大型环抛机抛光盘初始型面质量检测技术研究

为提高大型环抛机的抛光质量和效率,提出在产品抛光前,采用工业摄影测量技术对抛光盘初始型面质量进行检测。通过仿真校正板与抛光盘各部位的压强分布,分析了校正板与抛光盘之间的作用机理。结合抛光盘初始型面的分布趋势,发现校正板虽然能在很大程度上修正抛光盘的面型,促进被抛光产品的型面快速收敛,但是如果抛光盘存在“天然缺陷”,校正板的修正作用就达不到预期效果,进而导致产品抛光周期长、产品面型不理想等问题。

基于UG编程叶轮加工提高型面质量方法探究

文章针对目前使用UG8.5软件中的mill_multi_blade模块进行整体式叶轮的编程加工存在的影响型面质量的问题,及不合理的编程方法,提出改善方法与工件装夹、质检的注意事项,借助软件进行仿真加工较好地保证了叶轮表面质量又提高生产效率,促进利用软件指导产品的生产过程。

Estimation of surface tension of organic compounds using quantitative structure-property relationship

A novel quantitative structure-property relationship （QSPR） model for estimating the solution surface tension of 92 organic compounds at 20℃ was developed based on newly introduced atom-type topological indices. The data set contained non-polar and polar liquids, and saturated and unsaturated compounds. The regression analysis shows that excellent result is obtained with multiple linear regression. The predictive power of the proposed model was discussed using the leave-one-out （LOO） cross-validated （CV） method. The correlation coefficient （R） and the leave-one-out cross-validation correlation coefficient （Rcv） of multiple linear regression model are 0.991 4 and 0.991 3, respectively. The new model gives the average absolute relative deviation of 1.81% for 92 substances. The result demonstrates that novel topological indices based on the equilibrium electro-negativity of atom and the relative bond length are useful model parameters for QSPR analysis of compounds.

Experimental investigation on solar-flue gas chimney

Flue gases exhausted from thermal power plants contain more than 50% of the fuel thermal energy. In the present work, experimental investigation was carried out to study the utilization of thermal energy in flue gases to enhance the performance of modified solar chimney consisting of Savonius wind rotor. A modified solar chimney model was designed and fabricated to carry out experimental measurement. The model consists of thermal energy conversion unit; Savonius wind rotor and a chimney. The thermal energy in the flue gas transfers to the air particles in the air channel across the absorber plate and results in upward air stream due to the buoyancy effect. With an 9 absorber area of 2.36 re＇and flue gas mass flow rate of0.18 kg/s, air velocity＇ of 4.1 m/s was achieved at the top of the thermal unit. Increasing the mass flow rate of the flue gas to 0.24 kg/s enhances the air velocity to be 4.6 m/s. The results have demonstrated the possibility＇ of utilizing the thermal energy in the waste flue gas to enhance the performance of a solar chimney and facilitate the continuous operation during the absence of the sun.

A mass-conservative average flow model based on finite element method for complex textured surfaces

A mass-conservative average flow model based on the finite element method(FEM) is introduced to predict the performances of textured surfaces applied in mechanical seals or thrust bearings.In this model,the Jakobsson-Floberg-Olsson(JFO) boundary conditions are applied to the average flow model for ensuring the mass-conservative law.Moreover,the non-uniform triangular grid is utilized,which can deal with the problem of complex geometric shapes.By adopting the modeling techniques,the model proposed here is capable of dealing with complex textured surfaces.The algorithm is proved correct by the numerical experiment.In addition,the model is employed to gain further insight into the influences of the dimples with different shapes and orientations on smooth and rough surfaces on the load-carrying capacity.

Trend of mass change in the Antarctic ice sheet recovered from the GRACE temporal gravity field

It is important to quantify mass variations in the Antarctic ice sheet hybrid filtering scheme employing a combination of the decorrelated to study the global sea-level rise and climate change. A filter P3M6 and 300 km Fan filter was used, and the sur- face mass variations over the Antarctic are recovered from GRACE CSR RL04 monthly gravity field models from August 2002 to June 2010. After deduction of leakage errors using the GLDAS hydrological model and postglacial rebound effects using the glacial isostatic adjustment model IJ05, the variations in the ice sheet mass are obtained. The results reveal that the rate of melting of the Antarctic ice sheet is 80.0 Gt/a and increasing and contributes 0.22 mm/a to the global sea-level rise; the mass loss rate is 78.3 Gt/a in the West Antarctic and 1.6 Gt/a in the East Antarctic. The average mass loss rate increases from 39.3 Gt/a for the period 2002-2005 to 104.2 Gt/a for the period 2006-2010, and its corresponding contribution to the global sea-level rise increases from 0.11 to 0.29 mm/a, which indicates accelerated ice mass loss over the Antarctic since 2006. Moreover, the mass accumulation rates for Enderby Land and Wilkes Land along the coast of East Antarctica decrease for the period 2006-2008 but increase evidently after 2009.

RESEARCH ON STABILITY OF LIQUID FILM ON HOT SOLID SURFACE IMPINGED BY SMALL DROPLETS

A heat and mass transfer model was proposed for the thin liquid film on the hot solid surface cooled by the impinging small droplets, with consideration of the effect of the droplet impact, surface tension, thermocapillary, evaporation/condensation, and van der Waals attraction. The nondimensional equation for predicting the evolution of the interface of the thin liquid film was derived in the presented model with the relevant boundary conditions. The stability of the thin liquid film impacted by cool small droplets is discussed.