Papers by Keyword: Vessel

Abstract: It is natural to define marine corrosion in terms of the different zones in which the corrosion occurs such as atmosphere splash, tidal and sea mud etc. However, this study focused on issues affecting the marine structures, different types of corrosion and their impact on the marine steel structures as well as the machinery/equipment. Furthermore, several control measures of corrosion necessary to avert corrosion in marine environments were discussed. However, it was established that prolonged contact of marine structures with seawater would lead to corrosion as well as ruing the safety elements present. Thus, the study provides potential information to material scientists on the need for using structural steels of adequate mechanical properties.

Abstract: Here, we present a numerical approach to analyze the integrity of a vessel that was subject to a weld repair. A Post-Weld Heat Treatment (PWHT) process was implemented to a vessel undergone weld repair due to leakage. Due to the thick wall of the welded bottom head, this welding process must be followed by the PWHT to relieve the residual stress, as well as to improve the material properties. PWHT process was performed by heating the welded area to reach 675 °C temperature. A numerical approach using finite element analysis (FEA) method was performed to analyze the integrity of the vessel. Based on the analysis, the structure is still stable within the applied load. PWHT process does not lead to buckling on the main structure and the load is still lower than the load required for the occurrence of buckling. A sensitivity analysis was also performed with reduced temperatures to 630 °C or reduction of PWHT area width. These changes were found to have negligible effects in reducing the stress and strains in the vessel. After PWHT is completed, the structure is still considered to be safe to be operated, as indicated by its strain that is still below the allowable strain and only relatively small deflection was occurred.

Abstract: The aim of the paper is to evaluate numerical analysis of the fluid flow during the outflow from vessel orifices at various locations. The problems of the outflow velocities and pressure fields were well-chosen for the given purposes. The selected fluid flow problems were solved by numerical simulation using FEM in ANSYS. For numerical simulation, we used the basic steps to design an abstract model in the ANSYS virtual environment. Numerical simulation requires a geometric model complemented by physical properties of flowing fluids as well as both the initial and boundary conditions. It is then possible to calculate the velocity and pressure fields by numerical simulation for a particular fluid type. The results obtained from the numerical simulation were compared with those of the analytical solution. The results obtained from modeling and numerical simulation correspond to the actual values ​​with minimum deviations. The demonstrated type of the problem solved by numerical simulation and modeling confirmed the advantages and possibilities of flexible solutions for any combination of problems in the field of ​​fluid dynamics. Modeling and numerical simulation of fluid flow can provide results regarding the speed and the pressure fields in vessels and pipelines.

Abstract: Every engine needs a cooling system in order to maintain the performance of engine. In this study the cooling system is applied in naval ship with the exchange of freshwater and seawater. Since the seawater contains biological fouling, then it is scaled in the heat exchanger so that the performance of heat exchanger is decreasing from time to time. This makes the heat transfer rate in cooler is less efficient so that to maintain the BHP of the engine it needs to consume more fuel. The result shows that the effect could incur a loss of about USD 463,852.8/month. This condition makes the importance of cooling system maintenance in order to keep the temperature of the naval ship engine and to minimize the additional fuel cost. For cooling system itself, to keep the cooler in a good condition, it needs to clean the cooler for every 720 hours, or once a month.

Abstract: Energy and environmental problems of the economy in the world, especially in metropolitan areas caused by vehicles, is now becoming important and one of the main ways of solving this problem is using natural gas. Widespread use of gaseous fuel is heavily restricted by its storage problem in container under high pressure (20-25 MPa) in a gas state or at low temperatures (-163 ° C) in a liquid state. And the most promising solution of this problem is to develop a vessel based on of adsorption technology, which is designed for efficient storage of natural gas at moderate pressures (2-3.5 MPa).

Abstract: An ultrasonic Rayleigh wave transducer was designed for nondestructive pressure measurement in vessels. Using polyimide resin as the wedge material, the Rayleigh wave transducer had two piezoelectric elements which were placed in the same wedge with a certain distance. Variations in pressure and temperature of vessels can affect the velocity of ultrasonic waves, which will affect variations in time delay in receiving of the same Rayleigh wave with the two piezoelectric elements of the designed transducer. Based on the acoustoelasticity principle and considered the effect of temperature, a practical correlation model between the time delay and both the pressure and temperature of vessels was developed. Using an air vessel as a specimen, Rayleigh wave transducers were arranged in the axial direction of the vessel. The results of temperature experiments show that effect of changes in temperature on time delay agree with the theoretical results. With the calculation temperature compensation in pressure experiment, the relationship between the variations in the time delay caused by changes of pressure and the pressure is established. The pressure measurement results show that the measurement model is effective and the maximum absolute error is 0.09 MPa, which could be acceptable in engineering application.

Abstract: There are many factors affecting vessels stopping distance and crash stopping distance, and it is very complicated to calculate them accurately. At present there are several calculation methods about them, but all these methods have large error. Based on the research of the existing calculation methods, this paper simplifies vessel resistance and calculates vessels stopping distance and crash stopping distance accurately by means of physical and mathematical methods.

Abstract: A novel method has been proposed for integrated Beidou and GPS (Global Positioning System) navigation system in vessel monitoring system. Application of integrated Beidou and GPS navigation system's high precision positioning and SMS (Short Messaging Service) communication technology in vessel can well solve the problem of vessel navigation, positioning, remote monitoring and commanding. Based on 27 stations of Crustal Moment Observation Network of China, satellite visibility and availability of integrated Beidou and GPS are calculated and analyzed in detail. A data compression algorithm is proposed for Beidou SMS communication technology to get the continuous location and other state of the target vessel. Experimental results reveal that the integrated Beidou and GPS system is superior to any single system in all respects of positioning performance.

Abstract: This paper use the software ANSYS to study the aluminum alloy (LF6) welding residual stress by numerical simulation and experimental study. The result indicates that the aluminum alloy (LF6) has the same residual stress distribution with others, there is a maximum value existing at the range of 4-5mm near the welding seam.

Abstract: The design idea of monitored control subsystem of vessel dynamic cyclone oily water separator is based on LabVIEW software platform, adopted DataSocket technology, by using DAQcard-A-16E-4E data acquisition card to realize real-time monitoring. This paper introduced the components of the monitored control system, analyzed its working conditions. According to the experimental operating records on some real ships, the application results and characteristics are summarized.