期刊文献+
共找到14篇文章
< 1 >
每页显示 20 50 100
Test on methane flame velocity in horizontal tube with obstacles
1
作者 谭迎新 尉存娟 《Journal of Measurement Science and Instrumentation》 CAS 2012年第4期320-322,共3页
To test flame propagation velocity of gas explosion in a horizontal tube,a set of flame velocity testing system is designed.The system is composed of two parts:a horizontal tube used for methane burning and a flame de... To test flame propagation velocity of gas explosion in a horizontal tube,a set of flame velocity testing system is designed.The system is composed of two parts:a horizontal tube used for methane burning and a flame detection system.The effect of obstacles on flame propagation velocity of methane explosion is tested.Methane volume density is 10% in the tube.The obstacle is the circular ring,2 mm thick.Its blockage ratios are 40%,50% and 60%,respectively.The number of obstacles put in the tube is 1,3,5 and 7.Experimental results show that the obstacle has obviously accelerating effect on flame wave of gas explosion.As the number and blockage ratios of the obstacles increase,flame accelerating became more obviously.When there are seven obstacles,the maximum average flame velocity reaches over 351.2 m/s.When the blockage ratio of three obstacles is 60%,the maximum average flame velocity is 238.9 m/s. 展开更多
关键词 gas explosion OBSTACLE flame velocity horizontal tube METHANE
下载PDF
Thermal transfer experimental research of a horizontal tube evaporative condenser
2
作者 TU Ai-min, ZHU D.S. 《Journal of Chemistry and Chemical Engineering》 2007年第1期75-81,共7页
The thermal resistances distribution in different wet-bulb temperatures, air velocities and spraying water densities were achieved by the experimental test. The fluctuation of the water film convection and the water-a... The thermal resistances distribution in different wet-bulb temperatures, air velocities and spraying water densities were achieved by the experimental test. The fluctuation of the water film convection and the water-air interfacial thermal resistance were reviewed especially. In the distribution of thermal resistance, the rank of the thermal resistance proportion (from max to min) is air flow heat transfer resistance, heat transfer resistance between refrigerant and wall, water film convection resistance and wall heat transfer resistance. When the heat flux is constant, the total resistance lowers nearly along with the increasing of air flow and water spray density. But there are a best air flow value of 2.98 m/s and a best spray water density of 0.064 kg/(m ·s) respectively, if continue to increase them, condensation performance is not significantly improved any more. The test results are available to improve the evaporative condenser performance and the designing lever. 展开更多
关键词 thermal transfer resistance horizontal tube heat exchanger evaporative condenser
下载PDF
New experimental method for inundation effect of film condensation on horizontal tube bundle 被引量:3
3
作者 MA ZhiXian ZHANG JiLi SUN DeXing 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第10期2856-2863,共8页
Theory of film condensation heat transfer(FCHT) for vapor condensed on horizontal tube bundle(HTB) is vital to many industry processes.Meanwhile,the inundation effect is the key to model the film condensation heat tra... Theory of film condensation heat transfer(FCHT) for vapor condensed on horizontal tube bundle(HTB) is vital to many industry processes.Meanwhile,the inundation effect is the key to model the film condensation heat transfer coefficient(CHTC) on HTB.This paper proposed a new experimental method,homologous method,to obtain the inundation effect precisely.Based on the requirements of the new test method,a new test facility was designed and established.Then,the superiority of homologous method for inundation effect was investigated based on experiment result and theoretic analysis.The results showed that the homogenous method can effectively control the experimental error of inundation effect,which is less than 50% of the error of CHTC,and less than 30% of the error of the inundation effect gained by routine method.The new test facility built for the homogenous method is excellent in obtaining the accurate inundation effect of film condensation on HTB.All the result is a foundation of the theoretical development of the FCHT on HTB. 展开更多
关键词 horizontal tube bundle film condensation inundation effect experimental method experimental error
原文传递
Experimental Study of Falling-film Mode Transitions between Horizontal Tubes in CaCl_2/Water Absorber
4
作者 XU Zhen SUN Wenqian +2 位作者 LU Yuan XIAO Yunhan XIE Yingchun 《Journal of Thermal Science》 SCIE EI CAS CSCD 2014年第4期338-345,共8页
It is important to accurately predict the flow mode especially intertube falling-film mode of absorbent for its great impact on the heat and mass transfer in a horizontal tube absorber. In this paper, a test facility ... It is important to accurately predict the flow mode especially intertube falling-film mode of absorbent for its great impact on the heat and mass transfer in a horizontal tube absorber. In this paper, a test facility used to study falling-film outside horizontal tubes was built, and experiments were conducted to explore the intertube mode transi- tions with water-calcium chloride (CaC12/water) solution in quiescent surroundings. The correlations which are more suitable for predicting CaC1jwater solution intertube mode transitions were developed. In general, the transitional Re will decrease with the solution concentration increasing, and its effects increase with the transitions from droplet mode to sheet mode. Hysteresis exists in all the mode transitions, and it is more obvious for low concentration solutions. The results may be an important support for modeling, designing and operating of CaC12/water falling-film absorber. 展开更多
关键词 horizontal tube mode transitions water-calcium chloride solution CORRELATIONS
原文传递
Heat Transfer in Horizontal Copper Tube Heated by Electric Heating Process
5
作者 Ramesh Chandra Nayak Abinash Sahoo +1 位作者 Manmatha KRoul Saroj kuSarangi 《Electrical Science & Engineering》 2020年第2期1-4,共4页
Heat transfer from electrical and electronics component is essential for better performance of that electrical system,The maximum heat transfer from that system results long period durability.In most of the system bas... Heat transfer from electrical and electronics component is essential for better performance of that electrical system,The maximum heat transfer from that system results long period durability.In most of the system base provided for equipments are very small and placed in a very complicated position.so heat transfer by forced convection is not easy for that purpose.The heat transfer by natural convection is the familiar technique used in electronics cooling;there is huge group of apparatus that lends itself to natural convection.This category consist of stand-alone correspondence such as modems and small computers having an array of printed circuit boards(PCB)accumulate within an area.Natural convection heat transfer in heated horizontal duct drive away heat from the interior surface is offered.The duct is open-ended and round in cross section.The test section is heated by provision of heating coils,where constant wall heat flux mentioned.Heat transfer experiment is carried out for channel of 50 mm.internal diameter and 4 mm thickness with length 600 mm.Ratios of length to diameter of the channel are taken as L/D=12.Wall heat fluxes maintained at q//=300 W/m2 to 3150 W/m2.A methodical investigational record for the local steady state natural convection heat transfer activities is obtained.The wall heating condition on local steady-state heat transfer phenomena are studied.The present experimental data is compared with the existing theoretical and experimental results for the cases of vertical smooth tubes. 展开更多
关键词 Heat transfer COMPONENTS SYSTEM horizontal tube Heating coil Heat flux Smooth tubes Test section
下载PDF
Numerical Study on Flow Heat Transfer Characteristics of Horizontal Tube Falling-Film Evaporator 被引量:2
6
作者 XU Bo JIANG Chun CHEN Zhenqian 《Journal of Thermal Science》 SCIE EI CAS CSCD 2021年第4期1302-1317,共16页
As an efficient and energy-saving heat exchange technology, horizontal tube falling film evaporation has a great application prospect in refrigeration and air conditioning. The three-dimensional models of falling film... As an efficient and energy-saving heat exchange technology, horizontal tube falling film evaporation has a great application prospect in refrigeration and air conditioning. The three-dimensional models of falling film flow evaporation outside horizontal single tube and inside evaporator were established, and the accuracy of flow and heat transfer simulation process was verified by comparison. For horizontal single tube, the results showed that total heat transfer coefficient was low and increased with larger spray density and evaporation temperature. The thickness of liquid film outside tube decreased gradually with the increase of tube diameter, and the total heat transfer coefficient of small tube diameter was significantly greater than that of the large tube diameter. The total heat transfer coefficient presented an increasing trend with larger liquid distribution height and density. In addition, the fluctuation of tube axial liquid film thickness distribution decreased with larger liquid distribution density. For evaporator, the results indicated that part of liquid refrigerant was carried into the vapor outlet. The temperature of tube wall and fluid presented a gradually rising trend in vertical downward direction, while tube wall temperature within the same horizontal and transverse row had little difference. The high-temperature zone on the outer wall of heat exchange tube moved towards the inlet and gradually decreased, and the outlet temperature of water in the tube also gradually decreased with the increase of refrigerant spray density. The local heat transfer coefficient of heat exchanger tube in the vertical direction presented a downward trend which was more obvious with the smaller spray density and it was obviously higher located in the middle of upper tube row and both sides of lower tube row for horizontal tube rows. 展开更多
关键词 horizontal single tube EVAPORATOR falling film numerical simulation heat transfer
原文传递
Numerical Study on Heat Transfer Enhancement for Use of Corrugated, Nodal and Horizontal Grain Tubes 被引量:1
7
作者 朱家玲 王钰沛 +1 位作者 张伟 刘雪玲 《Transactions of Tianjin University》 EI CAS 2014年第5期385-392,共8页
With isopentane as working fluid, the heat transfer performances for corrugated, nodal and horizontal grain tubes are simulated. The structural parameters of the three kinds of tubes are compared with those of the pla... With isopentane as working fluid, the heat transfer performances for corrugated, nodal and horizontal grain tubes are simulated. The structural parameters of the three kinds of tubes are compared with those of the plain tube. The numerical results using computational fluid dynamics are validated with theoretical values. For the corrugated, nodal and horizontal grain tubes, the heat transfer enhancements(HTEs) are 2.31—2.53, 1.18—1.86 and 1.02—1.31 times of those of the plain tube, respectively. However, the improved HTEs are at the expense of pressure losses. The drag coefficients are 6.10—7.09, 2.06—11.03 and 0.53—1.83 higher, respectively. From the viewpoint of comprehensive heat transfer factor, the corrugated tube is recommended for engineering applications, followed by the horizontal grain tube. 展开更多
关键词 corrugated tube nodal tube horizontal grain tube heat transfer
下载PDF
Experimental study on pressure fluctuation characteristics of slug flow in horizontal curved tubes 被引量:1
8
作者 邓志安 Xiao Xue 《High Technology Letters》 EI CAS 2017年第1期23-29,共7页
In order to study the pressure characteristics of slug flow in horizontal curved tubes,two kinds of curved tubes with central angle 45° and 90° respectively are studied,of which are with 0. 5m circumference ... In order to study the pressure characteristics of slug flow in horizontal curved tubes,two kinds of curved tubes with central angle 45° and 90° respectively are studied,of which are with 0. 5m circumference and 26 mm inner diameter are used. When the superficial liquid velocity or the superficial gas velocity is constant,the pressure fluctuations and the probability distribution of the average velocity of slug flow are clear for all of the five experimental conditions. The results of experiment show that the pressure characteristics of slug flow in curved tubes have periodic fluctuations. With the rise of central angle,the period of pressure fluctuation is more obvious. The system pressure of the slug flow increases with the increasing of superficial liquid/gas velocity. Meanwhile,the probability distribution of pressure signal shows regularity,such as unimodal,bimodal or multimodal. 展开更多
关键词 slug flow horizontal curved tube pressure fluctuations central angle
下载PDF
Convective Boiling of Near-Azeotropic Refrigerant R410A in the Horizontal Micro-fin Tube
9
作者 段雪涛 马虎根 +1 位作者 邬志敏 王芳 《Journal of Shanghai Jiaotong university(Science)》 EI 2007年第1期73-75,80,共4页
Using near-azeotropic refrigerant R410A as the working fluid, the experimental studies on the horizontal micro-fin tubes were conducted. Several factors affecting heat transfer coefficients were analyzed, and the char... Using near-azeotropic refrigerant R410A as the working fluid, the experimental studies on the horizontal micro-fin tubes were conducted. Several factors affecting heat transfer coefficients were analyzed, and the characteristics of flow boiling of the refrigerant in the horizontal micro-fin tubes were discussed. The local heat transfer coefficients increase with mass flux, heat flux and quality. And the heat transfer enhancement factor of those testing tubes is about 1.6 to 2.2. 展开更多
关键词 horizontal micro-fin tube near-azeotropic refrigerant convective evaporation heat transfer
下载PDF
CuO–TiO_(2) based self-powered broad band photodetector
10
作者 Chiranjib Ghosh Arka Dey +7 位作者 Iman Biswas Rajeev Kumar Gupta Vikram Singh Yadav Ashish Yadav Neha Yadav Hongyu Zheng Mohamed Henini Aniruddha Mondal 《Nano Materials Science》 EI CAS CSCD 2024年第3期345-354,共10页
An efficient room-temperature self-powered,broadband(300 nm–1100 nm)photodetector based on a CuO–TiO_(2)/TiO_(2)/p-Si(100)heterostructure is demonstrated.The CuO–TiO_(2)nanocomposites were grown in a two-zone horiz... An efficient room-temperature self-powered,broadband(300 nm–1100 nm)photodetector based on a CuO–TiO_(2)/TiO_(2)/p-Si(100)heterostructure is demonstrated.The CuO–TiO_(2)nanocomposites were grown in a two-zone horizontal tube furnace on a 40 nm TiO_(2)thin film deposited on a p-type Si(100)substrate.The CuO–TiO_(2)/TiO_(2)/p-Si(100)devices exhibited excellent rectification characteristics under dark and individual photoillumination conditions.The devices showed remarkable photo-response under broadband(300–1100 nm)light illumination at zero bias voltage,indicating the achievement of highly sensitive self-powered photodetectors at visible and near-infrared light illuminations.The maximum response of the devices is observed at 300 nm for an illumination power of 10 W.The response and recovery times were calculated as 86 ms and 78 ms,respectively.Moreover,under a small bias,the devices showed a prompt binary response by altering the current from positive to negative under illumination conditions.The main reason behind this binary response is the low turn-on voltage and photovoltaic characteristics of the devices.Under illumination conditions,the generation of photocurrent is due to the separation of photogenerated electron-hole pairs within the built-in electric field at the CuO–TiO_(2)/TiO_(2)interface.These characteristics make the CuO–TiO_(2)/TiO_(2)broadband photodetectors suitable for applications that require high response speeds and self-sufficient functionality. 展开更多
关键词 SELF-POWERED CuO–TiO_(2) nanocomposite Broadband photodetector Two-zone horizontal tube furnace RESPONSIVITY
下载PDF
Numerical simulation of liquid falling film on horizontal circular tubes 被引量:7
11
作者 Fengdan SUN Songlin XU Yongchuan GAO 《Frontiers of Chemical Science and Engineering》 CAS CSCD 2012年第3期322-328,共7页
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 ... 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. 展开更多
关键词 falling film horizontal tube flow characteristics film thickness liquid feeder height
原文传递
Numerical simulation on flow of ice slurry in horizontal straight tube
12
作者 Shengchun LIU Ming SONG +1 位作者 Ling HAO Pengxiao WANG 《Frontiers in Energy》 SCIE CSCD 2021年第1期201-207,共7页
Numerical simulation on flow of ice slurry in horizontal straight tubes was conducted in this paper to improve its transportation characteristics and application.This paper determined the influence of the diameter and... Numerical simulation on flow of ice slurry in horizontal straight tubes was conducted in this paper to improve its transportation characteristics and application.This paper determined the influence of the diameter and length of tubes,the ice packing factors(IPF)and the flow velocity of ice slurry on pressure loss by using numerical simulation,based on two-phase flow and the granular dynamic theory.Furthermore,it was found that the deviation between the simulation results and experimental data could be reduced from 20%to 5%by adjusting the viscosity which was reflected by velocity.This confirmed the reliability of the simulation model.Thus,two mathematical correlations between viscosity and flow velocity were developed eventually.It could also be concluded that future rheological model of ice slurry should be considered in three sections clarified by the flow velocity,which determined the fundamental difference from single-phase fluid. 展开更多
关键词 ice slurry horizontal tubes numerical simulation pressure drop viscosity model
原文传递
Experimental Investigation of Forced Convective Boiling Flow Instabilities in Horizontal Helically Coiled Tubes 被引量:7
13
作者 L. J. Guo Z. P. Feng +1 位作者 X. J. Chen N. H. Thomas 《Journal of Thermal Science》 SCIE EI CAS CSCD 1996年第3期210-216,共7页
An experimental investigation is described for the characteristics of convective boiling flow instabilities in horizontally helically coiled tubes using a steam-water two-phase closed circulation test loop at pressure... An experimental investigation is described for the characteristics of convective boiling flow instabilities in horizontally helically coiled tubes using a steam-water two-phase closed circulation test loop at pressure from 0.5 MPa to 3.5 MPa. Three kinds of oscillation are reported: density waves; pressure drop excursions; thermal fluctuations. We describe their dependence on main system parameters such as system pressure, mass flowrate, inlet subcooling, compressible volume and heat flux. Utilizing the experimental data together with conservation constraints, a dimensionless correlation is proposed for the occurrence of density waves. 展开更多
关键词 two-phase flow forced convective boiling flow instabilities horizontal helically coiled tubes experimental investigation
原文传递
A study of spray granulation in vibrated fluidized bed with internal heating tubes
14
作者 Xiaoheng PAN Shichao YE +2 位作者 Zeguang ZHANG Li ZHANG Xuejun ZHU 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2009年第1期78-82,共5页
The granulation process in a vibratedfluidized bed with immersed horizontal heating tubes was studied in this paper,with small monoammonium phosphate particles as the initial particles and monoammonium phosphate soluti... The granulation process in a vibratedfluidized bed with immersed horizontal heating tubes was studied in this paper,with small monoammonium phosphate particles as the initial particles and monoammonium phosphate solution sprayed on them.The concrete influences on the granulating performance of the immersed horizontal heating power,fluidizing gas velocity,vibration frequency and amplitude had been analyzed theoretically.The results show that appropriate vibration intensity is a preferred condition for the growth of partials,but thefine dust will become much more along with prolonged vibration.Increasing the heating power is beneficial to raise the growth rate.Particles will grow faster if thefluidizing gas velocity is higher,but this will cause morefine dust.The optimized condition of A=0.002 m,f=6.67 Hz,u=1.4 m/s was given after the analysis of the experimental results.In the end,a semiempirical formula was derived from the experiment data,and the calculation results show good agreement with the experimental data. 展开更多
关键词 vibratedfluidized bed immersed horizontal horizontal heating tubes spray granulation particle growth model
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部