To address the problems of low efficiency, high cost and low automatic level existing in traditional laser tracking measurement systems, a triple-laser trackers measurement system for large-scale parts assembly is proposed. The system is composed of three laser trackers, and can fulfill automatic measurement throughout whole assembly process. Multiple extended datum marks are generated to increase assembly precision, whose 3D coordinates are calculated by known distances. Mathematical model is established, and simulation is accomplished. The simulation results show that the proposed system features relative high precision, automatic measurement and wide application.
Based on the practice of Huolang-yu tunnel of Mixing road reconstruction, this paper studies the monitoring of ground surface vibration and the technology of controlled blasting. The results show: (1) the ground surface vibration declines from constructed position to non-excavated areas along tunnel excavation direction. (2) The vibration control of wedge cutting holes blasting is the key to reduce or eliminate shallow tunnel vibrating calamity. And the replacement of the multi-stage small wedge cutting holes to the big wedge cutting holes ameliorates blasting vibration and rock fragmentation. (3) The overall monitoring of shallow tunnel blasting vibration and the effects, and optimum of the blasting design not only reduce blasting vibration but also ensure large circulation footage.
To address the problems of low efficiency, high cost and low automatic level existing in traditional laser tracking measurement systems, a laser tracking-vision guiding measurement system for large-scale parts assembly is introduced in this paper. The system is composed of mono-camera and a laser tracker, can fulfill real-time tracking and automatic measurement throughout the whole assembly process. A global calibration method based on public planes and a method for finding the 3D positions of the target reflectors based on monocular vision measuring are expounded. Mathematical model is established, measurement system is built, and the experiment is accomplished. The experiment result indicates that the proposed system features relative high degree of automation and high measuring speed, has future in practical application.
The usage rate of sucker rod centralizer more and more broad with the development of a sucker rod pump , adding sucker rod centralizer is very effective to reduce the impact of rod and tubing wear, increase the sucker rod and tubing service life, reduce the frequency of maintenance and the production cost .Starting from the actual borehole parameters, comprehensively considering bending stress condition of sucker rod string in the three-dimensional hole, analyzing of the axial load of sucker rod and lateral loads, and use the lateral deformation of the sucker rod equal annular space between tubing and sucker rod as the basic principle of centralizer allocation, to calculate and analysis of the spacing configuration of the stabilizer. The example analyzed shows that optimization design of sucker rod centralizer spacing has a certain reference value.
This paper aims to investigate fixed composition natural gases including N2, CH4 and C2H4 energy separation effect in vortex tube. Energy separation phenomena of those gases were investigated by means of three-dimensional Computational Fluid Dynamics (CFD) method. Flow fields of natural gases in fixed inlet boundary conditions were simulated. The results main factors were found that affect the energy separation with cold mass fraction being 0.7 and pressure drop ratio being 3.90. At the same time, this paper has illustrated the effects and tendencies of energy separation with gases in the tube under the same cold mass flow fraction and cold pressure ratio. The results show mixture gases total temperature difference effect is unchanged varied with the cold mass fraction; CH4% has no effect on the vortex cold end temperature separation, but varied of CH4% has an influence in total temperature and hot end separation effect; total temperature separation effect of CH4% was divided into two sections, one is0%-80%, and the other 80%-100%.
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