolutionary optimization, are very quick, efficient, robust, and versatile. Accordingly, biologically-inspired mechanisms which emulate the movement of animals have recently become very popular. For the efficient design of a propulsion system it is very important to analyze the fluid flow in detail. CFD (Computational Fluid Dynamics) has become a powerful technique to understand the phenomena because it gives extensive information about the fluid flow characteristics. In the present work, a propulsion system consisting of an undulating fin which emulates the fish swimming was built. In order to optimize the mechanism, several undulating configurations were studied using a 3D turbulent CFD model. The thrust, drag, efficiency and hydrodynamic characteristics were analyzed. Furthermore, it was shown that the efficiency and thrust depend strongly on the oscillation frequency, amplitude and wavelength. In order to validate this CFD model, the numerically obtained thrust was successfully compared with experimental results from the laboratory mechanism.
Źródło:
Polish Maritime Research; 2011, 1; 10-16
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of rudder and blade pitch on hydrodynamic performance of marine propeller using CFD
Autorzy:
Quang, Pham Ky
Hung, Phan Van
Cong, Nguyen Chi
Tung, Trinh Xuan
Powiązania:
https://bibliotekanauki.pl/articles/32899108.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
rudder
blade pitch
propeller
CFD
Opis:
The use of computational fluid dynamics (CFD) to predict internal and external flows has risen dramatically in the past decade. This research aims to use the commercial software, ANSYS Fluent V.14.5, to illustrate the effects of the rudder and blade pitch on the hydrodynamic performance of the marine propeller by experimenting with propellers and rudders of the M/V Tan Cang Foundation ship, which has designed conditions as follows: diameter of 3.65 m; speed of 200 rpm; average pitch of 2.459 m; boss ratio of 0.1730. Using CFD, the characteristic curves of the marine propeller and some important results showed that the maximum efficiency of the propeller is 0.66 with the open water propeller and 0.689 with the rudder‒propeller system at the advance ratio of 0.6. The obtained outcomes of this research are a significant foundation to calculate and design an innovative kind of propulsion for ships with high performance.
Źródło:
Polish Maritime Research; 2022, 2; 55-63
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical model of so2 scrubbing with seawater applied to marine engines
Autorzy:
Lamas, M. I.
Rodríguez, C. G.
Rodríguez, J. D.
Telmo, J.
Powiązania:
https://bibliotekanauki.pl/articles/258856.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
sulphur dioxide
SO2
scrubbers
CFD
Opis:
The present paper proposes a CFD model to study sulphur dioxide (SO2) absorption in seawater. The focus is on the treatment of marine diesel engine exhaust gas. Both seawater and distilled water were compared to analyze the effect of seawater alkalinity. The results indicate that seawater is more appropriate than distilled water due to its alkalinity, obtaining almost 100% cleaning efficiency for the conditions analyzed. This SO2 reduction meets the limits of SOx emission control areas (SECA) when operating on heavy fuel oil. These numerical simulations were satisfactory validated with experimental tests. Such data are essential in designing seawater scrubbers and judging the operating cost of seawater scrubbing compared to alternative fuels.
Źródło:
Polish Maritime Research; 2016, 2; 42-47
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A hydrodynamic methodology and CFD analysis for performance prediction of stepped planing hulls
Autorzy:
Ghassemi, H.
Kamarlouei, M.
Veysi, S. T. G.
Powiązania:
https://bibliotekanauki.pl/articles/260311.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
planing hull
Hydrodynamic performance
CFD analyzed
Opis:
Nowadays all efforts in planing hull research are focused on resistance reduction for achieving the highest speed in fast planing crafts. Furthermore, many fruitful research projects have been carried out on marine coatings, planning equipment, and optimization of propeller and hull form, which revolutionized industry of high - speed crafts and made them an efficient survival vehicle in coastal areas and rivers. In this paper the hydrodynamic performance of planing hulls are investigated by means of a modified Savitsky model for both non-stepped and stepped bodies. Meanwhile, in order to meet this goal reasonably, effective geometrical parameters of planing hull are investigated and then operational hydrodynamic characteristics of the craft are predicted by using a computational program. Finally, the calculation results are verified by means of a CFD- analysis model.
Źródło:
Polish Maritime Research; 2015, 2; 23-31
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulations of hydrodynamic open-water characteristics of a ship propeller
Autorzy:
Felicjancik, J.
Kowalczyk, S.
Felicjancik, K.
Kawecki, K.
Powiązania:
https://bibliotekanauki.pl/articles/258544.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
CFD
model tests
POW Test
propeller
validation
Opis:
The paper presents the results of numerical simulations of ship propeller operation bearing the name of Propeller Open Water (POW) Tests. The object of tests was a sample ship propeller (PPTC1), the geometrical and kinematic data of which are available, along with the results of model tests, on the official page of the research centre involved in the measurements. The research aimed at verifying the correctness of results of numerical simulations performed in the model and real scale. The results of numerical analyses performed in the model scale were confronted with those measured in the experiment. Then, making use of dimensionless coefficients which characterise propeller’s operation, the recorded model data were extrapolated to real conditions and compared with corresponding results of simulations. Both the numerical simulations and the experimental research were performed for the same propeller load states. The reported research is in line with other activities which aim at developing advanced numerical methods to.
Źródło:
Polish Maritime Research; 2016, 4; 16-22
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical study of the ejection cooling mechanism of ventilation for a marine gas turbine enclosure
Autorzy:
Shi, Hong
Zhang, Qianwei
Liu, Meinan
Yang, Kaijie
Yuan, Jie
Powiązania:
https://bibliotekanauki.pl/articles/32908258.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
gas turbine enclosure
ejecting cooling
ventilation
CFD
Opis:
A marine gas turbine enclosure must be designed to prevent overheating of the electrical and engine control components as well as diluting potential fuel leaks. In order to achieve an optimal enclosure design, a numerical study of the ventilation-ejection cooling mechanism of a gas turbine enclosure is carried out in this paper. The evaluation index of the ejection cooling performance is first proposed and the algorithm of numerical simulation is verified. On this basis, orthogonal combinations of structural parameters are carried out for the expansion angle α of the lobed nozzle and the spacing S between the outlet plane of the lobed nozzle and the inlet plane of the mixing tube. The flow and the temperature distribution inside the enclosure are analysed under different operating conditions. The results show that the influence of the lobed nozzle expansion angle α and the spacing S on the performance is not a single-valued function but the two influencing factors are mutually constrained and influenced by each other. For any spacing, the combined coefficient is optimal for the expansion angle α = 30°. When the expansion angle α = 45° and the spacing S = 100 mm, the combined coefficient and the temperature distribution inside the enclosure are optimal at the same time.
Źródło:
Polish Maritime Research; 2022, 3; 119-127
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrodynamic Analysis of Trimaran Vessels
Autorzy:
Javanmardi, M. R.
Jahanbakhsh, E.
Seif, M. S.
Sayyaadi, H.
Powiązania:
https://bibliotekanauki.pl/articles/258654.pdf
Data publikacji:
2008
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
trimaran
resistance
maneuvering
computational fluid dynamics (CFD)
Opis:
Trimaran vessels are developed for different applications and hydrodynamic behavior of such vessels is different than usual mono-hulls. In this paper hydrodynamic resistance and maneuvering of a trimaran with Wigley body form are investigated. The effects of outriggers position in four different longitudinal and two transverse locations are studied. For hydrodynamic simulations a CFD code has been developed and used. This code is capable for simulating three dimensional, time dependent, two phases, viscous flow coupled with rigid body motion. Formulation and solution algorithm are described in detail. Different case studies have been performance and numerical results have shown good agreement with experimental data. Based on resistance and maneuvering simulation of the trimaran vessels different conclusion are made. The results show that positions of outriggers have great effect on resistance and maneuverability of trimaran. The present method can be further employed to investigate other hydrodynamic qualities of trimaran vessels.
Źródło:
Polish Maritime Research; 2008, 1; 11-18
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Manoeuvring prediction of KVLCC2 with hydrodynamic derivatives generated by a virtual captive model test
Autorzy:
Dai, Kun
Li, Yunbo
Powiązania:
https://bibliotekanauki.pl/articles/258850.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
MMG model
KVLCC2
CFD
manoeuvring prediction
Opis:
This paper describes the application of computational fluid dynamics rather than a towing tank test for the prediction of hydrodynamic derivatives using a RANS-based solver. Virtual captive model tests are conducted, including an oblique towing test and circular motion test for a bare model scale KVLCC2 hull, to obtain linear and nonlinear hydrodynamic derivatives in the 3rd-order MMG model. A static drift test is used in a convergence study to verify the numerical accuracy. The computed hydrodynamic forces and derivatives are compared with the available captive model test data, showing good agreement overall. Simulations of standard turning and zigzag manoeuvres are carried out with the computed hydrodynamic derivatives and are compared with available experimental data. The results show an acceptable level of prediction accuracy, indicating that the proposed method is capable of predicting manoeuvring motions.
Źródło:
Polish Maritime Research; 2019, 4; 16-26
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wake-blade interaction in steam turbine stages
Autorzy:
Świrydczuk, J.
Powiązania:
https://bibliotekanauki.pl/articles/258600.pdf
Data publikacji:
2013
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
turbine passage
secondary vortices
stochastic behaviour
CFD calculations
Opis:
The article discusses the phenomenon of stator Wake/Rotor cascade (W/R) interaction in a steam turbine stage, and the ability to capture it in turbine stage design calculations making use of standard numerical codes. Firstly, the W/R interaction is analysed by comparing its real, experimentally recorded course with the numerical results obtained using vortex theory models and methods. This part of the analysis ends with formulating a conclusion about stochastic nature of the W/R interaction and indicating its reason, which is the vortex structure of the stator wake. Next, a question is discussed whether and how this stochastic nature of the examined phenomenon can be taken into account in calculations of Reynolds Averaged Navier-Stokes (RANS) equations. Differences are indicated between the uniform pattern of the stator wake obtained using a RANS code and the vortex structure of the real wake. It is concluded, however, that despite these differences the RANS results correctly reflect the time-averaged course of the real W/R interaction, and the process of averaging the flow parameters on the sliding plane between stator and rotor calculation areas can be treated as sort of “numerical averaging” of different realisations of the W/R interaction.
Źródło:
Polish Maritime Research; 2013, 2; 30-40
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modified pid control design for roll fin actuator of nonlinear modelling of the fishing boat
Autorzy:
Alarçin, F.
Demirel, H.
Su, M. E.
Yurtseven, A.
Powiązania:
https://bibliotekanauki.pl/articles/258902.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
stability analyses
nonlinear roll motion
modified PID
CFD
Opis:
This study aims to reduce roll motion of a fishing boat which arises from disturbing hydrodynamic effects by means of fin roll stabilizer. It is assured that roll motion with nonlinear damping and restoring moment coefficients are down to the desired level through classical PID and modified PID algorithms. At the time of sailing, stability, a very important concept, was examined using Lyapunov direct method taking initial conditions into consideration, and it was noted that the system was generally stable. In addition, NACA 0015 model was used for the fin roll stabilizer, and flow analysis was carried out with Computational Fluid Dynamics (CFD) method. In the simulation results, when the same gains were used, modified PID controller algorithms were relatively more effective compared to PID in the fin roll stabilizer system.
Źródło:
Polish Maritime Research; 2014, 1; 3-8
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical model to study the combustion process and emissions in the Wartsila 6L 46 four-stroke marine engine
Autorzy:
Lamas, M. I.
Rodriguez, C. G.
Powiązania:
https://bibliotekanauki.pl/articles/259746.pdf
Data publikacji:
2013
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
marine engine
emissions
combustion
CFD Computational Fluid Dynamics
Opis:
The aim of the present paper is to develop a computational fluid dynamics (CFD) analysis to study the combustion process in a four-stroke marine diesel engine, the Wärtsilä 6L 46. The motivation comes from the importance of emissions from marine engines in the global emissions, particularly for nitrogen oxides (NOx) and sulfur oxides (SOx). The pressure and temperature fields were obtained, as well as the exhaust gas composition. In order to validate this work, the numerical results were satisfactory compared with experimental ones, which indicates that this model is accurate enough to reproduce the fluid pattern inside the cylinder during the combustion process. Accordingly, the aim of future works is to use this numerical procedure to optimize the performance and reduce the emissions of the new marine engine designs.
Źródło:
Polish Maritime Research; 2013, 2; 61-66
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CFD modeling of syngas combustion and emissions for marine gas turbine applications
Autorzy:
Ammar, N. R.
Farag, A. I.
Powiązania:
https://bibliotekanauki.pl/articles/259882.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
CFD
syngas fuel
combustion characteristics
exhaust gas emissions
Opis:
Strong restrictions on emissions from marine power plants will probably be adopted in the near future. One of the measures which can be considered to reduce exhaust gases emissions is the use of alternative fuels. Synthesis gases are considered competitive renewable gaseous fuels which can be used in marine gas turbines for both propulsion and electric power generation on ships. The paper analyses combustion and emission characteristics of syngas fuel in marine gas turbines. Syngas fuel is burned in a gas turbine can combustor. The gas turbine can combustor with swirl is designed to burn the fuel efficiently and reduce the emissions. The analysis is performed numerically using the computational fluid dynamics code ANSYS FLUENT. Different operating conditions are considered within the numerical runs. The obtained numerical results are compared with experimental data and satisfactory agreement is obtained. The effect of syngas fuel composition and the swirl number values on temperature contours, and exhaust gas species concentrations are presented in this paper. The results show an increase of peak flame temperature for the syngas compared to natural gas fuel combustion at the same operating conditions while the NO emission becomes lower. In addition, lower CO2 emissions and increased CO emissions at the combustor exit are obtained for the syngas, compared to the natural gas fuel.
Źródło:
Polish Maritime Research; 2016, 3; 39-49
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CFD optimisation of the longitudinal volume distribution of a ship’s hull by constrained transformation of the sectional area curve
Autorzy:
Kraskowski, Marek
Powiązania:
https://bibliotekanauki.pl/articles/32906720.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
parametric optimisation
CFD
model tests
resistance
wave pattern
Opis:
The paper presents a proposal for a formalised approach to hull shape optimisation with respect to total resistance, by fine-tuning longitudinal volume distribution. An algorithm for automated modification of the hull is presented, allowing for varying the sectional area distribution with a negligible influence on the resulting displacement. Computational fluid dynamics (CFD) solver STAR-CCM+ and computer computer-aided design (CAD) software NX were used to search the optimal volume distribution of selected parent shapes, with respect to total resistance. The bow part and the aft part were optimised separately. The resulting resistances of the selected optimal shapes were then verified by means of scale model tests, realised in the towing tank at the Maritime Advanced Research Centre (CTO) S.A. A noticeable gain in total resistance was achieved and confirmed by experimental tests. The proposed approach seems to be a promising method for relatively quick parametric optimisation of the designed hull shapes; it is also applicable for generic CFD optimisation studies.
Źródło:
Polish Maritime Research; 2022, 3; 11-20
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A complete design of ship propellers using the new computer system
Autorzy:
Koronowicz, T.
Krzemianowski, Z.
Tuszkowska, T.
Szantyr, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/258618.pdf
Data publikacji:
2009
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship propellers
design methods
computational fluid dynamics (CFD)
Opis:
The computer system presented in this article is composed of several program blocks for the complete design of ship propellers. The design calculations are based on a combination of the modified lifting line theory and on the vortex lifting surface theory. The system enables solution of the following design problems: - calculation of the scale effect on the ship wake velocity field, including the influence of the propeller and rudder on this field at the propeller location - maximization of the propulsive efficiency - optimization of the propeller blade geometry on the basis of the compromise between the cavitation and blade strength requirements - optimization of the number of propeller blades and blade geometry on the basis of the acceptable level of induced pressure pulses and unsteady shaft bearing forces - calculation of the blade spindle torque for the controllable pitch propellers. The computer system is equipped with many numerical options for graphical visualization of the input data, including an easy possibility of their correction and control of the intermediate and final results of calculations.
Źródło:
Polish Maritime Research; 2009, 1; 29-34
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on hydrodynamic properties of annular cavitator with water injection
Autorzy:
Jiang, Zhenyu
Xiang, Min
Lin, Mingdong
Zhang, Weihua
Zhang, Shuai
Powiązania:
https://bibliotekanauki.pl/articles/259874.pdf
Data publikacji:
2012
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
computation fluid dynamics (CFD)
annular cavitator
water injection
Opis:
Annular cavitator with water injection is one of the key parts of the long-range supercavitating vehicle powered by water ramjet. In this paper, hydrodynamic properties of annular cavitator are studied numerically. The standard k ~ ĺ turbulence model is coupled with the Reynolds Averaged Navier-Stokes (RANS) equations to model the natural supercavitation process. The multiphase flow is considered as a mixture of varying density and modeled by the mass exchange equations. To fully understand this process, numerical simulations were performed for different annular cavitators. Computational Fluid Dynamics (CFD) results, including the pressure distribution and forces acting on the cavitator surface, mass flow and pressure loss of water injection, various supercavity sizes, were obtained and analyzed. The pressure distribution on the cavitator surface was significantly changed which resulted in 4 ~ 6% increase of the total drag of the vehicle. The results show that the mass flow and velocity of the injection water is mainly dependent on the tube size, while the total pressure loss of the water injection is mostly related to the outlet pressure. Supercavity generated by annular cavitator is smaller than that of the discal one. Based on the correlation analysis of the supercavity size and other factors, it could be concluded that the contraction of the cavity size is mainly caused by the diffluent mass flow of the water injection.
Źródło:
Polish Maritime Research; 2012, 4; 11-14
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł

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