用于速冻火锅料的梳理和分离装置

本文针对火锅料生产中速冻隧道的人料和出料环节存在堆积和结块问题,设计了入料梳理装置和冲击分离装置,将送人速冻隧道的堆积物料梳理成有序排列的物料,将速冻后粘结物料冲散。介绍了梳理装置和冲击分离机的结构设计、工作原理和用途。     

一种多用真空吸具的设计

本文介绍了普通真空吸具的结构组成,针对使用同一个吸具吸取不同曲率半径外球面工件的设计需求,分析了实现途径,设计了一种采用球头密封结构的可摆动型真空吸盘.在此基础上,对普通真空吸具进行了改进设计,介绍了多用真空吸具的结构组成、工作原理,并介绍了真空吸取力的计算方法,以及关键参数的选用建议.     

真空吸料在远程送料的应用

粒料塑料原料在远程输送可以采用正压压送，或者负压真空吸料。对于大批量单一原料一般可采用正压压送比较合适，而对于小批量和经常变换原料品种规格的则运用真空吸料就再好不过。下面谈谈如何运用真空吸料进行远程送料。     

水环真空泵在真空吸送中的应用

介绍了真空吸送中水环真空泵的选择方法以及在使用中应当注意的一些问题。     

不规则宽粒径石灰石粉脱硫及气力输送技术

通过分析干法脱硫技术及其影响因素,如石灰石性能和石灰石颗粒直径等,提出脱硫剂的选择及气力输送的方式,同时分析了气力输送中的问题,如透气性差和保气性差引起的不易流化等,并相应提出解决办法和输送设计方案。针对不规则宽粒径石灰石粉粒具有的特殊颗粒学特性和复杂气固两相流场,提出了解决方案,为更好地设计石灰石粉气力输送系统提供参考。     

斜管内流化催化裂化催化剂颗粒流的流态识别

在内径为150 mm、长度为3 400 mm、倾角为45°的斜管实验装置上,以流化催化裂化催化剂为固体颗粒物料,采用动态压力传感器测量斜管内颗粒流下行过程中的压力变化,研究斜管中颗粒流的流态变化。结果表明:随着下行颗粒流量的增大,颗粒流的流态依次为Ⅰ型分层蠕动流动、II型分层蠕动流动、过渡分层流动、分层流动和流化流动;斜管中下行颗粒流的流态可以用动态压力进行识别。     

高真空吸送装置的设计和实践

介绍了高真空吸送装置的原理和结构，对华能大连电厂煤仓间的高真空吸收系统作了分析计算，并作了改进设计．高真空吸进装置应用在华能南通电厂，取得了良好效益。最大真空度可以从以往的-50kPa提高到-93．3kPa．从而证实了-50kPa-－95kPa的高真空范围是个值得开发、利用的新领域。     

旋风式除尘器内部气固两相流流动数值模拟

本文利用流体力学计算软件star-cd对旋风式除尘器内部气固两相流进行了三维数值模拟,通过对计算结果的分析,讨论了气固两相流的速度分布,压力分布规律,以及固体颗粒的运动轨迹,进一步阐述了旋风除尘器的工作原理.     

纸浆模塑真空吸滤成形机理研究

在纸浆模塑制品的自动生产过程中，真空吸滤成形是十分关键的工序。如何控制和提高吸滤成形的效率，并对吸滤成形工艺进行较精确的控制，会直接影响到产品的几何尺寸、表面光滑度、机械强度等主要产品质且指标。本文对纸浆相丹的真空吸滤成形过程进行了理论分桥，建立了相对应的真空吸滤模型，探讨了影响真空吸滤效率的因素，提出了型坯空隙率修正系数，并根据模型通过计算和推导，得出对于某一特定的浆料的真空吸滤过程中纸坯厚度、过滤时间及压力差之间的关系式。应用该式得到的计算结果与实测值基本相符。同时对主要工艺条件之间的规律进行了定量定性分桥，分桥结论对降低能耗，提高生产率具有实用价值。     

一种基于旋流分离原理光释光测年样品制备方法

光释光测年（OSL）样品制备的目标是提取土壤中一定粒径范围内的石英和长石颗粒（中颗粒38～63μm）。针对当前样品提取过程中效率低、耗时长等诸多问题,提出一种光释光测年样品制备新方法。该方法基于水力旋流分离原理,采用3D打印技术研制微型水力旋流器（浓缩器）,设计2种改进型带筛网的微型水力旋流器（粗选器和精选器）,根据旋流分离器分离特性选择适宜的参数;研制样品前处理装置,该装置包括四个模块（粗选模块、反应池模块、精选模块和控制模块）;通过该装置能快速分离提取5种理化性质各异的土壤颗粒,利用激光粒度仪测试分离效果,结果表明,分离提取的颗粒集中分布在35～65μm范围内,分离效率分别为77.8%、90.4%、77.2%、80.3%、80.9%,粒径均值为40～50μm。该方法提取的土壤长石、石英颗粒满足光释光测年样品制备的要求。     

Some aspects of the stability of vertical pneumotransport of solid particles

The upper boundary of the critical transition region separating stable (normal) pneumotransport from a through two-phase flow with internal circulation of the particles is determined on the basis of an analysis of pressure losses in a two-phase flow in a vertical channel. Simple dimensionless relations for calculation of the velocities U_cl and U_opt determining the lower and upper boundaries of the transition region are obtained.     

真空管道垃圾收集系统关键工艺参数优化设计

基于水平真空管道内空气一固体垃圾气固两相流压力损失计算关系式，并根据计算结果，探讨压力损失、气流速度及垃圾与空气量输送比这三个关键工艺参数的关系；最后提出一种计算经济风速及经济气固输送比的方法。本研究成果对真空管道垃圾收集工艺及装置选用及设计有指导意义。     

利用卷式膜分离器分离有机蒸气／氮气混合气的过程研究

利用硅橡胶（ Ｌ Ｔ Ｖ）／ 聚醚酰亚胺（ Ｐ Ｅ Ｉ） 复合膜做成的卷式膜分离器,进行了有机蒸气（ Ｖ Ｏ Ｃ）／ 氮气混合气分离过程的研究,主要考察了原料气的处理量、浓度、压力以及渗透侧真空度对有机蒸气脱除率的影响．实验结果表明,当压力为０ ．６ Ｍ Ｐａ ,处理量为１ ．０３ ｍ ３／ｈ ,渗透侧真空度为０ ．０２ Ｍ Ｐａ 时,有机蒸气的脱除率达到９０ ％ 以上;提高原料气侧的压力以及在渗透侧抽真空,都可以使脱除率增加     

Soil vapor extraction of chlorinated solvents at an industrial site in Brazil

This study presents the design, monitoring and remediation strategy for a soil vapor extraction (SVE) system installed at an industrial site contaminated with a mixture of organic compounds, in particular 1,2 dichloroethane, carbon tetrachloride and chloroform. The unsaturated zone at the site is very deep and presents near ideal conditions for SVE, with the contaminated portion of the porous media characterized by alluvial deposits of a well graded sand followed by a capillary barrier at 28 m of depth, which limited DNAPL downward migration. The soil cleanup time and the optimal removal rates of mass, considering different values of vacuum/discharge applied in the SVE system, have been estimated through the use of numerical sensitivity analysis. Results of the pilot-scale testing activities allowed for the calibration of flow and contaminated mass transport models and the determination, in a preliminary phase, of the infiltrated mass of different compounds.     

基于分子流传感元件的真空腔体漏率测量方法

本文介绍了一种基于分子流传感元件的真空腔体漏率测量方法,该方法通过分子流传感元件测量真空腔体整体漏率,采用的测量装置由气体流量测量系统、真空抽气系统、恒温系统等部分组成.在测量系统中,流经传感元件的气流处于分子流状态,通过测量传感元件两端的差压,计算质量流量,可以得到真空腔体的整体漏率.实验中对多个真空腔体漏率的测量结...     

State-of-the-art of two-phase flow and flow boiling heat transfer and pressure drop of CO2 in macro- and micro-channels

A comprehensive review of flow boiling heat transfer and two-phase flow of CO₂ is presented that covers both macro-channel tests (diameters greater than about 3 mm) and micro-channel investigations (diameters less than about 3 mm). The review addresses flow boiling heat transfer experimental studies, macro- and micro-scale heat transfer prediction methods for CO₂ and comparisons of these methods to the experimental database, highlighting the various limitations of current approaches and the divergence of some data sets from others. In addition, two-phase flow pattern results available in the literature are summarized and compared to some of the leading flow pattern maps, showing significant deviations for CO₂ from the maps prepared for other fluids at lower pressures. Available two-phase pressure drop data for CO₂ are also compared to leading prediction methods.     

真空预冷中捕水器与真空泵的优化匹配研究

真空预冷过程中捕水器能力与真空泵抽气能力匹配决定着预冷过程的质量。通过对预冷过程中水蒸汽为理想气体的假定，分别计算了捕水器和真空泵在匹配时所需要的能耗。在这基础上，对真空预冷系统所需要的能耗进行了计算，并在一台真空预冷实验台上对装载率为60％时的白菜了实验研究，并和理论结果进行了比较。结果表明，在确定的工作条件下，单位时间内的能耗只是与抽气量有关，而整体能耗则取决于所需要预冷的果蔬，与系统参数无关。     

Experimental analysis of preferential flow in dry snowpack

Preferential flow in snowpack is an important phenomenon and influences snowpack modeling, avalanche forecasting and runoff forecasting for snow-covered basins. However, the theoretical foundation is not sufficient to develop a snowpack model that includes a water movement process including preferential flow. The water ponding process, which is caused by the water-entry value of capillary pressure, is a key process for capillary pressure overshoot, water saturation overshoot and the formation of preferential flow in other porous media like homogeneous dry sand. We attempted to apply theories of preferential flow in homogeneous dry soil to initially dry snow. Infiltration experiments into homogeneous dry snow and theoretical analysis were carried out to reveal the developing process of preferential flow during infiltration into a homogeneous dry snowpack and to obtain critical conditions for that process. The capillary pressure was measured just above the interface between the dry/wet snow layer by the tensiometer. Concurrently we conducted experiments with a dye-tracer in order to observe the flow patterns. The capillary pressure overshoot and the water-entry value were observed in experiments for samples of a large grain diameter (> 0.25 mm). The capillary pressure overshoot was directly linked to the formation of preferential flow. The velocity criterion and the pressure head criterion which are used to predict preferential flow for dry sand were able to predict the preferential flow for three out of our four different samples. The velocity criterion failed, however, to predict the stable case (no occurrence of preferential flow) for the experiment with the smallest grain diameter and pore size. Good agreement experimental results and both criterions were obtained from the analysis. These results showed some similarities between the developing process of preferential flow in dry sand and in dry snowpack.     

Influence of gravity state upon bubble flow in the deep penetration molten pool of vacuum electron beam welding

The governing equations of two-dimensional bubble flow model for gas–liquid two-phase system in deep penetration molten pool of vacuum electron beam welding were developed according to the laws of mass and momentum conservation. The separation models of gas and liquid convections in bubble flow were formed by regarding the gas phase in molten pool as a particle phase, and the vacuolar fraction, velocity slip, pressure gradient and other factors were introduced into the models. The influences of the gravity state upon the convection of bubble flow and the distribution of cavity-type defects in molten pool of AZ91D magnesium alloy were studied by the method of numerical simulation based on the mathematical models. The results showed that the gravity is an important factor to drive the convection of the bubble flow in the deep penetration molten pool during vacuum electron beam welding. The gravity has an impact on the gas distribution in molten pool, thus affects the distribution of cavity-type defects in weld. Because of the gravity contributing to driving the convection of bubble flow, it is conducive to the escape of gas phase in molten pool and reducing the air rate. A larger convection velocity of gas phase is helpful to the escape of gas phase, thus reduce the tendency of cavity-type defects.     

Numerical study of the two-phase flow characteristics of slush nitrogen

The fundamental two-phase flow characteristics of slush nitrogen in a pipe are numerically investigated to develop effective cooling performance for long-distance superconducting cable. First, the governing equations of two-phase slush nitrogen flow based on the unsteady thermal non-equilibrium two-fluid model are constructed and several flow characteristics are numerically calculated taking into account the effects of the slush volume fraction, the thermodynamic behavior of slush, and the duct shape. Furthermore, the numerical results are compared with previous experimental results on pressure loss measurement and visualization measurement in two-phase slush nitrogen flow along the longitudinal direction of the pipe. Results of this research show that it is possible to reduce the pressure loss by using a two-phase slush flow under the high Reynolds number condition and by applying the appropriate volume fraction of slush particles. The optimized thermal flow conditions for cryogenic two-phase slush nitrogen with practical use of latent heat for slush melting are predicted for the development of a new type of superconducting cooling system.