A Pressure-Drop Model for Oil-Gas Two-Phase Flow in Horizontal Pipes

The accurate prediction of the pressure distribution of highly viscous fluids in wellbores and pipelines is of great significance for heavy oil production and transportation.The flow behavior of high-viscosity fluids is quite different with respect to that of low-viscosity fluids.Currently,the performances of existing pressure-drop models seem to be relatively limited when they are applied to high-viscosity fluids.In this study,a gas-liquid two-phase flow experiment has been carried out using a 60 mm ID horizontal pipe with air and white oil.The experimental results indicate that viscosity exerts a significant influence on the liquid holdup and pressure drop.At the same gas and liquid volume,both the liquid holdup and pressure drop increase with an increase in the viscosity.Combining two existing models,a modified pressure drop method is developed,which is applicable to horizontal pipes for different viscosities and does not depend on the flow pattern.This new method displays a high accuracy in predicting the new experimental data presented here and other published data in literature.

An improved effective liquid drop model for cluster radioactivity

The effective liquid drop model(ELDM)is improved by introducing an accurate nuclear charge radius formula and an analytic expression for assaulting frequency.Within the improved effective liquid drop model(IMELDM),the experimental cluster radioactivity half-lives of the trans-lead region are calculated.It is shown that the accuracy of the IMELDM is improved compared with that of the ELDM.At last,the cluster radioactivity half-lives that are experimentally unavailable for the trans-lead nuclei are predicted by the IMELDM.These predictions may be useful for searching for new candidates for cluster radioactivity in future experiments.

Systematic study of cluster radioactivity within the generalized liquid drop model

Cluster radioactivity is studied within the generalized liquid drop model(GLDM),in which the shell correction energy,pairing energy,and cluster preformation factor are considered.The calculations show significant improvements and can reproduce the experimental data within a factor of 8.04 after considering these physical effects.In addition,the systematic trend of the cluster preformation factors is discussed in terms of the N_(p)N_(n)scheme to study the influence of the valence proton-neutron interaction and shell effect on cluster radioactivity.It is found that log10Pcis linearly related to N_(p)N_(n).This is in agreement with a recent study[L.Qi et al.,Phys.Rev.C 108,014325(2023)],in which log10Pc,obtained using different theoretical models and treatment methods than those used in this study,also had a linear relationship with N_(p)N_(n).Combined with the work by Qi et al.,this study suggests that the linear relationship between log10Pcand N_(p)N_(n)is model-independent and both the shell effect and valence proton-neutron interaction play essential roles in cluster radioactivity.An analytical formula is proposed to calculate the cluster preformation factor based on the N_(p)N_(n)scheme.In addition,the cluster preformation factors and the cluster radioactivity half-lives of some heavy nuclei are predicted,which can provide a reference for future experiments.

Systematic study ofαdecay half-lives within the Generalized Liquid Drop Model with various versions of proximity energies

It is universally acknowledged that the Generalized Liquid Drop Model(GLDM)has two advantages over otherαdecay theoretical models:introduction of the quasimolecular shape mechanism and proximity energy.In the past few decades,the original proximity energy has been improved by numerous works.In the present work,the different improvements of proximity energy are examined when they are applied to the GLDM for enhancing the calculation accuracy and prediction ability ofαdecay half-lives for known and unsynthesized superheavy nuclei.The calculations ofαhalf-lives have systematic improvements in reproducing experimental data after choosing a more suitable proximity energy for application to the GLDM.Encouraged by this,theαdecay half-lives of even-even superheavy nuclei with Z=112-122 are predicted by the GLDM with a more suitable proximity energy.The predictions are consistent with calculations by the improved Royer formula and the universal decay law.In addition,the features of the predictedαdecay half-lives imply that the next double magic nucleus after ^(208)Pb is ^(298)Fl.

Investigation of proton radioactivity with the effective liquid drop model

Proton radioactivity has been investigated using the effective liquid drop model with varying mass asymmetry shapes and effective inertial coefficients. An effective nuclear radius constant formula replaces the old empirical one in the calculations. The theoretical half-lives are in good agreement with the available experimental data. All the deviations between the calculated logarithmic half-lives and the experimental values are less than 0.8. The root-mean-square （rms） deviation is 0.523. Predictions for the half-lives of proton radioactivity are made for elements across the periodic table. From the theoretical results, there are 11 candidate nuclei for proton radioactivity in the region Z〈51. In the region Z〉83, no nuclei are suggested as probable candidate nuclei for proton radioactivity within the selected range of half-lives studied.

Alpha decay half-lives of heavy nuclei within a generalized liquid drop model

Theoretical α-decay half-lives of the heaviest nuclei are calculated using the experimental Qα value. The barriers in the quasi-molecular shape path is determined within a Generalized Liquid Drop Model (GLDM) and the WKB approximation is used. The results are compared with calculations using the DensityDependent M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulae. The calculations provide consistent estimates for the half-lives of the α decay chains of these superheavy elements. The experimental data stand between the GLDM calculations and VSS ones in the most time.

Spontaneous Fission Barriers Based on a Generalized Liquid Drop Model

The barrier against the spontaneous fission has been determined within the Generalized Liquid Drop Model （GLDM） including the mass and charge asymmetry, and the proximity energy. The shell correction of the spherical parent nucleus is calculated by using the Strutinsky method, and the empirical shape-dependent shell correction is 6mp10yed during the deformation process. A quasi-molecular shape sequence has been defined to describe the whole process from one-body shape to two-body shape system, and a two-touching-ellipsoid is adopted when the superdeformed one-body system reaches the rupture point. On these bases the spontaneous fission barriers are systematically studied for nuclei from 2a^Th to 249 Cm for different possible exiting channels with the different mass and charge asymmetries. The double, and triple bumps are found in the fission potential energy in this region, which roughly agree with the experimental results. It is found that at around Sn-like fragment the outer fission barriers are lower, while the partner of the Sn-like fragment is in the range near l^SRu where the ground-state mass is lowered by allowing axially symmetric shapes. The preferable fission channels are distinctly pronounced, which should be corresponding to the fragment mass distributions.

Systematic study of theαdecay preformation factors of the nuclei around the Z=82,N=126 shell closures within the generalized liquid drop model

In this study,we systematically investigate theαdecay preformation factors,Pα,and theαdecay half-lives of 152 nuclei around Z=82,N=126 closed shells based on the generalized liquid drop model(GLDM)with Pαbeing extracted from the ratio of the calculatedαdecay half-life to the experimental one.The results show that there is a remarkable linear relationship between Pαand the product of valance protons(holes)Np and valance neutrons(holes)Nn.At the same time,we extract theαdecay preformation factor values of the even–even nuclei around the Z=82,N=126 closed shells from the study of Sun et al.[J.Phys.G:Nucl.Part.Phys.,45:075106(2018)],in which theαdecay was calculated by two different microscopic formulas.We find that theαdecay preformation factors are also related to NpNn.Combining with our previous studies[Sun et al.,Phys.Rev.C,94:024338(2016);Deng et al.,ibid.96:024318(2017);Deng et al.,ibid.97:044322(2018)]and that of Seif et al.,[Phys.Rev.C,84:064608(2011)],we suspect that this phenomenon of linear relationship for the nuclei around the above closed shells is model-independent.This may be caused by the effect of the valence protons(holes)and valence neutrons(holes)around the shell closures.Finally,using the formula obtained by fitting theαdecay preformation factor data calculated by the GLDM,we calculate theαdecay half-lives of these nuclei.The calculated results agree with the experimental data well.

Investigation on Pressure Drop of Fluid-Solid Mixture Flow through Pipes Using CFD and SK Model

The carrier fluid (air or water) is used to transport solid material from the source place to its destination point through pipeline. Using air as carrier fluid to transport solid material through pipeline is called Pneumo transport, whereas transporting material with water or any other liquid through pipeline is called as hydraulic transport. A large number of installations are now available globally to transport solid materials to short, medium, and long distances using water/air as carrier fluid. However, the design of such system of pipeline is still an empirical art. In the present investigation, one generalized mathematical model developed by Shrivastava and Kar (SK Model) and CFD models were used and compared with experimental results for pneumatic and hydraulic transport of granular solids. The motivation of present work is to find the accuracy of SK model based on analytical, empirical and semi-empirical for the prediction of pressure drop and comparing the result with CFD based on mathematical equation for the mixture flow in the horizontal and vertical pipe lines. The comparison of pressure drop results obtained by using SK model and CFD model were validated with the experimental results for pneumatic and hydraulic transport of solids through. From the comparison results, it was observed that the results of pressure drop predicted by SK model are more accurate than the CFD models for all the cases considered.

自由落体作用下不同刚度楔形体板架结构响应特性的仿真及试验研究

目的分析艏部板架结构在砰击载荷作用下的极限承载能力。方法将艏部简化成二维楔形体板架形式,并基于ALE流固耦合对具有2种不同加筋刚度的楔形体板架的砰击响应开展数值仿真分析,预报不同位置的砰击压力和结构塑性变形的变化规律。为验证数值仿真结果的准确性,分别对角钢和T形材这2种加筋板结构开展自由落体砰击试验。结果数值仿真结果与试验测量结果吻合较好。其中,试验与仿真的塑性应变最大误差的测点发生在加强筋的面板和腹板,分别为17.06%以内和17.50%。此外,在相同砰击载荷的情况下,2个模型的应变量值都在相同的数量级中。结论无论是试验结果还是仿真结果,带T形材加筋板的结构响应更大,这说明砰击载荷作用下T形材抵抗变形的能力要比角钢更强。

晶上系统电源分配网络建模及IR-drop研究

为预测和评估晶上系统电性能,提出了一种结合电磁和分析模拟的晶上系统电源分配网络(PDN)建模方法。该方法将PDN结构划分为单独组件,用电磁工具和公式计算提取无源电阻、电感、电容参数后,按组件位置组装成等效电路模型。通过与三维全波仿真自阻抗曲线比较对模型进行了验证,并基于模型,用ADS研究了模组位置排布、垂直互连密度、芯片功耗及去耦电容对电压降(IR-drop)的影响。结果表明:模型自阻抗曲线与三维全波仿真基本吻合;在一定范围内,合理排布模组位置、增加垂直互连密度、减少芯片功耗、使用较大去耦电容能降低IR-drop,为晶上系统设计和制造提供了参考。

基于粗糙集理论和正交设计的冠心苏合滴丸制药生产工艺参数优选的方法研究

目的利用粗糙集理论和正交设计研究制药生产工艺参数之间的规律,探求优选生产工艺参数优选的数学方法。方法采用粗糙集理论方法,以冠心苏合滴丸生产工艺参数优选为案例,利用正交设计试验预处理数据,建立决策表,通过粗糙集规则模型动态分析工艺参数对结果的影响,优选最佳工艺参数。结果当冠心苏合滴丸生产工艺的参数药物与基质的配比分别与药液温度和冷却剂温度的水平逐渐增高时,溶散时限的平均水平呈现低-高-低的动态变化趋势;但当药液温度和冷却剂温度水平逐渐增高时,溶散时限的平均水平呈现动态的递减变化趋势。药物与基质的配比为1∶2,药液温度为70℃,冷却剂温度为12~14℃时,为冠心苏合滴丸生产工艺的参数的最佳组合。结论粗糙集理论能够动态、全面地分析制药生产工艺参数与试验指标之间的内在关系,提供了一种研究提高制药生产工艺质量的数学方法。

磁悬浮轴承系统跌落转子-保护轴承的动态响应分析

保护轴承是磁悬浮轴承系统发生失稳、掉电等故障后保护系统的重要部件,其动态性能直接影响磁悬浮轴承系统的安全性和可靠性。通过有限元软件Abaqus和舍弗勒轴承动力学软件Caba3D建立了柔性转子和保护轴承的动力学模型,开展了从转子开始跌落到转子-保护轴承系统相对稳定状态的动态响应研究,分析了转子和保护轴承内圈转速、转子质心轨迹、转子与保护轴承内圈的碰撞力、球之间的碰撞力、球与内圈之间滑动速度随时间的变化过程。结果表明:在转子的驱动下,保护轴承内圈转速先以极高的加速度升高,当内圈转速与转子接近时,转子和内圈转速又以极低的减速度降低;当保护轴承内圈加速时,转子的质心轨迹紊乱,转子与内圈的碰撞力较大,并且内圈与球之间的滑动速度随着时间增加逐渐增加;当保护轴承内圈减速时,转子与内圈的碰撞力较小,并且内圈与球之间的滑动速度随着时间增加逐渐降低。

基于Gamma混合模型的出租车落客行为

为了更好地理解枢纽送站坪出租车落客行为,提高落客区域通行效率,提出基于Gamma混合模型的出租车落客决策模型.应用精确的出租车轨迹数据,将出租车停车时间分解为主动停车时间、被迫停车时间和落客时间,基于被迫停车时间分析构建等待耐性混合分布模型,模型验证结果与真实数据相吻合.在此基础上,以潜在乘客耐心分布、停车位置、期望停车位和行程时间为落客决策模型的核心指标,提取相关因子为解释变量,以是否落客为被解释变量,构建二元面板Logit模型,并对模型进行检验.结果表明,乘客耐心对车辆落客起着决定性的作用,落客决策模型预测准确率超过81%,表明该模型能够较好地预测出租车落客行为,为研究缓堵策略提供基础.

某型飞机投水作动系统建模与同步性仿真分析

提高某型飞机投水舱门的同步性是保证灭火任务顺利完成的关键。为了开展多参数对收放作动筒同步性影响的研究工作,首先,基于投水灭火流程和投水作动系统液压原理,通过AMESim的液压元件库、逻辑库和状态机,建立了投水作动系统仿真模型。其次,通过连续投水工况仿真模拟,进行投水作动系统方案的功能性能分析,从而验证了仿真模型符合某型投水飞机工况性能要求。最后,通过批处理模式探究各敏感参数对多投水舱门收放作动筒的同步性影响。仿真表明:投水作动系统仿真模型可以实现多系统、多模式等不同任务和功能的仿真分析,电磁阀流量、负载、舱门作动筒活塞杆直径和管路直径对多缸同步性有着明显影响。

水滴形大跨钢屋盖结构风洞试验和风振分析

自然风经过大跨结构时,由于结构屋顶形状不规则,通常会引起柔性屋面的振动,因此针对大跨屋面结构抗风设计需要考虑风压分布和风振响应。以陕西省水务集团矿泉水生产车间为工程背景,制作了1∶200的刚性模型,通过刚性模型风洞试验测得该水滴型大跨钢屋盖结构的表面风压,研究了屋盖表面典型测点及整体的风压分布规律。基于风洞试验数据,对结构进行风振时程分析,得到了屋盖表面的风振响应和风振系数。结合刚性模型风洞试验和风振分析,深入研究了水滴形大跨屋盖结构的风压分布规律和风致振动特性,并总结了其共性规律。

液氮灭火系统管路输送压力损失影响因素及计算方法研究

结合液氮防灭火工程管路实际,分析了环境温度、液氮温度、入口流速、管长、管径、出口口径对管路出口液氮含量、输送压降的影响,并结合模拟与试验分析了均相模型预测管路输送压降的计算方法。结果表明:环境温度、液氮温度对液氮含量和管路压降影响较小;管路流速越快、输送距离越长、管径越小,压降增加越显著;随管路出口口径的减小压降迅速增加。对于低干度的气液两相氮适合用于均相模型计算,提出的简化计算经验模型压降预测值与试验值吻合良好,可以预测气液两相氮的管路输送压降,为液氮输送管路的工程应用设计提供理论支撑。

空降车辆着陆缓冲过程仿真分析与模型验证

围绕空降车辆在着陆缓冲过程中的冲击载荷,建立空降车辆-缓冲气囊耦合有限元模型并开展着陆缓冲过程仿真.开展典型垂直降落工况地面跌落模拟试验,对比仿真数据与试验实测数据,验证仿真模型的准确性.对垂直降落工况和水平向速度的着陆缓冲过程开展仿真分析,校核车辆冲击载荷、反弹速度、气囊内压等着陆缓冲响应.仿真结果表明,对于某空降车辆,目前的空降车辆-缓冲气囊设计方案在多种工况下的冲击载荷满足使用要求.此种方法可以较好满足空降车辆方案优化和着陆缓冲性能预测.

天然气过滤分离器全生命周期成本优化

过滤分离器是脱除天然气中固体颗粒、液体杂质等的重要设备。通过对滤芯压降与天然气流量、粉尘累计量的关系分析,综合考虑壳体加工、滤芯更换、运行能耗成本和更换滤芯时排放天然气、惰性气体置换等操作成本,建立了过滤分离器全生命周期成本数学模型和分析计算方法。实例计算表明:运行能耗成本是生产成本的重要组成部分,所占比重较大,终止压降0.12 MPa时运行能耗成本为总成本的80%左右;以全生命周期成本最低为目标,存在最优滤芯数量和设备规格以及最优滤芯更换周期。利用数学模型对设备进行全生命周期全面、系统地优化分析,指导设备设计和运行管理,可以节约能源和资源。

融合模型在铁钢界面铁水温度预测中的应用研究

铁钢界面是连接炼铁与炼钢间的重要工序,及时掌握铁水温度变化,提前半小时得到鱼雷罐车中铁水温度范围区间对于现场后续工作有很强的指导性,准确预测铁钢界面铁水温度对实现铁钢界面极致减碳和降本增效具有重要意义。为解决机理模型在铁钢界面预测铁水温度的局限性,基于某国内钢铁企业铁钢界面实际数据开发多种数据模型预测铁水温度,与机理模型相比,数据模型整体命中率提高1.13%。根据铁水转运过程中传热学特征和现场实际情况,将机理模型和数据模型融合形成串联模型和并联模型预测铁水温度,串联模型在实际应用过程中整体命中率为93.89%,并联模型整体命中率为94.26%高于其他模型。