Advanced Materials Research Vols. 201-203

Abstract: Nozzle is an important part of oil-air lubrication system. This paper uses Computational Fluid Dynamics (CFD) software FLUENT to study the flow field of oil air, and different air pressure and nozzle throat size are discussed. The results show that: When air pressure is increased from 0.05Mpa to 0.1Mpa, the maximum diameter (2mm) percentage reduces, but the diameters distribution is almost unchanged as the air pressure is increased to 0.3MPa. The throat diameter is decreased, the mean Sauter diameter of oil drop reduces. This paper will provide a theoretical basis for oil-air lubrication nozzle design and selection.

Abstract: In view of the deficiency in calculation precision of turbine diameter at present, the mathematics model of energy distribution on swept area of the down wind turbine was proposed, and the energy expression that taked into account wind shear and tower shade effect was also accurately deduced.Combining with the concrete case, three different calculation methods about turbine dimeter were respectively solved.The calculation results show that the influence of wind shear is really little in turbine diameter calculation.The influentce of tower shade effect is obvious,while the influence of tower height is maximal. There is approximately a linear relationship between the turbine diameter and the tower diameter. The tower height has the maximum. There is a optimum match relationship that satisfies the demand of energy output in the down wind turbine.

Abstract: In the past 20 years, coal bed methane (CBM) surface well technology has made some progress in mining active areas in China, but it still remains at its experimental and study stage, and industrialized and large-scale development has not been achieved. The research of the key technologies, such as the distribution of surface wells, the identification and protection of the high-risk locations of casing damage, the optimization of well structure, and the security monitoring of surface drainage in mining active areas, is the key for CBM surface well development in mining active areas of China.

Abstract: Multi-objective evaluation mode is used in manufacturing system all the time, and this would lead to evaluation complexity and subjectivity when objective number increases. Hence, enterprise profit- oriented single-objective is proposed and created. Then three profit structure elements: sales volume, price and cost as well as their influencing factors are analyzed, and "profit-elements(-properties)-scheme" is created. With this model, environment properties scheme is decided to verify its validity and operation simplicity.

Abstract: In the design of gravel packing sand control, the reasonable selection of gravel size is one of the keys to implementing sand control measures successfully. Aiming at the defects of commonly used methods of gravel size design and the characteristic that the gravel used in field operation is actually a mixture of gravel with multiple grain diameters, this paper builds a model of pore structure in gravel layer through researching the gravel pack structure caused by the gravel of two grain diameters mixed under actual packing conditions, calculates and analyzes the pore sizes in gravel layer. Ultimately, based on Saucier method, this paper presents a new gravel size optimization idea for gravel packing sand control with multiple grain diameters mixed, which agrees with the actual situation of industrial gravel, and gives the idea’s computing method. Considering the ideality of the model in this paper, the author has modified the computing method to make it more fit for the actual packing situation. This gravel size design method also gives consideration to the impact of formation sand uniformity on sand control effect, so it have the characteristics of good practicability, wide applicability and more accurate than other conventional methods.

Abstract: The service-oriented manufacturing is a new advanced manufacturing model, which combines service and manufacturing intensively. Firstly, this paper elaborates the origin of service-oriented manufacturing and the concept of “product system”. Then, it analyzes the characters and value of service-oriented manufacturing. At last, several key directions of future research in service-oriented manufacturing are proposed.

Abstract: Based on the theory of porous flow, a study on prediction of water breakthrough time of horizontal wells in a homogeneous gas reservoir with bottom water is presented. This paper derives water breakthrough time formula of horizontal wells in a reservoir with bottom water drive. In the formula many factors are taken into account, such as height of water avoidance, gas-water mobility ratio, irreducible water saturation, residual gas saturation, etc. Case study indicates that for a horizontal gas well with constant production rate, the water breakthrough time is proportional to the height of water avoidance.

Abstract: Porous media containing water is the prerequisite of existence of threshold pressure gradient (TPG) for gas flow. Based on theory of fluid mechanics in porous medium considering TPG, the non-Darcy flow mathematical model is established for formation pressure analysis of water-bearing tight gas reservoirs. It could provide semi-analytic solution of unsteady radial non-Darcy flow. According to the solution of unsteady radial non-Darcy flow, an easy and accurate calculation method for formation pressure analysis is presented. It can provide theoretical foundation for development design of water-bearing tight gas reservoirs. The analysis of calculation results demonstrates that the higher TPG is, the smaller formation pressure of water-bearing tight gas reservoirs spreads. In the same output, the reservoir sweep of non-Darcy gas flow is larger than that of non-Darcy liquid flow. And the pressure drop near wellbore is smaller than that of non-Darcy liquid flow, which is different from Darcy flow.

Abstract: Pressure bump is a serious disaster to threat coal mine production safety. The roof and floor strata in Kailuan coal mine are made of sandstone and mudstone with relatively poor rigidity. Most of mines have been into the deep mining stage over one thousand meters. High-stress becomes the key factor induced pressure bump. In this paper, according to coal mining strata, fault development, mine inflow and other geological factors, based on fracturing parameters of mine rock and wall rock in the pilot mines (Qianjiaying Mine, Tangshan Coal Mine), boundary conditions of the occurrence of pressure bump is tested by numerical simulation using RFPA software. It discusses the mechanism and laws of pressure bump under high stress in the deep mining. Mining face and roadway are taken real-time monitoring, using micro seismic monitoring system (MMS). The location and level of micro seismic events within the coal formation caused by breakdown could achieve precise position. Spatial distribution and characteristics of coal and rock bursting could be identified. The stability of coal and rock could be monitored real-time and analyzed. Pressure bump could be predicted and prevented effectively.

Abstract: Pressure bump in coal mine production safety is a serious disaster. Geological conditions in Kailuan Mine are complex. Coal strata based on the Carboniferous - Permian coal. The roof and floor are made of sandstone and mudstone with poor rigidity. Fault development and mine have large amount of water inflow. Most of mine are already getting into the mining stage over one thousand meters deep. Increasing stress and high stress induced pressure bump as a key factor. In this paper, according to geological characteristics of Kailuan Coal, it analyzes the impact and the laws of pressure bump in the representation of deep mining phase, which have certain reference for coal mine safety production.