Purpose This paper aims to research the lubrication performance of large-size rectangular oil pad in hydrostatic thrust bearing for heavy computer numerical control (CNC) vertical lathe. Design/methodology/approach The research establishes the mathematical models of velocity, flux and pressure fields, etc., for lubrication performance distribution, and analyzes its load-bearing behavior. Findings When hydrostatic thrust bearing’s rotating speed is within ω1-ω2, the oil flow generated by plate’s relative motion is greater than that generated by pressure difference and centrifugal force, and in the opposite direction, making it not easy to emit friction heat, so the rotating speed range ω1-ω2 should be avoided for bearing. Originality/value The research provides powerful theoretical basis for the structure design, operating reliability and practical application of large size rectangular oil pad hydrostatic thrust bearing, and realizing the prediction of its lubrication performance.

Purpose The purpose of this study with the rapid development of the heavy/large mechanical equipment, the heavy computer numerical control (CNC) vertical lathe has become the ideal processing equipment for the parts of those mechanical equipments. The main factor which affects the machining quality and efficiency of heavy CNC vertical lathe is the mechanical properties of the hydrostatic thrust bearing. Design/methodology/approach This paper did the research based on the large size sector oil pad’s lubrication performance of the hydrostatic thrust bearing in the heavy/large equipments, establishing the lubrication performance distribution mathematical model of the velocity field, flow field, pressure field and so on, analyzing the bearing behavior of the large size sector oil pad. Findings The results show that the oil flow generated by the plate relative motion will be greater than that generated by the pressure difference in area B, with the rotational speed’s increasing of the hydrostatic thrust bearing, and the direction is opposite. The oil flow generated by the centrifugal force will be greater than that generated by the pressure difference in area C, with the rotational speed’s increasing of the hydrostatic thrust bearing, and the direction is opposite. When the rotational speed of the hydrostatic thrust bearing is too high, the friction heat will be not easy to be sent out. The bearing rotating speed should be lower than the comparatively smaller one of ω1 and ω2, which can help avoid the rise of too high temperature. Originality/value The research provides powerful theoretical foundation for practical application of the large size sector oil pad hydrostatic thrust bearing, its structure design and operating reliability, realizing the lubrication performance prediction of the large size hydrostatic thrust bearing.

in chips and dramatically reducing reliability and performances [1][2][3]. So thermal control has become a hot issue for the high-power electronic components with high heatflux, which urgently needs solving. Miniature/micro heat pipes have become ideal radiating devices for high heatflux chips because of their high heat conductivity and no need for extra electronic driving. As a heat pipe's heat transfer performance is mainly determined by its wick structure, and the compound structure of sintered wick on a grooved substrate can have both sintered pipes' greater capillary force and grooved pipes' lower back-flow resistance to working fluid, therefore can better suit the trend of being light, thin, short and miniature for high heat-flux electronic devices [4][5][6]. But the key problems are how to fabricate ideal micro grooves in the inner wall of thin circular copper pipes to reduce the back-flow resistance to working fluid, and how to sinter a thin layer of copper powders on these micro grooves to boost capillary force, and consequently MHPs' heat transfer performances.The higher requirement for thermal control in so many industries has attracted more scholars to research on MHPs. In recent years, Suman [7] modelled surface tension gradient for grooved MHPs, analyzed the impacts of surface tension gradient on heat pipes' performances from the perspectives of working fluid's curvature radius, pressure and velocity, and concluded that heat transfer performances can be greatly enhanced by affixing appropriate surfactant or surface charge, which can decrease surface tension gradient of working fluid in heat pipes. Oh et al. [8] proposed a technique of laser-induced thermochemical etching, which can help fabricate triangle grooves with smooth surface in copper pipes' inner wall. Xin et al.[9] fabricated loop heat pipe (LHP) wicks through cold pressing and loose powder sintering respectively, tested the porosity, permeability and pore radius of two types of wicks, and discovered that the Abstract Micro heat pipes (MHPs) with excellent heat transfer performance have been the ideal radiating components to meet increasingly higher requirements posed by high heat-flux products. Based on MHPs' working principle, this study deduced capillary limit of a novel MHP with compound structure of sintered wick on grooved substrate, and probed into its forming mechanism: first, highspeed oil-filled spinning was applied to fabricating micro grooves, with optimal spinning and drawing speeds determined; then a mini-type vibration machine was used to help fill copper powders fast and uniformly, with appropriate sintering temperature and time fixed; the manufacturing method that integrates vacuum-pumping-cold-welding with secondary-degassing-cold-welding to increase vacuumizing efficiency. The results of experiments on its heat transfer performance show that the MHPs with sinteredwick-on-grooved-substrate structure fabricated through the proposed forming method can not only acquire much better heat transfer performance, but have advantag...

Stirred tank reactor is one of the three typical chemical machinery equipments and widely used in petroleum, chemical, pharmaceutical and other industrial fields .It is the basis of understanding the flow of fluid in stirred tank for optimizing design of reactor. This paper aims at the process of suspension polymerization of polyvinyl chloride (PVC) which is an important raw material of chemical production, and uses conventional design method to design the PVC stirred tank of 50m3 from the structure design. According to the fluid dynamics theory, standard K-E turbulent calculation model is established under the function of impeller, the corresponding boundary conditions are listed, and the grid is carried out successfully. And finally the FLOTRAN CFD software is used to simulate the complex flow field and flow pattern according to the multiple reference frame method.

The peak of power consumption will be brought by the rapid development of the industry. Thermal power is still the main component of electric energy at present. More and more attention has been paid on the atmospheric pollution caused by the thermal power plant in our country. The sulfur dioxide (SO2), one of the thermal power plant flue gases, is dangerous to the environment and human. Effective SO2 control technology can not only reduce the environmental pollution but also the sulfur can be recovered in order to conserve resources.