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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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Pre-chamber turbulent jet ignition of methane/air mixtures with multiple orifices in a large bore constantvolume chamber: effect of air-fuel equivalence ratio and pre-mixed pressure

Xiang LI, Wenzheng ZHANG, Zhong HUANG, Dehao JU, Li HUANG, Mingzhi FENG, Xingcai LU, Zhen HUANG

《能源前沿（英文）》 2019年 第13卷 第3期   页码 483-493 doi: 10.1007/s11708-019-0631-1

摘要： Liquefied natural gas (LNG), mainly composed of methane, is in progress to substitute diesel fuel in heavy-duty marine engine for practical, economic, and environmental considerations. However, natural gas is relatively difficult to be ignited in a large bore combustion chamber. A combustion enhancement technique called pre-chamber turbulent jet ignition (TJI) can permit combustion and flame propagation in a large-bore volume. To investigate the effect of air-fuel equivalence ratio and pre-mixed pressure on pre-chamber TJI of methane/air mixtures with multiple orifices in a large bore volume, experimental tests and computational simulations were implemented to study the discharge of hot turbulent jets from six orifices of the pre-chamber. Different initial pressures and air-fuel equivalence ratios were considered to analyze the characteristics of TJI. The asymmetry of the turbulent jet actuated from six different orifices were found due to the asymmetric orientation of the spark plug, resulting in the inhomogeneous distribution of combustion in the constant volume chamber, which should be considered seriously in the marine engine design. Besides, as the premixed pressure increases, it has more effect on the flame propagation and plays a more important role, as it further increases.

关键词： marine engine     natural gas     methane     turbulent jet ignition (TJI)     pre-chamber    

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Characterization of micro-mixing in a novel impinging streams reactor

Hui HU, Zhiming CHEN, Zhen JIAO

《化学科学与工程前沿（英文）》 2009年 第3卷 第1期   页码 58-64 doi: 10.1007/s11705-009-0106-8

摘要： This paper presents an experimental investigation of a novel impinging stream reactor (ISR) with the aim of high mixing intensity. The integral mixing quality in the reactor was measured with the iodide-iodate reaction and showed excellent mixing performance. The impact of the operating parameters, such as fluxes, circulation and inter-nozzle distances, was investigated in terms of segregation index. The results showed that the increase of flux, the decrease of inter-nozzle distance and a suitable circulation can improve the micro-mixing efficiency. Based on turbulence theory, it was estimated that the characteristic micro-mixing time was 0.002—0.02 s, which was much shorter than that in the stirred tank reactor. The micro-mixing time was related to the segregation index, which was in good agreement with those in the literature.

关键词： micro-mixing     impinging streams reactor     turbulent mixing     mass transfer    

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考虑射流掺气的改进冲刷模型

Rafael Duarte,António Pinheiro,Anton J. Schleiss

《工程（英文）》 2016年 第2卷 第3期   页码 294-301 doi: 10.1016/J.ENG.2016.03.003

摘要：

基于受高速射流冲击的水垫塘中掺气对岩块稳定性影响的系统试验研究，本文给出了一种基于物理特性冲刷模型的适应性研究成果。在综合冲刷模型中实现了对射流掺气模型的改进，使其得以再现有关冲刷形成的物理– 机械过程，其中涉及三相，即水、岩体和空气。改进方法考虑了因挟带气泡引起的掺气射流动量减少以及射流扩散剪切层的能量消耗。岩块从岩体脱离取决于掺气的时均压强系数及修正的最大动力冲击系数的组合，对于深水垫塘中的高速射流，该系数为定值0.2。上述改进模型的模拟结果与卡里巴大坝冲坑原型观测结果吻合良好。

关键词： 掺气     上举力     岩体冲刷     大坝安全     高速射流     岩块稳定性     冲刷评估    

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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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Numerical study of droplet dynamics impinging onto steel plate covered with scale layer

Jan BOHá?EK, Ale? HORáK

《机械工程前沿（英文）》 2010年 第5卷 第4期   页码 389-398 doi: 10.1007/s11465-010-0108-8

摘要： The steel hot rolling process is inseparably connected to an oxide layer called “scale” at high temperatures. Hydraulic descaling of rolled material is a part of all rolling trains. Surface quality after descaling is fundamental for the final surface quality of a rolled product. The process itself is not theoretically well described; various different approaches have been used to clarify the descaling problem. This paper describes the dynamics of high-speed impact between the compressible water droplet and the steel scale layer. The phenomenon is known as water hammer effect. The purpose of this study is to numerically verify the fact that impact stress can be a significant factor during the descaling process. Considering a high droplet impact speed (100–300 ms ), inferential extremely short time interval (0.1–5 μs) peaks in impact pressure reaching 300 MPa can be found. Droplet dynamics was simulated with the help of LS-Dyna solver, whereas the stress analysis was performed in ANSYS interface. The extreme pressure peaks of very short duration in an impact area are a new phenomenon in the descaling theory.

关键词： hydraulic descaling     scale     rolling     water-hammer     descaling theory    

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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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Fabrication of micro/nano-structures by electrohydrodynamic jet technique

Dazhi WANG, Xiaojun ZHAO, Yigao LIN, Tongqun REN, Junsheng LIANG, Chong LIU, Liding WANG

《机械工程前沿（英文）》 2017年 第12卷 第4期   页码 477-489 doi: 10.1007/s11465-017-0461-y

摘要：

Electrohydrodynamic jet (E-Jet) is an approach to the fabrication of micro/nano-structures by the use of electrical forces. In this process, the liquid is subjected to electrical and mechanical forces to form a liquid jet, which is further disintegrated into droplets. The major advantage of the E-Jet technique is that the sizes of the jet formed can be at the nanoscale far smaller than the nozzle size, which can realize high printing resolution with less risk of nozzle blockage. The E-Jet technique, which mainly includes E-Jet deposition and E-Jet printing, has a wide range of applications in the fabrication of micro/nano-structures for micro/nano-electromechanical system devices. This technique is also considered a micro/nano-fabrication method with a great potential for commercial use. This study mainly reviews the E-Jet deposition/printing fundamentals, fabrication process, and applications.

关键词： electrohydrodynamic jet deposition     electrohydrodynamic jet printing     micro/nano-structures     film    

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Residence time distribution and modeling of the liquid phase in an impinging stream reactor

Xingjun WANG, Xianhui HU, Lishun HU, Guangsuo YU, Fuchen WANG,

《化学科学与工程前沿（英文）》 2010年 第4卷 第3期   页码 353-359 doi: 10.1007/s11705-009-0262-x

摘要： Based on some experimental investigations of liquid phase residence time distribution (RTD) in an impinging stream reactor, a two-dimensional plug-flow dispersion model for predicting the liquid phase RTD in the reactor was proposed. The calculation results of the model can be in good agreement with the experimental RTD under different operating conditions. The axial liquid dispersion coefficient increases monotonously with the increasing liquid flux, but is almost independent of gas flux. As the liquid flux and the gas flux increase, the liquid dispersion coefficient of center-to-wall decreases. The axial liquid dispersion coefficient is much larger than that of center-to-wall, which indicates that the liquid RTD is dominated mainly by axial liquid dispersion in the impinging stream reactor.

关键词： RTD     liquid dispersion     reactor     liquid     independent    

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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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Simulation of steel beam under ceiling jet based on a wind–fire–structure coupling model

《结构与土木工程前沿（英文）》 2023年 第17卷 第1期   页码 78-98 doi: 10.1007/s11709-022-0936-8

摘要： For localized fires, it is necessary to consider the thermal and mechanical responses of building elements subject to uneven heating under the influence of wind. In this paper, the thermomechanical phenomena experienced by a ceiling jet and I-beam in a structural fire were simulated. Instead of applying the concept of adiabatic surface temperature (AST) to achieve fluid–structure coupling, this paper proposes a new computational fluid dynamics–finite element method numerical simulation that combines wind, fire, thermal, and structural analyses. First, to analyze the velocity and temperature distributions, the results of the numerical model and experiment were compared in windless conditions, showing good agreement. Vortices were found in the local area formed by the upper and lower flanges of the I-beam and the web, generating a local high-temperature zone and enhancing the heat transfer of convection. In an incoming-flow scenario, the flame was blown askew significantly; the wall temperature was bimodally distributed in the axial direction. The first temperature peak was mainly caused by radiative heat transfer, while the second resulted from convective heat transfer. In terms of mechanical response, the yield strength degradation in the highest-temperature region in windless conditions was found to be significant, thus explaining the stress distribution of steel beams in the fire field. The mechanical response of the overall elements considering the incoming flows was essentially elastic.

关键词： CFD–FEM coupling     steel beam     wind     ceiling jet     numerical heat transfer    

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RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

《化学科学与工程前沿（英文）》 2023年 第17卷 第12期   页码 2161-2161 doi: 10.1007/s11705-009-0143-3

摘要： RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

关键词： tee junction     Momentum exchange coefficient     RETRACTED    

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An experimental study on spray auto-ignition of RP-3 jet fuel and its surrogates

Yaozong DUAN, Wang LIU, Zhen HUANG, Dong HAN

《能源前沿（英文）》 2021年 第15卷 第2期   页码 396-404 doi: 10.1007/s11708-020-0715-y

摘要： Jet fuel is widely used in air transportation, and sometimes for special vehicles in ground transportation. In the latter case, fuel spray auto-ignition behavior is an important index for engine operation reliability. Surrogate fuel is usually used for fundamental combustion study due to the complex composition of practical fuels. As for jet fuels, two-component or three-component surrogate is usually selected to emulate practical fuels. The spray auto-ignition characteristics of RP-3 jet fuel and its three surrogates, the 70% mol -decane/30% mol 1,2,4-trimethylbenzene blend (Surrogate 1), the 51% mol -decane/49% mol 1, 2, 4-trimethylbenzene blend (Surrogate 2), and the 49.8% mol -dodecane/21.6% mol -cetane/28.6% mol toluene blend (Surrogate 3) were studied in a heated constant volume combustion chamber. Surrogate 1 and Surrogate 2 possess the same components, but their blending percentages are different, as the two surrogates were designed to capture the H/C ratio (Surrogate 1) and DCN (Surrogate 2) of RP-3 jet fuel, respectively. Surrogate 3 could emulate more physiochemical properties of RP-3 jet fuel, including molecular weight, H/C ratio and DCN. Experimental results indicate that Surrogate 1 overestimates the auto-ignition propensity of RP-3 jet fuel, whereas Surrogates 2 and 3 show quite similar auto-ignition propensity with RP-3 jet fuel. Therefore, to capture the spray auto-ignition behaviors, DCN is the most important parameter to match when designing the surrogate formulation. However, as the ambient temperature changes, the surrogates matching DCN may still show some differences from the RP-3 jet fuel, e.g., the first-stage heat release influenced by low-temperature chemistry.

关键词： RP-3 jet fuel     surrogate     spray auto-ignition     constant volume combustion chamber    

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Formation of coke in thermal cracking of jet fuel under supercritical conditions

ZHU Yuhong, YU Caixiang, LI Zimu, MI Zhentao, ZHANG Xiangwen

《化学科学与工程前沿（英文）》 2008年 第2卷 第1期   页码 17-21 doi: 10.1007/s11705-008-0024-1

摘要： Continuous-flow reactor experiments were carried out to study coke formation from thermal cracking of home-made jet fuel RP-3 under supercritical conditions. The mechanism and precursor of coke forming were analyzed. The starting cracking temperature of RP-3 fuel was determined to be 471.8°C by differential scanning calorimetry (DSC). Temperature-programmed oxidation and scanning electron microscopy (SEM) characterizations of the stressed tubes showed that there are three different coke species including chemisorbed carbon, amorphous carbon and filamentous coke in the solid deposits. More than 90% of coke deposits are carried away by the supercritical fluid, which has strong capabilities of extraction for coke deposits and their precursors. There were 17.1 wt-% of iron and 11.1 wt-% of chromium found on the coke surface detected by energy dispersive spectroscopy (EDS) which suggests carburetion on alloy. RP-3 fuel and its cracking liquids were analyzed by GC-MS,which showed that the content of alkyl benzene and alkyl naphthalene increased evidently in cracking liquids.

关键词： dispersive spectroscopy     different     extraction     calorimetry     filamentous    

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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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标题 作者 时间 类型 操作

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

Hongting MA , Dandan MA , Na YANG ,

期刊论文

Pre-chamber turbulent jet ignition of methane/air mixtures with multiple orifices in a large bore constantvolume chamber: effect of air-fuel equivalence ratio and pre-mixed pressure

Xiang LI, Wenzheng ZHANG, Zhong HUANG, Dehao JU, Li HUANG, Mingzhi FENG, Xingcai LU, Zhen HUANG

期刊论文

Characterization of micro-mixing in a novel impinging streams reactor

Hui HU, Zhiming CHEN, Zhen JIAO

期刊论文

考虑射流掺气的改进冲刷模型

Rafael Duarte,António Pinheiro,Anton J. Schleiss

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

Numerical study of droplet dynamics impinging onto steel plate covered with scale layer

Jan BOHá?EK, Ale? HORáK

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

Fabrication of micro/nano-structures by electrohydrodynamic jet technique

Dazhi WANG, Xiaojun ZHAO, Yigao LIN, Tongqun REN, Junsheng LIANG, Chong LIU, Liding WANG

期刊论文

Residence time distribution and modeling of the liquid phase in an impinging stream reactor

Xingjun WANG, Xianhui HU, Lishun HU, Guangsuo YU, Fuchen WANG,

期刊论文

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

Simulation of steel beam under ceiling jet based on a wind–fire–structure coupling model

期刊论文

RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

期刊论文

An experimental study on spray auto-ignition of RP-3 jet fuel and its surrogates

Yaozong DUAN, Wang LIU, Zhen HUANG, Dong HAN

期刊论文

Formation of coke in thermal cracking of jet fuel under supercritical conditions

ZHU Yuhong, YU Caixiang, LI Zimu, MI Zhentao, ZHANG Xiangwen

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