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Effects of rotor and stator geometry on dissolution process and power consumption in jet-flow high shear

Lin Yang, Wenpeng Li, Junheng Guo, Wei Li, Baoguo Wang, Minqing Zhang, Jinli Zhang

《化学科学与工程前沿（英文）》 2021年 第15卷 第2期   页码 384-398 doi: 10.1007/s11705-020-1928-7

摘要： The jet-flow high shear mixer (JF-HSM) is a new type of intensified equipment with special configurations of the rotor and the stator. The mass transfer property and power consumption were studied in the solid-liquid system for a series of JF-HSMs involving different configuration parameters, such as rotor diameter, rotor blade inclination, rotor blade bending direction, stator diameter, and stator bottom opening diameter. The flow characteristics were examined by computational fluid dynamic simulations. Results indicate that the turbulent power consumption of the JF-HSM is affected by the change in rotor blade inclination and stator bottom opening. With the increase in the shear head size and the change in the rotor into a backward-curved blade, the solid-liquid mass transfer rate can be remarkably increased under the same input power. Dimensionless correlations for the mass transfer coefficient and power consumption were obtained to guide the scale-up design and selection of such a new type of equipment to intensify the overall mixing efficiency.

关键词： jet-flow high shear mixer     solid particle dissolution     power consumption characteristics     CFD Simulation    

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Micromixing performance of the teethed high shear mixer under semi-batch operation

《化学科学与工程前沿（英文）》 2022年 第16卷 第4期   页码 546-559 doi: 10.1007/s11705-021-2069-3

摘要： Semi-batch operated reaction processes are necessary for some competitive reaction systems to achieve a desirable process selectivity and productivity of fine chemical products. Herein the structural and operating parameters of the teethed high shear mixers were adjusted to study the micromixing performance in the semi-batch operated system, using the Villermaux/Dushman reaction system. The results indicate that the rising of the rotor speed and the number of rotor teeth, the decrease of the width of the shear gap and the radial distance between the feed position and the inner wall of stator can enhance the micromixing level and lead to the decrease of the segregation index. Additionally, computational fluid dynamics calculations were carried out to disclose the evolution of the flow pattern and turbulent energy dissipation rate of the semi-batch operated high shear mixer. Furthermore, the correlation was established with a mean relative error of 8.05% and R2 of 0.955 to fit the segregation index and the parameters studied in this work, which can provide valuable guidance on the design and optimization of the semi-batch operated high shear mixers in practical applications.

关键词： high shear mixer     semi-batch operation     micromixing performance     Villermaux/Dushman system     segregation index    

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Convective mass transfer from a horizontal rotating cylinder in a slot air jet flow

Hongting MA , Dandan MA , Na YANG ,

《能源前沿（英文）》 2009年 第3卷 第3期   页码 289-296 doi: 10.1007/s11708-009-0019-8

摘要： The effects of air jet impinging on the mass transfer characteristics from a rotating spinning cylinder surface were experimentally investigated. The effects of rotational Reynolds number

关键词： air jet impinging     rotating cylinder     critical point     mass transfer characteristics    

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水射流技术在石油工程中的应用及前景展望

沈忠厚,李根生,王瑞和

《中国工程科学》 2002年 第4卷 第12期   页码 60-65

摘要：

论述了水射流技术在我国石油工程中的研究和应用情况。应用实验方法建立了淹没非自由射流压力及水功率衰减计算模型，建立了以井底获得最大水功率，优选水力参数设计的新方法和新模型。应用瞬态流理论及水声学原理建立了两种谐振腔的基本关系式和结构数学模型。建立了在钻井双向应力作用下，岩石裂纹发展方向模型。介绍了研制的3种新型高效钻头，即加长喷嘴牙轮钻头、自振射流钻头和射流及机械联合破岩钻头。展望了水射流技术在超高压射流钻井、稠油及低渗油藏开采、提高采收率等方面的应用前景。

关键词： 水射流技术     石油钻井     油气开采     高压和超高压射流    

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Slender reinforced concrete shear walls with high-strength concrete boundary elements

《结构与土木工程前沿（英文）》 2023年 第17卷 第1期   页码 138-151 doi: 10.1007/s11709-022-0897-y

摘要： Reinforced concrete structural walls are commonly used for resisting lateral forces in buildings. Owing to the advancements in the field of concrete materials over the past few decades, concrete mixes of high compressive strength, commonly referred to as high-strength concrete (HSC), have been developed. In this study, the effects of strategic placement of HSC on the performance of slender walls were examined. The finite-element model of a conventional normal-strength concrete (NSC) prototype wall was validated using test data available in extant studies. HSC was incorporated in the boundary elements of the wall to compare its performance with that of the conventional wall at different axial loads. Potential reductions in the reinforcement area and size of the boundary elements were investigated. The HSC wall exhibited improved strength and stiffness, and thereby, allowed reduction in the longitudinal reinforcement area and size of the boundary elements for the same strength of the conventional wall. Cold joints resulting from dissimilar concrete pours in the web and boundary elements of the HSC wall were modeled and their impact on behavior of the wall was examined.

关键词： slender walls     high-strength concrete     rectangular and barbell-shaped walls     cold joints    

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Behavior and strength of headed stud shear connectors in ultra-high performance concrete of composite

Jianan QI, Yuqing HU, Jingquan WANG, Wenchao LI

《结构与土木工程前沿（英文）》 2019年 第13卷 第5期   页码 1138-1149 doi: 10.1007/s11709-019-0542-6

摘要： This study presents an experimental and numerical investigation on the static behavior of headed stud shear connectors in ultra-high performance concrete (UHPC) of composite bridges. Four push-out specimens were tested. It was found that no cracking, crushing or splitting was observed on the concrete slab, indicating that UHPC slab exhibited good performance and could resist the high force transferred from the headed studs. The numerical and experimental results indicated that the shear capacity is supposed to be composed of two parts stud shank shear contribution and concrete wedge block shear contribution. The stiffness increment of a stud in UHPC was at least 60% higher than that in normal strength concrete. Even if the stud height was reduced from 6 to 2 , there was no reduction in the shear strength of a stud. Short stud shear connectors with an aspect ratio as small as 2 could develop full strength in UHPC slabs. An empirical load-slip equation taking into account stud diameter was proposed to predict the load-slip response of a stud. The reliability and accuracy of the proposed load-slip equation was verified by the experimental and numerical load-slip curves.

关键词： ultra-high performance concrete     studs     shear strength     FE analysis     push-out test    

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Combined static mixers for high viscous fluids mixing

Zhenhao XI, Weizhen SUN, Ling ZHAO, Zhaoyan LIU

《化学科学与工程前沿（英文）》 2009年 第3卷 第1期   页码 93-96 doi: 10.1007/s11705-009-0112-x

摘要： A new static mixer Cross-over-Disc has been invented to strip off the boundary layer and to make strong radial mixing. The pressure drop of Cross-over-Disc is 12—26 times as large as that of empty pipe with equivalent diameter and length. The mixing performance of Cross-over-Disc with 14 elements has been investigated in the viscosity range of 190—250 Pa?s by decoloration method, and the gray analysis of images shows that mixing inhomogeneity is about 7.5% and 9.4% for the mixing ratio of 5∶1 and 10∶1, respectively. Furthermore, mixing inhomogeneity for a combination of static mixing elements (four from Cross-over-Disc and three pairs from Sulzer-type) can be decreased to 2.1%—3.1% within a reasonable range of pressure drop.

关键词： static mixer     Cross-over-Disc     pressure drop     mixing performance     high viscous fluid    

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Flexural and longitudinal shear performance of precast lightweight steel–ultra-high performance concrete

《结构与土木工程前沿（英文）》 2023年 第17卷 第5期   页码 704-721 doi: 10.1007/s11709-023-0941-6

摘要： In this study, the flexural and longitudinal shear performances of two types of precast lightweight steel–ultra-high performance concrete (UHPC) composite beams are investigated, where a cluster UHPC slab (CUS) and a normal UHPC slab (NUS) are connected to a steel beam using headed studs through discontinuous shear pockets and full-length shear pockets, respectively. Results show that the longitudinal shear force of the CUS is greater than that of the NUS, whereas the interfacial slip of the former is smaller. Owing to its better integrity, the CUS exhibits greater flexural stiffness and a higher ultimate bearing capacity than the NUS. To further optimize the design parameters of the CUS, a parametric study is conducted to investigate their effects on the flexural and longitudinal shear performances. The square shear pocket is shown to be more applicable for the CUS, as the optimal spacing between two shear pockets is 650 mm. Moreover, a design method for transverse reinforcement is proposed; the transverse reinforcement is used to withstand the splitting force caused by studs in the shear pocket and prevent the UHPC slab from cracking. According to calculation results, the transverse reinforcement can be canceled when the compressive strength of UHPC is 150 MPa and the volume fraction of steel fiber exceeds 2.0%.

关键词： precast steel–UHPC composite beam     flexural performance     longitudinal shear performance     parametric study     transverse reinforcement ratio    

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脉冲水射流水力共振设计

蒲家宁,陈明

《中国工程科学》 2009年 第11卷 第2期   页码 36-42

摘要：

在导管首端设置正弦脉冲流发生器，下游某处设置空气室，精心构建系统条件造成水力共振，使喷 嘴处脉冲射流的压力振幅大大提高。系统的数学物理模型用水力瞬变特征线有限差分方程建立，变时步方法解算。最优水力共振条件用Matlab直接搜索算法搜寻。正弦脉冲流发生器由恒流泵和正弦容积变化活塞 缸构成，电动活塞泵用凸轮传动给出恒定流量，活塞缸活塞用凸轮或曲轴连杆传动使缸容正弦变化。

关键词： 脉冲水射流     水力共振     特征线解法     变时步法     Matlab     直接搜寻算法     正弦脉冲流发生器    

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Shear behavior of ultra-high-performance concrete beams prestressed with external carbon fiber-reinforced

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1426-1440 doi: 10.1007/s11709-021-0783-z

摘要： The ultra-high-performance concrete (UHPC) and fiber-reinforced polymer (FRP) are well-accepted high-performance materials in the field of civil engineering. The combination of these advanced materials could contribute to improvement of structural performance and corrosion resistance. Unfortunately, only limited studies are available for shear behavior of UHPC beams reinforced with FRP bars, and few suggestions exist for prediction methods for shear capacity. This paper presents an experimental investigation on the shear behavior of UHPC beams reinforced with glass FRP (GFRP) and prestressed with external carbon FRP (CFRP) tendons. The failure mode of all specimens with various shear span to depth ratios from 1.7 to 4.5 was diagonal tension failure. The shear span to depth ratio had a significant influence on the shear capacity, and the effective prestressing stress affected the crack propagation. The experimental results were then applied to evaluate the equations given in different codes/recommendations for FRP-reinforced concrete structures or UHPC structures. The comparison results indicate that NF P 18-710 and JSCE CES82 could appropriately estimate shear capacity of the slender specimens with a shear span to depth ratio of 4.5. Further, a new shear design equation was proposed to take into account the effect of the shear span to depth ratio and the steel fiber content on shear capacity.

关键词： beam     external prestressing     ultra-high-performance concrete     fiber-reinforced polymers     shear behavior     design equation    

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独头巷道受限贴附射流流场特征模拟实验研究

王海桥,刘荣华,陈世强

《中国工程科学》 2004年 第6卷 第8期   页码 45-49

摘要：

独头巷道压入式通风是有限空间的受限贴附射流。基于流体动力学和射流理论，建立了独头巷道压入式受限贴附射流通风的紊流k-ε数学模型，分析了计算边界条件，并应用PHOENICS3.4计算流体动力学(CFD)软件模拟了独头巷道射流通风三维流场，得出了独头巷道有限空间受限贴附射流通风流场分区、射流起始段、射流贴附过程及射流流速变化规律等流场特征。模拟计算结果表明，独头巷道压入式通风流场可分为贴附射流区、冲击射流贴附区、回流区和涡流区，受限贴附射流起始段小于贴附自由射流起始段。射流完全贴附后，射流壁面轴心速度大于出风口轴心速度。数值模拟与实验结果相符，为研究独头巷道风流传质过程、瓦斯运移规律及通风排污效率等提供了理论基础。

关键词： 独头巷道     受限贴附射流     k-ε模型     数值计算    

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Stability of an annular viscous liquid jet in compressible gases with different properties inside andoutside of the jet

Chunji YAN, Maozhao XIE,

《能源前沿（英文）》 2010年 第4卷 第2期   页码 198-204 doi: 10.1007/s11708-009-0054-5

摘要： A spatial linear instability analysis is conducted on an annular viscous liquid jet injected into compressible gases and a three-dimensional model of the jet is developed. The model takes into account differences between the velocities, densities of the gases inside and outside of the liquid jet. Theoretical analysis reveals that there exist 9 dimensionless parameters controlling the instability of the liquid jet. Numerical computations reveal some basic characteristics in the breakup and atomization process of the liquid jet as well as influences of these relevant parameters. Major observations and findings of this study are as follows. The Mach number plays a destabilizing role and the inner Mach number has a greater effect on the jet instability than the outer Mach number. The Reynolds number always tends to promote the instabilities of the liquid jet, but its influence is very limited. The Weber number and the gas-to-liquid density ratio also have unstable effects and can improve the atomization of liquid jets. Furthermore, the effects of the Weber number and gas-to-liquid density ratio on the maximum growth rates of axisymmetric and non-axisymmetric disturbances and corresponding dominant wave numbers are manifested in a linear way, while that of the Mach number is non-linear. The effect of Reynolds on the maximum growth rates is non-linear, but the dominant wavenumber is almost not affected by the Reynolds number.

关键词： liquid jet     dominant wave number     compressibility     instability    

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Shear design of high strength concrete prestressed girders

Emad L. LABIB,Hemant B. DHONDE,Thomas T. C. HSU,Y. L. MO

《结构与土木工程前沿（英文）》 2014年 第8卷 第4期   页码 373-387 doi: 10.1007/s11709-014-0087-7

摘要： Normal strength prestressed concrete I-girders are commonly used as the primary superstructure components in highway bridges. However, shear design guidelines for high strength PC girders are not available in the current structural codes. Recently, ten 7.62 m (25 feet) long girders made with high strength concrete were designed, cast, and tested at the University of Houston (UH) to study the ultimate shear strength and the shear concrete contribution ( ) as a function of concrete strength ( ). A simple semi-empirical set of equations was developed based on the test results to predict the ultimate shear strength of prestressed concrete I-girders. The UH-developed set of equations is a function of concrete strength ( ), web area ( ), shear span to effective depth ratio ( / ), and percentage of transverse steel ( ). The proposed UH-Method was found to accurately predict the ultimate shear strength of PC girders with concrete strength up to 117 MPa (17000 psi) ensuring satisfactory ductility. The UH-Method was found to be not as overly conservative as the ACI-318 (2011) code provisions, and also not to overestimate the ultimate shear strength of high strength PC girders as the AASHTO LRFD (2010) code provisions. Moreover, the proposed UH-Method was found fairly accurate and not exceedingly conservative in predicting the concrete contribution to shear for concrete strength up to 117 MPa (17000 psi).

关键词： shear design     high strength concrete     prestressed girders     full-scale tests    

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Experimental investigation of multiphase flow behavior in drilling annuli using high speed visualization

Alap Ali ZAHID, Syed Raza ur REHMAN, Anwarul HASAN, S. RUSHD, Mohammad Azizur RAHMAN

《能源前沿（英文）》 2020年 第14卷 第3期   页码 635-643 doi: 10.1007/s11708-018-0582-y

摘要： Imaging with high definition video camera is an important technique to visualize the drilling conditions and to study the physics of complex multiphase flow associated with the hole cleaning process. The main advantage of visualizing multiphase flow in a drilling annulus is that the viewer can easily distinguish fluid phases, flow patterns and thicknesses of cutting beds. In this paper the hole cleaning process which involves the transportation of cuttings through a horizontal annulus was studied. The two-phase (solid-liquid) and the three-phase (solid-liquid-gas) flow conditions involved in this kind of annular transportation were experimentally simulated and images were taken using a high definition camera. Analyzing the captured images, a number of important parameters like velocities of different phases, heights of solid beds and sizes of gas bubbles were determined. Two different techniques based on an image analysis software and MATLAB coding were used for the determinations. The results were compared to validate the image analyzing methodology. The visualization technique developed in this paper has a direct application in investigating the critical conditions required for efficient hole cleaning as well as in optimizing the mud program during both planning and operational phases of drilling. Particularly, it would be useful in predicting the cuttings transport performance, estimating solid bed height, gas bubble size, and mean velocities of bubbles/particles.

关键词： visualization     horizontal annulus     hole cleaning     multiphase flow     image analysis     flow regime    

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Combustion and emissions of RP-3 jet fuel and diesel fuel in a single-cylinder diesel engine

《能源前沿（英文）》 2023年 第17卷 第5期   页码 664-677 doi: 10.1007/s11708-021-0787-3

摘要： The combustion characteristics and emission behaviors of RP-3 jet fuel were studied and compared to commercial diesel fuel in a single-cylinder compression ignition (CI) engine. Engine operational parameters, including engine load (0.6, 0.7, and 0.8 MPa indicating the mean effective pressure (IMEP)), the exhaust gas recirculation (EGR) rate (0%, 10%, 20%, and 30%), and the fuel injection timing (−20, −15, −10, and −5 ° crank angle (CA) after top dead center (ATDC)) were adjusted to evaluate the engine performances of RP-3 jet fuel under changed operation conditions. In comparison to diesel fuel, RP-3 jet fuel shows a retarded heat release and lagged combustion phase, which is more obvious under heavy EGR rate conditions. In addition, the higher premixed combustion fraction of RP-3 jet fuel leads to a higher first-stage heat release peak than diesel fuel under all testing conditions. As a result, RP-3 jet fuel features a longer ignition delay (ID) time, a shorter combustion duration (CD), and an earlier CA50 than diesel fuel. The experimental results manifest that RP-3 jet fuel has a slightly lower indicated thermal efficiency (ITE) compared to diesel fuel, but the ITE difference becomes less noticeable under large EGR rate conditions. Compared with diesel fuel, the nitrogen oxides (NOx) emissions of RP-3 jet fuel are higher while its soot emissions are lower. The NOx emissions of RP-3 can be effectively reduced with the increased EGR rate and delayed injection timing.

关键词： RP-3 jet fuel     diesel     engine     combustion     emissions    

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标题 作者 时间 类型 操作

Effects of rotor and stator geometry on dissolution process and power consumption in jet-flow high shear

Lin Yang, Wenpeng Li, Junheng Guo, Wei Li, Baoguo Wang, Minqing Zhang, Jinli Zhang

期刊论文

Micromixing performance of the teethed high shear mixer under semi-batch operation

期刊论文

Convective mass transfer from a horizontal rotating cylinder in a slot air jet flow

Hongting MA , Dandan MA , Na YANG ,

期刊论文

水射流技术在石油工程中的应用及前景展望

沈忠厚,李根生,王瑞和

期刊论文

Slender reinforced concrete shear walls with high-strength concrete boundary elements

期刊论文

Behavior and strength of headed stud shear connectors in ultra-high performance concrete of composite

Jianan QI, Yuqing HU, Jingquan WANG, Wenchao LI

期刊论文

Combined static mixers for high viscous fluids mixing

Zhenhao XI, Weizhen SUN, Ling ZHAO, Zhaoyan LIU

期刊论文

Flexural and longitudinal shear performance of precast lightweight steel–ultra-high performance concrete

期刊论文

脉冲水射流水力共振设计

蒲家宁,陈明

期刊论文

Shear behavior of ultra-high-performance concrete beams prestressed with external carbon fiber-reinforced

期刊论文

独头巷道受限贴附射流流场特征模拟实验研究

王海桥,刘荣华,陈世强

期刊论文

Stability of an annular viscous liquid jet in compressible gases with different properties inside andoutside of the jet

Chunji YAN, Maozhao XIE,

期刊论文

Shear design of high strength concrete prestressed girders

Emad L. LABIB,Hemant B. DHONDE,Thomas T. C. HSU,Y. L. MO

期刊论文

Experimental investigation of multiphase flow behavior in drilling annuli using high speed visualization

Alap Ali ZAHID, Syed Raza ur REHMAN, Anwarul HASAN, S. RUSHD, Mohammad Azizur RAHMAN

期刊论文

Combustion and emissions of RP-3 jet fuel and diesel fuel in a single-cylinder diesel engine

期刊论文