Time filter

Source Type

Wu S.,Wuhan Rules and Research Institute of China Classification Society | Wu S.,Wuhan University of Technology | Luo X.,Wuhan Rules and Research Institute of China Classification Society | Fan H.,Wuhan Rules and Research Institute of China Classification Society | Zhang R.,China National Offshore Oil Corporation
Natural Gas Industry | Year: 2015

At the pilot stage, tank trucks are generally used to refuel small LNG-fuelled ships. In this paper, an LNG-fuelled tug boat was selected to evaluate the risks related with the refuelling operation of LNG tank trucks at docks. Firstly, the main risk sources in the process of refuelling were identified on the basis of actual refuelling system and operation conditions. Then, event tree analysis was conducted on the disasters caused by LNG leakage, and the occurrence probability and mortality probability of dangerous scenarios were proposed. Secondly, LNG continuous leakage rate was calculated by using Bernoulli's equation and hydrologic data at the refuelling docks was collected. And thirdly, leakage consequences (e.g. low-temperature heavy gas diffusion and fire) were simulated by using FLACS (3D computational fluid dynamics), and individual risk value in various dangerous scenarios was calculated. Based on an individual risk acceptance criteria, the individual risk value is generally acceptable when LNG-fuelled tug boats are refueled by tank trucks at docks. In the process of refuelling, however, attention should be paid to the following aspects. First, the minimum safety distance during refuelling is 89 m, and ignition source should be prohibited in the zone. Second, the coverage of pool fire in drip tray is 13 m, and personnel should avoid staying in the area if possible. And third, hoses, valves and connectors tend to break during refuelling, so safety measures should be reinforced. © 2015, Natural Gas Industry Journal Agency. All right reserved.


Fan H.,Wuhan Rules and Research Institute of China Classification Society | Wang J.,GUODIAN United Power Technology Inc. | Jin Q.,Wuhan Rules and Research Institute of China Classification Society | Jin J.,Wuhan Rules and Research Institute of China Classification Society
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2012

To assess fatigue strength of a foundation-tube tower transitional ring's reinforced hole detail which is a rolled steel structure, a simplified fatigue analysis approach according to CCS specification was adopted. The normal stress and shear stress S-N curve was synthesized conservatively by considering the aspect of load characteristic, static strength of raw material, fatigue notch factor (FNF), size effects and integrated surface effect factor (ISEF), and then the synthetic S-N curve was reduced and modified according to survival probability, corrosion environment and the damage contribution of low stress range. The equivalent stress range, calculated from equivalent constant-amplitude load, was used to assess fatigue strength based on modified S-N curve. The results showed that FNF and SEF are the main influence factors of S-N curve's synthesizing process, the relative stress gradient (RSG) of the stress distribution should be based on fitted polynomial curve, the components values of the ISEF should be based on the actual situation. According to the S-N curve, the maximal cumulative damage in design life is 0.042.


Chen Q.,Huazhong University of Science and Technology | Ye H.,Huazhong University of Science and Technology | Yang X.,China Ship Development And Design Center | Wang X.,Wuhan Rules and Research Institute of China Classification Society
Huazhong Keji Daxue Xuebao (Ziran Kexue Ban)/Journal of Huazhong University of Science and Technology (Natural Science Edition) | Year: 2011

Unsteady panel method based on the Green's theorem was developed for the hydrodynamic analysis of a three-dimensional oscillating hydrofoil moving near the free surface in the time domain. The Rankine sources and dipoles were distributed on boundary surfaces including the hydrofoil body surface and free surface. The dipoles were also placed on the wake surface and the Kutta condition was satisfied. A time-stepping panel method was employed. The numerical results of thrust force, lifting force and wave patterns were presented for the three-dimensional oscillating hydrofoil. The computed results were compared with other methods, and which verifies the effectively of the presented time-domain algorithm.


Luo X.,Wuhan Rules and Research Institute of China Classification Society | Fan H.,Wuhan Rules and Research Institute of China Classification Society | Zhang H.,Wuhan Rules and Research Institute of China Classification Society | Gan S.,Wuhan Rules and Research Institute of China Classification Society | Liu D.,Zhangjiagang CIMC Sanctum Cryogenic Equipment Co.
Ship Building of China | Year: 2014

A new type of onboard LNG drip tray with foam glass blocks as thermal insulation layer was designed. In order to have a full picture of the thermal insulation performance, a set of experiments was conducted. Liquid nitrogen (LN2) was used as a safer analogue of LNG. To verify the feasibility in using LN2, the vaporization characteristics of LNG and LN2 was compared in same environmental conditions. The results showed that the vaporization rate of LNG was lower than of LN2, but the change of temperature and vaporization rate of LNG is quite different from that of LN2. According to the phenomenon in the experiment, vaporization characteristics of LNG were analyzed, and the feasibility of using LN2 in place of LNG was proved. Two models were designed, and corresponding thermal insulation performance experiments were conducted. The insulation layer thickness of the model 1 was 50 cm, and that of model 2 was 30 cm. Calculations of convective heat transfer showed that both models could meet thermal insulation requirement. For model 1, the experiment duration was about 14 h, and for model 2, the experiment duration was approximately 23 h. Experiments results showed that both models could meet thermal insulation requirement. The model 2 with a thin insulating layer (30 cm) were recommended, but special laying requirements of the foam glass blocks should be considered.


Tu H.,Wuhan Rules and Research Institute of China Classification Society
International Journal of Computer Applications in Technology | Year: 2016

In this paper, the investigation of the performance and emission parameters of a container ship propulsion system is carried out by using a model implemented in Matlab/Simulink environment. The ship propulsion system model is developed in a modular approach and composed of sub-models representing the diesel engine, the shaft system, the propeller and the ship, respectively. Initially, the engine model is validated using the experimental data. Then, simulation of the ship propulsion system at steady state operating points on various resistance curves is performed. The variation of the propulsion system performance and emission parameters over the ship operating range is presented and discussed. Finally, the application of the derived results is exemplified in the case of the speed optimisation for the container ship operating in a specific route in order to minimise the fuel consumption and emissions. Copyright © 2016 Inderscience Enterprises Ltd.


Fan H.,Wuhan Rules and Research Institute of China Classification Society | Jin Q.,Wuhan Rules and Research Institute of China Classification Society | Pan W.,Wuhan Rules and Research Institute of China Classification Society | Liu T.,Wuhan Rules and Research Institute of China Classification Society
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2013

In order to assess how the higher modes influence tower's response, four wind turbines of different size and natural period were selected to provide a systematic view. The 3-dimension FEM models were created, the tower was modeled as lumped mass and beam element, the blades, nacelle and hub were modeled as a lumped mass along with mass moment of inertia. Then, the seismic response of four models which were subjected to two historical earthquake records was investigated based on mode decomposition method. In calculating process, structural damping including aerodynamic damping were taken into account by using Rayleigh damping hypothesis, and according to exist research, two specified damping ratio which can be used to determine the coefficients of Rayleigh damping were set to 0.5% conservatively. In addition, the time-history results of single mass oscillator model recommended by IEC specification and DNV/Risø guideline were compared with lumped mass model adopted by this paper. The study showed that wind turbine tower's seismic response is significant; How the higher modes contribute to towers' response depends on structural dynamic characteristics and the selection of seismic waves; The higher modes contribute a little to displacement and acceleration response, and have some influence on bending moment response, however, play an important role in shear force response; Simplified model of single mass oscillator will be unsafe in time-history analysis.

Loading Wuhan Rules and Research Institute of China Classification Society collaborators
Loading Wuhan Rules and Research Institute of China Classification Society collaborators