Search | Engineering

订阅投稿

首页工程期刊工程焦点工程成就工程前沿关于我们 English

资源类型

期刊论文 230

会议视频 4

会议信息 1

年份

2024 1

2023 23

2022 18

2021 26

2020 19

2019 13

2018 12

2017 9

2016 10

2015 6

2014 5

2013 9

2012 9

2011 8

2010 13

2009 10

2008 13

2007 5

2006 3

2005 4

展开︾

关键词

Cu(In 4

薄膜润滑 4

Ga)Se₂ 3

柔性机器人 2

液体燃料 2

绿色化工 2

N-糖组 1

CCD影像 1

CCS 1

CO2 加氢 1

CO₂分离 1

Ga)Se₂光伏组件 1

N-聚糖 1

Ni–Ti–Cu–V合金 1

PDT 1

TOC 1

TRIZ 1

VO₂薄膜 1

[BMIm]PF6 1

展开︾

检索范围：

排序：展示方式：

Experimental study on combined buoyant-thermocapillary flow along with rising liquid film on the surface

Manuel J. GOMES, Ning MEI

《能源前沿（英文）》 2020年第14卷第1期页码 114-126 doi: 10.1007/s11708-017-0483-5

摘要： Temperature distribution and variation with time has been considered in the analysis of the influences of the initial level of immersion of a horizontal metallic mesh tube in the liquid on combined buoyant and thermo-capillary flow. The combined flow occurs along with the rising liquid film flow on the surface of a horizontal metallic mesh tube. Three different levels of immersion of the metallic mesh tube in the liquid have been tested. Experiments of 60 min in duration have been performed using a heating metallic tube with a diameter of 25 mm and a length of 110 mm, sealed outside with a metallic mesh of 178 mm by 178 mm, and distilled water. These reveal two distinct flow patterns. Thermocouples and infrared thermal imager are utilized to measure the temperature. The level of the liquid free surface relative to the lower edge of the tube is measured as angle . The results show that for a smaller angle, or a low level of immersion, with a relatively low heating power, it is possible to near fully combine the upwards buoyant flow with the rising liquid film flow. In this case, the liquid is heated only in the vicinity of the tube, while the liquid away from the flow region experiences small changes in temperature and the system approaches steady conditions. For larger angles, or higher levels of immersion, a different flow pattern is noticed on the liquid free surface and identified as the thermo-capillary (Marangoni) flow. The rising liquid film is also present. The higher levels of immersion cause a high temperature gradient in the liquid free surface region and promote thermal stratification; therefore the system could not approach steady conditions.

关键词： rising liquid film combined flow thermo-capillary flow buoyant flow metallic mesh tube horizontal tube

HTML PDF 收藏

Numerical simulation of liquid falling film on horizontal circular tubes

Fengdan SUN, Songlin XU, Yongchuan GAO

《化学科学与工程前沿（英文）》 2012年第6卷第3期页码 322-328 doi: 10.1007/s11705-012-1296-z

摘要： The objective of this study is to investigate numerically the flow characteristics of falling film on horizontal circular tubes. Numerical simulations are performed using FLUENT for 2D configurations with one and two cylinders. The volume of fluid method is used to track the motion of liquid falling film and the gas-liquid interface. The effect of flow characteristics on heat and transfer coefficient may be remarkable, although it has been neglected in previous studies. The velocity distribution and the film thickness characteristics on the top tube, some special flow characteristics on the bottom tube, intertube flow modes and effect of liquid feeder height on flow characteristics have been studied. Our simulations indicate that 1) the velocity distributions of the upper and lower parts of the tube are not strictly symmetric and non-uniform, 2) the film thickness depends on flow rate and angular distributions, 3) the flow characteristics of the top tube are different from those of the bottom tube, 4) three principal and two intermediate transition modes are distinguished, and 5) the liquid feed height plays an important role on the formation of falling film. The numerical results are in a good agreement with the theoretical values by the Nusselt model and the reported results.

关键词： falling film horizontal tube flow characteristics film thickness liquid feeder height

HTML PDF 收藏

Thin-liquid-film evaporation at contact line

Hao WANG, Zhenai PAN, Zhao CHEN

《能源前沿（英文）》 2009年第3卷第2期页码 141-151 doi: 10.1007/s11708-009-0020-2

摘要： When a liquid wets a solid wall, the extended meniscus near the contact line may be divided into three regions: a nonevaporating region, where the liquid is adsorbed on the wall; a transition region or thin-film region, where effects of long-range molecular forces (disjoining pressure) are felt; and an intrinsic meniscus region, where capillary forces dominate. The thin liquid film, with thickness from nanometers up to micrometers, covering the transition region and part of intrinsic meniscus, is gaining interest due to its high heat transfer rates. In this paper, a review was made of the researches on thin-liquid-film evaporation. The major characteristics of thin film, thin-film modeling based on continuum theory, simulations based on molecular dynamics, and thin-film profile and temperature measurements were summarized.

关键词： meniscus thin film contact line disjoining pressure evaporation

HTML PDF 收藏

Numerical studies of dynamic behavior of liquid film on single-layer wire mesh with different wettabilities

《化学科学与工程前沿（英文）》页码 1672-1680 doi: 10.1007/s11705-022-2205-8

摘要： Droplet impacting on the stainless steel wire mesh is very common in chemical devices, like a rotating packed bed. Surface wettability of wire mesh significantly affects the liquid flow pattern and liquid dispersion performance. However, the effect of surface wettability on the impaction phenomena at microscale such as liquid film is still unknown. In this work, the dynamic behavior of liquid film on the surface of wire mesh was analyzed by computational fluid dynamics simulation. The dynamic behavior of liquid film on the surface of wire mesh can be divided into the following three steps: (1) spreading step; (2) shrinkage process; (3) stabilizing or disappearing step. Effects of surface wettability, as well as operating conditions, on wetting area and liquid film thickness were studied. Compared to the hydrophilic wire mesh, the final wetting area of hydrophobic wire mesh is zero in most cases. The average liquid film thickness on the surface of hydrophilic wire mesh is 30.02–77.29 μm, and that of hydrophobic wire mesh is 41.76–237.37 μm. This work provided a basic understanding of liquid film flow at microscale on the surface with various surface wettabilities, which can be guiding the packing optimization and design.

关键词： stainless steel wire mesh computational fluid dynamics surface wettability liquid film impacting

HTML PDF 收藏

Water film coated composite liquid metal marble and its fluidic impact dynamics phenomenon

Yujie DING,Jing LIU

《能源前沿（英文）》 2016年第10卷第1期页码 29-36 doi: 10.1007/s11708-015-0388-0

摘要： A composite liquid metal marble made of metal droplet coated with water film was proposed and its impact dynamics phenomenon was disclosed. After encapsulating the liquid metal into water droplets, the fabricated liquid marble successfully avoided being oxygenized by the metal fluid and thus significantly improved its many physical capabilities such as surface tension modification and shape control. The striking behaviors of the composite liquid metal marbles on a substrate at room temperature were experimentally investigated in a high speed imaging way. It was disclosed that such marbles could disintegrate, merge, and even rebound when impacting the substrate, unlike the existing dynamic fluidic behaviors of liquid marble or metal droplet. The mechanisms lying behind these features were preliminarily interpreted. This fundamental finding raised profound multiphase fluid mechanics for understanding the complex liquid composite which was also critical for a variety of practical applications such as liquid metal jet cooling, inkjet printed electronics, 3D printing or metal particle fabrication etc.

关键词： liquid metal marble metallic droplet composite fluid impact dynamics multiphase fluid mechanics

HTML PDF 收藏

Effect of counter current gas phase on liquid film

Shujuan LUO, Huaizhi LI, Weiyang FEI, Yundong WANG

《化学科学与工程前沿（英文）》 2009年第3卷第2期页码 135-137 doi: 10.1007/s11705-009-0129-1

摘要： Liquid film flow is very important in many industrial applications. However, there are few reports about its characteristics on structured packings. Therefore, in this paper, liquid film phenomena were investigated experimentally to exploit new approaches for intensifying the performance of the structured packings. All experiments were performed at room temperature. Water and air were the working fluids. The effect of counter current gas phase on the liquid film was taken into consideration. A high speed camera, a non-intrusive measurement technique, was used. It is shown that both liquid and gas phases have strong effects on film characteristics. In the present work, liquid film width increased by 57% because of increasing liquid flow rate, while it decreased by 25% resulting from the counter current gas phase.

关键词： counter current liquid film two phases structured packings

HTML PDF 收藏

Ultrafast solid-liquid-vapor phase change of a thin gold film irradiated by femtosecond laser pulses

Jing HUANG, Yuwen ZHANG, J. K. CHEN, Mo YANG

《能源前沿（英文）》 2012年第6卷第1期页码 1-11 doi: 10.1007/s11708-012-0179-9

摘要： Effects of different parameters on the melting, vaporization and resolidification processes of thin gold film irradiated by femtosecond pulses and pulse train were systematically studied. The classical two-temperature model was adopted to depict the non-equilibrium heat transfer in electrons and lattice. The melting and resolidification processes, which was characterized by the solid-liquid interfacial velocity, as well as elevated melting temperature and depressed solidification temperature, was obtained by considering the interfacial energy balance and nucleation dynamics. Vaporization process which leads to ablation was described by tracking the location of liquid-vapor interface with an iterative procedure based on energy balance and gas kinetics law. The parameters in discussion included film thickness, laser fluence, pulse duration, pulse number, repetition rate, pulse train number, etc. Their effects on the maximum lattice temperature, melting depth and ablation depth were discussed based on the simulation results.

关键词： melting evaporation nucleation dynamics nanoscale heat transfer

HTML PDF 收藏

Synchronous observation of rising soluble bubble through quiescent solution

Yifu ZHANG , Shuai TIAN , Weizhong LI , Yongchen SONG ,

《能源前沿（英文）》 2009年第3卷第3期页码 307-312 doi: 10.1007/s11708-009-0028-7

摘要： An experimental method using computer image processing technology (CIPT) was proposed to observe and investigate the velocity, deformation, heat and mass transfer, etc. of a rising soluble gas (CO) bubble through a quiescent hot water. A model was set up to describe the behavior of the bubble in a visual experimental system in which a high-speed camera rose instantaneously with the movement of the bubble. A series of trajectory videos about the bubble were recorded by a computer linked to the camera. The trajectory, volume changes and rate of mass transfer of the bubble were obtained by the CIPT. It is found that the single bubble follows a rolling trajectory at the initial stage when there is mass transfer. With the volume decreasing, the disturbed behavior of the bubble becomes tempered. When the rising velocity of the bubble reaches the maximum, the velocity is nearly at a constant. The experimental and analysis results show that this method is useful for the research on the mass transfer and the movement of rising bubbles in liquid.

关键词： soluble bubble mass transfer synchronous observation computer image processing

HTML PDF 收藏

精密工程的重要性日益增加

Mark Hoffman, Liangchi Zhang

《工程（英文）》 2018年第4卷第6期页码 759-759 doi: 10.1016/j.eng.2018.11.007

HTML PDF 收藏

Experiment and optimal design of a collection device for a residual plastic film baler

Qi NIU,Xuegeng CHEN,Chao JI,Jie WU

《农业科学与工程前沿（英文）》 2015年第2卷第4期页码 347-354 doi: 10.15302/J-FASE-2015077

摘要： It is imperative to carry out research on residual plastic film collection technology to solve the serious problem of farmland pollution. The residual plastic film baler was designed as a package for film strip collection, cleaning and baling. The collection device is a core component of the baler. Response surface analysis was used in this study to optimize the structure and working parameters for improving the collection efficiency of residual film and the impurity of film package. The results show that the factors affecting the collection rate of residual film and the impurity of the film package are the speed ratio ( ) between the trash removal roller and eccentric collection mechanism, the number ( ) and the mounting angle ( ) of spring teeth in the same revolution plane. For the collection rate, the importance of the three factors are in the order, . Meanwhile, for the impurity, the importance of three factors are in the order, . When the speed ratio, the mounting angle and the number of spring teeth was set at 1.6°, 45°, and 8°, respectively, the collection rate of residual film was 88.9% and the impurity of residual film package was 14.2% for the baler.

关键词： residual film collection device collection rate of residual film impurity of film package optimization baler

HTML PDF 收藏

薄膜润滑研究的回顾与展望

雒建斌,张朝辉,温诗铸

《中国工程科学》 2003年第5卷第7期页码 84-89

摘要：

薄膜润滑是20世纪90年代以来广泛研究的新型润滑状态。它是界于弹流润滑和边界润滑之间的一种过渡润滑状态，有着自己独特的润滑规律。文章回顾了薄膜润滑的研究历史，包括薄膜润滑概念的提出、测试技术的发展、薄膜润滑的膜厚特性、润滑机理探索以及计算理论等方面的研究成果与主要进展。

关键词：薄膜润滑有序膜膜厚测量微结构

HTML PDF 收藏

Chemical probe systems for assessing liquid–liquid mixing efficiencies of reactors

《化学科学与工程前沿（英文）》 2023年第17卷第10期页码 1323-1335 doi: 10.1007/s11705-022-2275-7

摘要： Liquid–liquid mixing, including homogeneous and heterogeneous mixing, widely exists in the chemical industry. How to quantitatively characterize the mixing performance is important for reactor assessment and development. As a convenient and direct method for mixing characterization, the chemical probe method uses some special test reactions to characterize the mixing results. Here, the working principle and selection requirements of this method are introduced, and some common chemical probe systems for homogeneous and heterogeneous mixing processes are reviewed. The characteristics and applications of these systems are illustrated. Finally, the development of the new system is proposed.

关键词： mixing chemical probe liquid–liquid heterogeneous

HTML PDF 收藏

Surface-tailoring chlorine resistant materials and strategies for polyamide thin film composite reverse

《化学科学与工程前沿（英文）》 2022年第16卷第5期页码 564-591 doi: 10.1007/s11705-021-2109-z

摘要： Polyamide thin film composite membranes have dominated current reverse osmosis market on account of their excellent separation performances compared to the integrally skinned counterparts. Despite their very promising separation performance, chlorine-induced degradation resulted from the susceptibility of polyamide toward chlorine attack has been regarded as the Achilles’s heel of polyamide thin film composite. The free chlorine species present during chlorine treatment can impair membrane performance through chlorination and depolymerization of the polyamide selective layer. From material point of view, a chemically stable membrane is crucial for the sustainable application of membrane separation process as it warrants a longer membrane lifespan and reduces the cost involved in membrane replacement. Various strategies, particularly those involved membrane material optimization and surface modifications, have been established to address this issue. This review discusses membrane degradation by free chlorine attack and its correlation with the surface chemistry of polyamide. The advancement in the development of chlorine resistant polyamide thin film composite membranes is reviewed based on the state-of-the-art surface modifications and tailoring approaches which include the in situ and post-fabrication membrane modifications using a broad range of functional materials. The challenges and future directions in this field are also highlighted.

关键词： reverse osmosis polyamide thin film composite membranes chlorine resistance surface modification

HTML PDF 收藏

Piezoelectric film-actuated motion platform with high resolution

HUA Shunming, ZHANG Hongzhuang, CHENG Guangming, FAN Zunqiang, LIU Jianfang

《机械工程前沿（英文）》 2008年第3卷第3期页码 265-269 doi: 10.1007/s11465-008-0041-2

摘要： A piezoelectric film-actuated motion platform with high resolution, which can run in two directions within a horizontal plane, is presented. On the basis of the analysis of the working principle of a stick-slip mechanism, a mathematical model describing its dynamic behavior is set up and simulated. Experiments of the motion performance and carrying ability on the prototype are conducted. Results show that this type of platform has advantages including a simple structure, small volume, light weight, stable step length, and large traveling range. When the driving voltage is less than 30 V, step error is less than 0.5 ?m. The carrying ability of the platform is terrific and about 7–8 times its weight.

关键词： mathematical stick-slip mechanism piezoelectric film-actuated analysis terrific

HTML PDF 收藏

Microfluidic production of liposomes through liquid–liquid phase separation in ternary droplets

《化学科学与工程前沿（英文）》 2022年第16卷第6期页码 1017-1022 doi: 10.1007/s11705-021-2118-y

摘要： Liposomes, the self-assembled phospholipid vesicles, have been extensively used in various fields such as artificial cells, drug delivery systems, biosensors and cosmetics. However, current microfluidic routes to liposomes mostly rely on water-in-oil-in-water double emulsion droplets as templates, and require complex fabrication of microfluidic devices, and tedious manipulation of multiphase fluids. Here we present a simple microfluidic approach to preparing monodisperse liposomes from oil-in-water droplets. For demonstration, we used butyl acetate-water-ethanol ternary mixtures as inner phase and an aqueous solution of surfactants as outer phase to make oil-in-water droplets, which can evolve into water-in-oil-in-water double emulsion droplets by liquid–liquid phase separation of ternary mixtures. Subsequently, the resultant water-in-oil-in-water droplets underwent a dewetting transition to form separated monodisperse liposomes and residual oil droplets, with the assistance of surfactants. The method is simple, does not require complex microfluidic devices and tedious manipulation, and provides a new platform for controllable preparation of liposomes.

关键词： microfluidics liposomes ternary droplets phase separation