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Wyszukujesz frazę "Zhang, Yang" wg kryterium: Autor


Wyświetlanie 1-7 z 7
Tytuł:
Evaluation of geometrical influence on the hydrodynamic characteristics and power absorption of vertical axisymmetric Wave Energy Converters in irregular waves
Autorzy:
Zhang, Wanchao
Zhu, Yang
Liu, Shuxu
Wang, Jianhua
Zhang, Wentian
Powiązania:
https://bibliotekanauki.pl/articles/32920981.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
vertical axisymmetric
ring-shaped stepped surface
boundary approximation
constringent
geometrical shape
Opis:
To obtain the mechanical energy of waves from arbitrary directions, the vibration absorbers of wave energy converters (WEC) are usually vertically axisymmetric. In such case, the wave-body interaction hydrodynamics is an essential research topic to obtain high-efficiency wave energy. In this paper, a semi-analytical method of decomposing the complex axisymmetric boundary into several ring-shaped stepped surfaces based upon the boundary approximation method (BAM) is introduced and examined. The hydrodynamic loads and parameters, such as the wave excitation forces, added mass and radiation damping of the vertical axisymmetric oscillating buoys, can then be achieved by using the new boundary discretisation method. The calculations of the wave forces and hydrodynamic coefficients show good convergence with the number of discretisation increases. Comparison between the constringent results and the results of the conventional method also verifies the feasibility of the method. Then, simulations and comparisons of the hydrodynamic forces, motions and wave power conversions of the buoys with series draught and displacement ratios in regular and irregular waves are conducted. The calculation results show that the geometrical shape has a great effect on the hydrodynamic and wave power conversion performance of the absorber. In regular waves, though the concave buoy has the lowest wave conversion efficiency, it has the largest frequency bandwidth for a given draught ratio, while in irregular waves, for a given draught ratio, the truncated cylindrical buoy has the best wave power conversion, and for a given displacement of the buoy, the concave buoy shows the best wave power conversion ability.
Źródło:
Polish Maritime Research; 2023, 2; 130-145
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on striking ship with loading impact on the performance of the double hull oil tanker collision
Autorzy:
Wu, W.
Yang, Y.
Zhang, J.
Lu, J.
Powiązania:
https://bibliotekanauki.pl/articles/258890.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship collision
fluid-structure interaction
impact parameters
numerical simulation
Opis:
Due to the great danger of the collision of oil tankers, lots of research on the collision of oil tankers has been carried out. But, at present, the research on the collision of oil tankers mainly focuses on the loading condition of the struck ship, ignores the impact on the loading condition of the striking ship. However, during the actual oil tanker collision, the striking ship is generally in the state of loading. Therefore, it is necessary to carry out the analysis of the impact of the loading condition of the striking ship on the collision damage of the oil tanker. In this paper, the effect of striking ship with loading on the impact performance of the side structure during the collision of the cargo double hull oil tanker has been investigated. The ship collision model was established by using the finite element software ANSYS/ LS-DYNA which is based on 7000 tons of double hull oil tankers. Based on the analysis of the collision force, impact of striking speed changes, impact of striking deep changes and structural energy absorption during the collision process, the influence of the striking ship with loading on the damage mechanism and the impact performance of the double shell oil ship side structure was expounded. The results show that the influence of the striking ship with loading can be great to the damage to side hull during the research of the collision performance of the oil tanker.
Źródło:
Polish Maritime Research; 2018, S 2; 42-48
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An improved dynamic surface sliding mode method for autonomous cooperative formation control of underactuated USVS with complex marine environment disturbances
Autorzy:
Dong, Zaopeng
Qi, Shijie
Yu, Min
Zhang, Zhengqi
Zhang, Haisheng
Li, Jiakang
Liu, Yang
Powiązania:
https://bibliotekanauki.pl/articles/32909478.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
underactuated USV
dynamic surface sliding mode control
lateral velocity tracking differentiator
nonlinear disturbance observer
Opis:
In this paper, a novel dynamic surface sliding mode control (DSSMC) method, combined with a lateral velocity tracking differentiator (LVTD), is proposed for the cooperative formation control of underactuated unmanned surface vehicles (USVs) exposed to complex marine environment disturbances. Firstly, in view of the kinematic and dynamic models of USVs and the design idea of a virtual control law in a backstepping approach, the trajectory tracking control problem of USVs’ cooperative formation is transformed into a stabilisation problem of the virtual control law of longitudinal and lateral velocities. Then, aiming at the problem of differential explosion caused by repeated derivation in the process of backstepping design, the first-order low-pass filter about the virtual longitudinal velocity and intermediate state quantity of position is constructed to replace differential calculations during the design of the control law, respectively. In order to reduce the steady-state error when stabilising the virtual lateral velocity control law, the integral term is introduced into the design of the sliding mode surface with a lateral velocity error, and then the second-order sliding mode surface with an integral is structured. In addition, due to the problem of controller oscillation and the role of the tracking differentiator (TD) in active disturbance rejection control (ADRC), the LVTD is designed to smooth the state quantity of lateral velocity. Subsequently, based on the dynamic model of USV under complex marine environment disturbances, the nonlinear disturbance observer is designed to observe the disturbances and compensate the control law. Finally, the whole cooperative formation system is proved to be uniformly and ultimately bounded, according to the Lyapunov stability theory, and the stability and validity of the method is also verified by the simulation results.
Źródło:
Polish Maritime Research; 2022, 3; 47-60
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the application of cold energy of largescale LNG-powered container ships to refrigerated containers
Autorzy:
Li, Yajing
Li, Boyang
Deng, Fang
Yang, Qianqian
Zhang, Baoshou
Powiązania:
https://bibliotekanauki.pl/articles/2033271.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
LNG-powered container ship
LNG cold energy utilization
refrigerated container
cold storage
Opis:
With the aim of considering the problem of excess fuel cold energy and excessive power consumption of refrigerated containers on large LNG-powered container ships, a new utilisation method using LNG-fuelled cold energy to cool refrigerated containers in cargo holds is proposed in this study, and the main structure of the cold storage in the method is modelled in three dimensions. Then, combined with the different conditions, 15 different combination schemes of high temperature cold storage and low temperature cold storage are designed to utilise the cold energy of LNG fuel, the exergy efficiency and cold energy utilisation rate calculation model of the system is established. The simulation tool ‘Aspen HYSYS’ is used to simulate and calculate the exergy efficiency and cold energy utilisation rate of the system under 15 combinations, verifying the feasibility of the scheme. According to the characteristics of such a ship’s cross-seasonal navigation routes and the number of refrigerated containers loaded in different ports, the combination schemes of the number of low-temperature cold storage and high-temperature cold storage are selected. Thus, the average exergy efficiency and cold energy utilisation rate of the whole line is obtained, which proves that LNG-powered container ships could effectively utilise the cold energy of LNG. By calculating the total electric energy consumed by refrigerated containers on the whole sailing route, before and after the adoption of the LNG cold energy method, it is found that the adoption of this new method can promote the realisation of energy saving and emission reduction of ships.
Źródło:
Polish Maritime Research; 2021, 4; 107-121
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:
Assisted propulsion device of a semi-submersible ship based on the magnus effect
Autorzy:
Lv, Jingze
Lin, Yiqun
Zhang, Rui
Li, Boyang
Hualin, Yang
Powiązania:
https://bibliotekanauki.pl/articles/32909218.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
Flettner rotor
semi-submersible ship
wind energy
ship propulsion
numerical simulation
Opis:
The purpose of this study is to explore the potentiality of wind propulsion on semi-submersible ships. A new type of Flettner rotor (two rotating cylinders) system installed on a semi-submersible ship is proposed. The structure and installation of two cylinders with a height of 20 m and a diameter of 14 m are introduced. The numerical simulation of the cylinder is carried out in Fluent software. The influence of apparent wind angle and spin ratio on the two cylinders are analysed, when the distance between two cylinders is 3D-13D (D is cylinder diameter). When the distance between two cylinders is 3D, the performance of the system increases with an increase in spin ratio. Moreover, the apparent wind angle also has an effect on the system performance. Specifically, the thrust contribution of the system at the apparent wind angle of 120° is the largest at the spin ratio of 3.0. The maximum thrust reaches 500 kN. When the spin ratio is 2.5 and the apparent wind angle is 120°, the maximum effective power of the system is 1734 kW. In addition, the influence of the two cylinders distance on system performance cannot be ignored. When the distance between the two cylinders is 7D and the spin ratio is 2.5, the effective power of the system reaches a maximum, which is 1932 kW.
Źródło:
Polish Maritime Research; 2022, 3; 33-46
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations of mechanical properties of API P110 steel casing tubes operated in deep-sea sour condensate well conditions
Autorzy:
Yao, Zilin
Wang, Yu
Yang, Xuefeng
Gao, Anping
Zhang, Rong
Jia, Yanjie
Powiązania:
https://bibliotekanauki.pl/articles/1585020.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
deep-sea drilling environment
mechanical properties
yield strength
tensile strength
corrosion modeling
Opis:
Due to the complexity of the marine environment, in deep-sea drilling, all kinds of strings are corroded by different deepsea conditions for a long time, accompanied by high temperature and high pressure, which lead to the continuous change of mechanical properties of materials. In order to solve the problem that the material mechanical parameters cannot be accurately described in the performance analysis of the casing, deep-sea simulated corrosion and material damage experiments of P110 material were carried out in this paper. Mass loss and tensile experiments on corrosion-damaged test pieces were conducted under different corrosion experimental periods. The changes in mechanical properties of the material were analyzed. Equations of the variation of the equivalent yield strength and the equivalent tensile strength were obtained. The results show that the equivalent yield strength and the equivalent tensile strength decrease with the increase of the weight loss rate. Based on the experimental results and finite element analysis, a method for establishing the material corrosion model was proposed in this paper. The deep-sea drilling corrosion performance model of P110 material was established, which greatly reduced the error caused by the material uniformity assumption in finite element analysis. This paper provides a theoretical basis for the analysis of reliability and life of P110 materials in wells.
Źródło:
Polish Maritime Research; 2020, 3; 121-129
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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