Abstract: In this paper, a testing device for gas cylinder, which is composed of PC, data acquisition card on USB bus technology and the application software compiled on the labVIEW platform, is designed on the basis of virtual instrument technology. The assembly and disassembly of the cylinder plug, weighing, temperature measuring, being irrigated upright, and hydraulic pressure testing are all realized. This device has been put into use with highly practical effect.
Abstract: Finite element model of helical gear meshing of large burden marine is built based on explicit dynamics finite element method, dynamics stress variation of helical gear tooth is simulated under multiple working conditions, research is focused on the impact of changes in working conditions on the dynamic stress of the tooth root. The results show that helical gear pair speed and center distance error have great impact on dynamic stress of tooth root. The results provide reference for dynamic performance optimization of marine gears.
Abstract: In this paper, the circuit topology and operating principle of the three level converter Boost converter was modeled, and its working mode was also analyzed, then, a practical circuit was established, through Simulink and experiment, the theoretical analysis result was verified. The hardware and software of the three-level Boost converter adopted modular design, the module function was detected after completing each module design, which has efficiently improved the its efficiency, readability, portability and versatility. The ideal function of the three-level Boost converter was realized, which is easy to control, high-precision, Stable and reliable operation.
Abstract: In order to explore the feasibility of remove agitation in gibbsite precipitation process, computational fluid dynamics method was carried out to study the flow field of sodium aluminate solution slurry in an unagitated precipitation tank. The solid content distribution is investigated by volume fraction of solid phase. The simulation results showed that little difference of solid content is found in the range between the tank bottom and the height position of 25 meters, which is the most zone of the tank, and there is a somewhat large difference in the top 5 meters zone, where the stratification occurs. With the inlet velocity increases, the zone of stratification shrinks to near the tank surface, which makes the solid content distribution in the whole tank seem uniform much more. Therefore, without agitation, the solid content would not concentrate to tank bottom completely in the normal work flow.
Abstract: Introduced the characters of crude oils containing sulfur and naphthenic acid, analyzed the corrosion and safety of this kind of oil acted on refinery equipment, investigated the corrosion on oil atmospheric and vacuum distillation equipment, delayed coking unit and gas desulphurization unit. Tabled a proposal to forecast life of the device using risk based inspection and grey system theory, assured the equipment to run long-term and safety.
Abstract: The main bearing is one of the primary friction pairs of a diesel engine. The lubrication condition affects the performance of the marine diesel engine directly. Continuous working time of main bearings is longer, load is higher and working condition is even worse especially in low medium speed marine diesel engine, making it difficult to form good dynamic pressure lubrication.Therefore, this paper takes a high-power marine diesel G32 with 9 cylinders as an example, calculates and analyzes the load, the orbit of main shaft center and the minimum thickness of oil film in each main bearing, providing the basis to estimate each main bearing’s lubricating condition, predicting each main bearing’s performance precisely and judging whether there exists abnormal working conditions in each main bearing.
Abstract: In order to solve the fight problem of damaged airplane in war, based on linear elasticity, elastoplasticity and net section yield criterion, the calculation model for residual strength of plate with smooth circular hole is founded. Furthermore, the flexibility of calculation models using these three methods is analyzed through examples. All above can be basis for airplane battle damage assessment.
Abstract: In this paper,the fracture process of concrete beam was monitored by acoustic emission,and the acoustic emission signals of the concrete beam in fracture process were transformed by Hilbert-huang,four different failure stages could be seen in the fracture process of concrete beam through the Hilbert spectrum diagram and the effectively monitoring of failure process of concrete beam was realized.
Abstract: Chinas offshore oil and gas has been developed from shallow water to deep water. Subsea production facilities play more and more role in deepwater oil and gas fields, in which Christmas tree is the key equipment to control and regulate the oil well production of deepwater production systems, but it has great installation costs and risk. For complex underwater environment, it is necessary to find a best way to install the Christmas tree securely and rapidly. ROV (Remotely Operated Vehicle) is wildly used in the field of offshore oil, especially in deep water for its large working depth, safe, efficient and other characteristics, and it has become an indispensable tool for development of deep-sea oil and gas. In one Christmas tree installation at Liwan3-1 deepwater oilfield, the ROV succeeded in assisting the installation of Christmas tree. The solutions for winding and wrong operation risk in installation process are given in the end.