Experimental Research on Gas-Liquid Two-Phase Spiral Flow in Horizontal Pipe

In view of the importance of gas-liquid two-phase spiral flow and the few research reports at home and abroad,the gas-liquid two-phase spiral flow patterns have been researched in a horizontal pipe with different parameters investigated by means of observation and a high-speed camera.Since the appearance of spiral flow makes the distribution of twophase flow more complicated,the flow patterns appearing in the experiments were divided into the Spiral Wavy Stratified Flow(SWS),the Spiral Bubble Flow(SB),the Spiral Slug Flow(SS),the Spiral Linear Flow(SL),the Spiral Axial Flow(SA),and the Spiral Dispersed Flow(SD) by the observations and with reference to the predecessors’ research achievements.A flow pattern map has been drawn up.The influence of velocity,vane angle and vane area on flow pattern conversion boundary and pressure drop has been studied,with a solid foundation laid for the future research work.     

Purification Processes and Market Potential of Bromelain in Brazil

Bromelain is the denomination given to the group of endoproteases obtained from members of Bromeliacea family. These enzymes have a wide range of proven applications and have been an object of study for worldwide researchers for decades. Over the years, several different downstream processes were studied in order to determine which technique would be worthwhile to be implemented in Brazil and provide the national market with such product. The objective of the present study is to relate the main studies in Brazil that has proven that bromelain purification can be cost-effective, in addition to the well-known benefits owned by such enzymes, and highlight the applications that create their market potential in the Brazilian market.     

α-β坐标系下瞬时无功功率的笼型异步电机转子故障诊断

根据α-β两相静止坐标下的瞬时无功功率理论,推导出笼型异步电动机定子瞬时无功功率在正常状态、转子断条故障、转子偏心故障、以及两者的复合故障状态下的表达式,并提取出不易被基频淹没、易于辨识的故障特征频率,以此达到诊断电机的目的。同时,转子复合状态下的故障特征频率得到有效分离。最后,利用双Hilbert变换,滤除瞬时无功功率频谱中的直流成分,更好地突出故障特征分量。实验采集定子三相电压电流,经过坐标变换,运用两相静止坐标系瞬时无功功率理论得到瞬时无功功率,进行频谱分析,验证了此法对电机转子各种故障诊断的准确性。     

井下混合流体光谱在线分析技术研究

地层流体光谱实时分析技术通过光谱学原理对地层流体进行在线测量,可为地层流体取样提供重要参考依据。针对取样过程中出现的水基泥浆对地层原油污染的情况,提出一种基于近红外光谱分析技术的油水比在线测量方法。通过对3组不同的光谱预处理方式的建模效果进行分析和对比,证明了采用校正后连续光谱进行偏最小二乘法回归建模能够更准确地预测混合流体流经光学窗口时的含油比率。     

丙烯酰胺在聚乙二醇水溶液中可逆加成-断裂链转移聚合

结合双水相聚合和可逆加成-断裂链转移(RAFT)聚合,提出在聚乙二醇(PEG)水溶液中进行丙烯酰胺(AM)的RAFT双水相聚合,考察反应条件对聚合反应速率和产物分子量及分布的影响。结果表明:高引发剂浓度、单体浓度和聚合温度可以提高初始聚合速率和最终转化率,PEG和RAFT试剂浓度的增加会导致聚合速率减慢和最终转化率降低;峰值聚合速率随引发剂浓度、单体浓度和聚合温度的增加而增大,同时峰值聚合速率对应的时间提前;RAFT试剂浓度增加会推迟峰值聚合速率对应的时间,但可制得分子量分布较窄的产物;PEG浓度的增加会导致产物的分子量分布变宽。     

油水两相流润滑轧机油膜轴承的摩擦行为分析

目的研究含水润滑油对轧机油膜轴承的摩擦学性能的影响。方法选取轧机油膜轴承为研究对象,利用油水两相流体数学模型和弹流润滑方程研究轧机油膜轴承在等温条件下的润滑特性,分析油水两相流体润滑膜的压力、膜厚分别随含水率、滑滚比、轴颈间隙、主轴转速和轧制力的变化关系。结果水介入润滑油之后,随着含水率的增加,油水两相流体的黏度先增加,在含水率为30%左右时达到最大值(0.08 Pa·s),之后又迅速减小,直至接近于纯水的黏度(0.001 Pa·s)。当含水率为30%时,无量纲膜厚达到最大值(0.82),当含水率为90%时,无量纲膜厚达到最小值(0.68)。结论随着含水率的增加,油水两相流体由油包水流型转化为水包油流型,压力变化不大,膜厚先增加后减小,作为润滑剂,油包水流型比水包油流型具有更好的润滑性能,且在流型转变点处的润滑性能最优。随着滑滚比和轧机油膜轴承主轴转速的增加,压力减小,承载能力减弱,膜厚增加,润滑性能增强。随着轴颈间隙和外部轧制力的增加,压力增加,承载能力增强,膜厚减小,润滑性能减弱。     

超声滚压Ti-6Al-4V微观组织对应力应变行为的影响

目的 通过超声滚压提高Ti-6Al-4V的屈服强度。方法 将超声振幅作为唯一变量,设置0、5、7、10μm4组试验,分析Ti-6Al-4V被加工表面及表面以下30～50μm处的应力应变行为。通过X射线衍射仪（XRD）测试不同超声振幅下Ti-6Al-4V的两相分布。采用扫描电子显微镜（SEM）,分析不同超声振幅下Ti-6Al-4V表面层塑性变形程度。使用能谱仪（EDS）观察不同超声振幅下Ti-6Al-4V表面层元素组成分布。通过万能试验机获得不同超声振幅下Ti-6Al-4V的应力应变曲线。结果 Ti-6Al-4V表面层塑性变形程度随着超声振幅的增大而增大。Ti-6Al-4V被加工表面的β相体积分数随着超声振幅的增大呈先减小后增大的趋势。当超声振幅为7μm时,Ti-6Al-4V被加工表面β相的体积分数最大（19.70%）。超声滚压Ti-6Al-4V表面层中β相的体积分数沿深度递减。Ti-6Al-4V表面层α相稳定元素Al和β相稳定元素V未出现明显与两相体积分数相同的变化趋势。Ti-6Al-4V材料的屈服强度随着超声振幅的增大呈先减小后增大的趋势。当超声振幅从5μm增至10μm时,Ti-6A...     

火箭喷管两相流动性能计算公式

为方便应用两相流动模型对火箭发动机进行性能预示以及提高性能预示精度,利用火箭喷管内的一维两相流动的数值计算数据,通过对火箭喷管一维两相流动参数与纯气相流动变化规律的对比计算与分析,得到火箭喷管在两相流动下的性能(包括质量流量、排气速度和压强比)计算公式.该计算公式考虑了两相流动中所有的因素,如比热比、凝聚相尺寸、凝聚相百分比,甚至喷管尺寸等,具有广泛的适应性.利用这些公式与理论计算结果进行了对比,结果表明其理论预示精度达到千分位至万分位,并使得两相流动模型在火箭发动机中的应用分析得到简化,有利于提高火箭发动机性能的预示精度.     

Semianalytical method of two-phase liquid transport in shale reservoirs and its application in fracture characterization

This study presents a new semi-analytical method to simulate the two-phase liquid transport in hydraulic fractures (HF) and matrix system, which can be applied to characterize HF attributes and dynamics using the flowback data from hydraulically fractured shale oil wells. The proposed approach includes a fracture model for HF properties calculation and a matrix model capable of considering multiple liquid transport mechanisms in shale nanopores. The proposed method is first validated with the numerical simulation then applied to a field example in Eagle Ford shale. The numerical validation confirms that our method can accurately characterize fracture attributes and closure dynamics by closely estimating the initial fracture permeability, pore-volume, compressibility, and permeability modulus. Furthermore, the analysis results from numerical simulation and a field example both indicate a clear flow enhancement and deficit for oil and water transport, respectively, due to the slippage effect and variation of fluid properties inside nanopores.     

气固流化床介尺度结构形成机制及过滤曳力模型研究进展

气固流化床中,介于颗粒与宏观尺度间的复杂的时空多尺度结构（介尺度结构）将完全改变气固相间作用规律,加大了流态化系统调控及预测的难度。为此,需要构建考虑结构影响的相间本构关系。其中,曳力作为影响流态化动力学特征的主导因素,对其研究尤为重要。从结构产生演化的机制出发,概述结构影响曳力的机理,以模型构建流程的角度对结构和过滤两类模型进行总结,并重点综述过滤模型构建在提升准确性、有效性、通用性和考虑更多物理机制方面的最新进展。研究表明：提升模型通用性和考虑真实系统中更丰富的物理机制仍是建模中亟待解决的问题,结合结构演化机制理性建模和充分发挥机器学习数据分析处理优势或是曳力建模进一步发展的关键。