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Investigations on High-Speed Flash Boiling Atomization of Fuel Based on Numerical Simulations
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作者 Wei Zhong Zhenfang Xin +1 位作者 Lihua Wang Haiping Liu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第5期1427-1453,共27页
Flash boiling atomization(FBA)is a promising approach for enhancing spray atomization,which can generate a fine and more evenly distributed spray by increasing the fuel injection temperature or reducing the ambient pr... Flash boiling atomization(FBA)is a promising approach for enhancing spray atomization,which can generate a fine and more evenly distributed spray by increasing the fuel injection temperature or reducing the ambient pressure.However,when the outlet speed of the nozzle exceeds 400 m/s,investigating high-speed flash boiling atomization(HFBA)becomes quite challenging.This difficulty arises fromthe involvement ofmany complex physical processes and the requirement for a very fine mesh in numerical simulations.In this study,an HFBA model for gasoline direct injection(GDI)is established.This model incorporates primary and secondary atomization,as well as vaporization and boilingmodels,to describe the development process of the flash boiling spray.Compared to lowspeed FBA,these physical processes significantly impact HFBA.In this model,the Eulerian description is utilized for modeling the gas,and the Lagrangian description is applied to model the droplets,which effectively captures the movement of the droplets and avoids excessive mesh in the Eulerian coordinates.Under various conditions,numerical solutions of the Sauter mean diameter(SMD)for GDI show good agreement with experimental data,validating the proposed model’s performance.Simulations based on this HFBA model investigate the influences of fuel injection temperature and ambient pressure on the atomization process.Numerical analyses of the velocity field,temperature field,vapor mass fraction distribution,particle size distribution,and spray penetration length under different superheat degrees reveal that high injection temperature or low ambient pressure significantly affects the formation of small and dispersed droplet distribution.This effect is conducive to the refinement of spray particles and enhances atomization. 展开更多
关键词 High-speed flash boiling atomization numerical simulations Eulerian description Lagrangian description gasoline direct injection
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Experimental Study on the Bubble Dynamics of Magnetized Water Boiling
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作者 Yang Cao Jianshu Liu Xuhui Meng 《Frontiers in Heat and Mass Transfer》 EI 2024年第2期675-685,共11页
Boiling heat transfer,as an efficient heat transfer approach,that can absorb a large amount of latent heat during the vaporization,is especially suitable for heat transfer occasions with high heat flux demands.Experim... Boiling heat transfer,as an efficient heat transfer approach,that can absorb a large amount of latent heat during the vaporization,is especially suitable for heat transfer occasions with high heat flux demands.Experimental studies show that the surface tension coefficient of pure water can be reduced sharply(up to 25%)when it is magnetized by amagnetic field applied externally.In this paper,magnetized water(MW)was used as the work fluid to conduct boiling heat transfer experiments,to explore the influence of magnetization on the boiling characteristics of pure water.The electromagnetic device was used to magnetize water,and then the MW was used as the work-fluid of boiling heat transfer experiments,the bubble dynamic behavior of the MW boiling was captured by a video camera,and the characteristics andmechanism were analyzed.It was found that at the same conditions,the boiling of MW can produce more vapor bubbles of smaller size than the water without magnetization,which leads to a higher heat-transfer efficiency.This indicates that magnetization can enhance the boiling heat transfer of pure water.Furthermore,the thermal conditions required by magnetized water when the boiling is started are lower than the non-magnetized water boiling,whichmeans the earlier start of nucleate pool boiling when using the MW. 展开更多
关键词 boiling heat transfer MAGNETIZATION surface tension
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A Novel Numerical Method for Simulating Boiling Heat Transfer of Nanofluids
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作者 Yang Cao Xuhui Meng 《Frontiers in Heat and Mass Transfer》 EI 2024年第2期583-595,共13页
In this paper,a new approach called the Eulerian species method was proposed for simulating the convective and/or boiling heat transfer of nanofluids.The movement of nanoparticles in nanofluids is tracked by the speci... In this paper,a new approach called the Eulerian species method was proposed for simulating the convective and/or boiling heat transfer of nanofluids.The movement of nanoparticles in nanofluids is tracked by the species transport equation,and the boiling process of nanofluids is computed by the Eulerian multiphase method coupled with the RPI boiling model.The validity of the species transport equation for simulating nanoparticles movement was verified by conducting a simulation of nanofluids convective heat transfer.Simulation results of boiling heat transfer of nanofluids were obtained by using the commercial CFD software ANSYS Fluent and compared with experimental data and results from another numerical method(Eulerian three-phase model).Good agreement with experimental data was achieved,and it was proved the Eulerian species method is better than the Eulerian three-phase model since it can give better simulation results with higher accuracy but needs fewer computation resources. 展开更多
关键词 Nanofluids simulations boiling heat transfer species transport
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Effect of the Geometrical Parameter of OpenMicrochannel on Pool Boiling Enhancement
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作者 Ali M.H.Al-Obaidy Ekhlas M.Fayyadh Amer M.Al-Dabagh 《Frontiers in Heat and Mass Transfer》 EI 2024年第5期1421-1442,共22页
High heat dissipation is required for miniaturization and increasing the power of electronic systems.Pool boiling is a promising option for achieving efficient heat dissipation at low wall superheat without the need f... High heat dissipation is required for miniaturization and increasing the power of electronic systems.Pool boiling is a promising option for achieving efficient heat dissipation at low wall superheat without the need for moving parts.Many studies have focused on improving heat transfer efficiency during boiling by modifying the surface of the heating element.This paper presents an experimental investigation on improving pool boiling heat transfer using an open microchannel.The primary goal of this work is to investigate the impact of the channel geometry characteristics on boiling heat transfer.Initially,rectangular microchannels were prepared on a circular copper test piece with a diameter of 20 mm.Then,the boiling characteristics of these microchannels were compared with those of a smooth surface under saturated conditions using deionized water.In this investigation,a wire-cutting electrical discharge machine(EDM)machine was used to produce parallel microchannels with channel widths of 0.2,0.4,and 0.8 mm.The fin thicknesses were 0.2,0.4,and 0.6 mm,while the channel depth remained constant at 0.4 mm.The results manifested that the surface featuring narrower fins and broader channels achieved superior performance.The heat transfer coefficient(HTC)was enhanced by a maximum of 248%,and the critical heat flux(CHF)was enhanced by a maximum of 101%compared to a plain surface.Eventually,the obtained results were compared with previous research and elucidated a good agreement. 展开更多
关键词 Pool boiling microchannel surface geometrical parameter heat transfer enhancement critical heat flux
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Effect of Gd on neutron absorption properties and electrochemical corrosion behavior of Zr-Gd alloy in boiling concentrated HNO3 被引量:2
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作者 Cheng-Jie Du Xiao-Gang Hu +2 位作者 Ping-Yi Guo Xiao-Long Pan Jin-Ping Wu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第3期40-51,共12页
A Zr-Gd alloy with neutron poisoning properties and resistance to boiling concentrated HNO3 corrosion was developed based on a corrosion-resistant Zr-702 alloy to meet the demand for neutron shielding in the closed-lo... A Zr-Gd alloy with neutron poisoning properties and resistance to boiling concentrated HNO3 corrosion was developed based on a corrosion-resistant Zr-702 alloy to meet the demand for neutron shielding in the closed-loop treatment of spent fuel and the nuclear chemical industry.In this study,1 wt.%,3 wt.%,5 wt.%,7 wt.%,and 9 wt.%Zr-Gd alloys were designed and fabricated with Zr-702 as the control element.The electrochemical behavior of the Zr-Gd alloys in boiling concentrated HNO3 was investigated,and the neutron shielding effect on plate thickness and Gd content was simulated.The experimental results demonstrate that the corrosion resistance of the alloy decreased slightly before~7-9 wt.%with increasing Gd content;this is the inflection point of its corrosion resistance.The alloy uniformly dissolved the Gd content that could not be dissolved in the Zr lattice,resulting in numerous micropores on the passivation coating,which deteriorated and accelerated the corrosion rate.The MCNP simulation demonstrated that when the Gd content was increased to 5 wt.%,a 2-mm-thick plate can shield 99.9%neutrons;an alloy with a Gd content≥7 wt.%required only a 1-mm-thick plate,thereby showing that the addition of Gd provides an excellent neutron poisoning effect.Thus,the corrosion resistance and neutron shielding performance of the Zr-Gd alloy can meet the harsh service requirements of the nuclear industry. 展开更多
关键词 Zr-Gd alloy boiling concentrated HNO3 Electrochemistry Neutron shielding MCNP
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Simulation of single bubble dynamic process in pool boiling process under microgravity based on phase field method
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作者 朱昶胜 赵博睿 +1 位作者 雷瑶 郭秀婷 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第4期473-481,共9页
We use the phase field method to track the gas-liquid interface based on the gas-liquid two-phase flow in the pool boiling process,and study the bubble nucleation,growth,deformation,departure and other dynamic behavio... We use the phase field method to track the gas-liquid interface based on the gas-liquid two-phase flow in the pool boiling process,and study the bubble nucleation,growth,deformation,departure and other dynamic behaviors on the heating surface under microgravity.By simulating the correlation between liquid undercooling and bubble dynamics,we find that the bubble growth time increases with the increase of liquid undercooling,but the effect of liquid undercooling on bubble height is not significant.Meanwhile,the gas-liquid-solid three-phase contact angle and the gravity level will also have an effect on the bubble growth time and bubble height.With the increase of the contact angle,the bubble growth time and bubble height when the bubble departs also increase.While the effect of gravity level is on the contrary,the smaller the gravity level is,the larger the bubble height and bubble growth time when the bubble separates. 展开更多
关键词 pool boiling single-bubble phase-field method low-gravity
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Comparisons of Structured Surface Floors for Pool Boiling Enhancement at Low Heat Fluxes: Hands-On Learning Setup for Heat Transfer Classroom
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作者 Birce Dikici Basim Q. A. Al-Sukaini 《World Journal of Engineering and Technology》 2023年第2期303-318,共16页
Various enhanced surfaces have been proposed over the years to improve boiling heat transfer. This paper introduces an experimental setup designed for boiling demonstration in the graduate-level Heat Transfer course. ... Various enhanced surfaces have been proposed over the years to improve boiling heat transfer. This paper introduces an experimental setup designed for boiling demonstration in the graduate-level Heat Transfer course. The pool boiling performance of water under atmospheric pressure of 1.025 bar is investigated by using several structured surfaces at heat fluxes of 28 and 35 kW/m<sup>2</sup>. Surfaces with holes, rectangular grooves, and mushroom fins are manufactured by an NC-controlled vertical milling machine. The heat flux versus excess temperature graph is plotted by using thermocouple measurements of water and base temperatures of the boiling vessel. The separation, rise, and growth of individual vapor bubbles from the surface during boiling were recorded with a digital camera. The results for the plain surface are compared to the Rohsenow correlation. The enhancement of heat transfer coefficient (h) ranged between 15% - 44.5% for all structured surfaces. The highest heat transfer coefficient enhancement is observed between 41% - 56.5% for holed surface-3 (405 holes) compared to the plain surface. The excess temperature dropped around 29% - 34% for holed surface-3 (405 holes) compared to the plain surface. The heat transfer coefficient increases as the spacing between channels or holes decreases. While the bubbles on holed and mushroomed surfaces were spherical, the bubbles on the flat and grooved surfaces were observed as formless. The suggested economical test design could be appropriate to keep students focused and participating in the classroom. 展开更多
关键词 boiling Pool boiling Heat Transfer Coefficient Enhancement Techniques Engineering Education
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Experimental and Numerical Analysis of the Influence ofMicrochannel Size and Structure on Boiling Heat Transfer
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作者 Ningbo Guo Xianming Gao +3 位作者 Duanling Li Jixing Zhang Penghui Yin Mengyi Hua 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第9期3061-3082,共22页
Computational fluid dynamics was used and a numerical simulation analysis of boiling heat transfer in microchannels with three depths and three cross-sectional profiles was conducted.The heat transfer coefficient and ... Computational fluid dynamics was used and a numerical simulation analysis of boiling heat transfer in microchannels with three depths and three cross-sectional profiles was conducted.The heat transfer coefficient and bubble generation process of three microchannel structures with a width of 80μm and a depth of 40,60,and 80μm were compared during the boiling process,and the factors influencing bubble generation were studied.A visual test bench was built,and test substrates of different sizes were prepared using a micro-nano laser.During the test,the behavior characteristics of the bubbles on the boiling surface and the temperature change of the heated wall were collected with a high-speed camera and a temperature sensor.It was found that the microchannel with a depth of 80μm had the largest heat transfer coefficient and shortest bubble growth period,the rectangular channel had a larger peak heat transfer coefficient and a lower frequency of bubble occurrence,while the V-shaped channel had the shortest growth period,i.e.,the highest frequency of bubble occurrence,but its heat transfer coefficient was smaller than that of the rectangular channel. 展开更多
关键词 MICROCHANNEL boiling heat transfer BUBBLE numerical simulation visual experiment
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Lattice Boltzmann simulation of the effects of cavity structures and heater thermal conductivity on nucleate boiling heat transfer
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作者 Fanming CAI Zhaomiao LIU +2 位作者 Nan ZHENG Yanlin REN Yan PANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第6期981-996,共16页
The boiling heat transfer technology with cavity surfaces can provide higher heat flux under lower wall superheat,which is of great significance for the cooling of electronic chips and microelectromechanical devices.I... The boiling heat transfer technology with cavity surfaces can provide higher heat flux under lower wall superheat,which is of great significance for the cooling of electronic chips and microelectromechanical devices.In this paper,the boiling characteristics of the cavity surfaces are investigated based on the lattice Boltzmann(LB)method,focusing on the effects of cavity shapes,sizes,and heater thermal conductivity on the heat transfer performance.The results show that the triangular cavity has the best boiling performance since it has less residual vapor and higher bubble departure frequency than those of the trapezoidal and rectangular cavities.As the cavity size increases,the enhancement of heat transfer by the cavity mouth is suppressed by the heat accumulation effect at the heater bottom.The liquid rewetting process during bubble departure is the reason for the fluctuation of the space-averaged heat flux,and the heater thermal conductivity determines the fluctuation amplitude.The evaporation of liquid in the cavity with high thermal conductivity walls is more intense,resulting in shorter waiting time and higher bubble departure frequency. 展开更多
关键词 lattice Boltzmann(LB)method boiling CAVITY conjugate heat transfer
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The‘New Normal’of Extreme Weather And the Urgency of Transformation“The era of global warming is over and the era of global boiling has arrived.”
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作者 By YuanYanem Zhu Mengxiao 《China Report ASEAN》 2023年第8期22-25,共4页
Phong,a 42-year-old Vietnamese motorcyclist begins his busy day at 5 a.m.In Hanoi,light motorcycles are an important mode of transportation.Countless motorcycles shuttle through the streets and alleys of the city,tran... Phong,a 42-year-old Vietnamese motorcyclist begins his busy day at 5 a.m.In Hanoi,light motorcycles are an important mode of transportation.Countless motorcycles shuttle through the streets and alleys of the city,transporting parcels,goods,and passengers to various destinations.Phong usually works for 12 hours straight with little rest.However,the unprecedented heat waves this summer had often pushed daytime temperatures to above 40 degrees Celsius,making it extremely difficult for Phong to complete his daily routine.Phong prepared a hat,a wet handkerchief,and more drinking water.He even installed a small umbrella above his mobile phone rack to prevent the phone from overheating in the sun because it is his only source of work.Despite all the equipment,he is still worried.“If I suffer heat stroke or anything else,I will be unable to work,”he said.“I can’t afford it.” 展开更多
关键词 Transformation boiling STRAIGHT
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A new heat transfer correlation for flow boiling in helically coiled tubes 被引量:1
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作者 冀翠莲 韩吉田 +2 位作者 刘晓鹏 邵莉 陈常念 《Journal of Southeast University(English Edition)》 EI CAS 2015年第3期380-383,共4页
Based on the superposition principle of the nucleate boiling and convective heat transfer terms,a new correlation is developed for flow boiling heat transfer characteristics in helically coiled tubes.The effects of th... Based on the superposition principle of the nucleate boiling and convective heat transfer terms,a new correlation is developed for flow boiling heat transfer characteristics in helically coiled tubes.The effects of the geometric and system parameters on heat transfer characteristics in helically coiled tubes are investigated by collecting large amounts of experimental data and analyzing the heat transfer mechanisms. The existing correlations are divided into two categories,and they are calculated with the experimental data.The Dn factor is introduced to take into account the effect of a complex geometrical structure on flow boiling heat transfer.A new correlation is developed for predicting the flow boiling heat transfer coefficients in the helically coiled tubes,which is validated by the experimental data of R134a flow boiling heat transfer in them;and the average relative error and root mean square error of the new correlation are calculated.The results show that the new correlation agrees well with the experimental data,indicating that the new correlation can be used for predicting flow boiling heat transfer characteristics in the helically coiled tubes. 展开更多
关键词 helically coiled tube flow boiling heat transfer coefficient correlation heat transfer
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Pool boiling performance of porous surface tubes under vacuum conditions 被引量:1
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作者 王学生 代晶晶 +1 位作者 从建立 陈琴珠 《Journal of Southeast University(English Edition)》 EI CAS 2010年第2期339-342,共4页
Two types of tube bundles are designed,which are,respectively,composed of six tubes arranged in the boiling chamber.The nucleate pool boiling performance of smooth tube bundles and sintered porous surface tube bundles... Two types of tube bundles are designed,which are,respectively,composed of six tubes arranged in the boiling chamber.The nucleate pool boiling performance of smooth tube bundles and sintered porous surface tube bundles with deionized water as a medium are experimentally studied at atmospheric and sub-atmospheric pressures,respectively.The experimental results indicate that the boiling heat transfer coefficients of the two types of tube bundles increase with the increase in pressure under vacuum conditions as they behave under ordinary pressure.As the pressure varies from 10 to 100 kPa,it also can be seen that the heat transfer coefficient of the sintered porous surface tube is increased by 0.2 to 4 times compared with the smooth one under the same operating parameters.In addition,the experimental data show that a definite bundle effect exists in both sintered porous surface tubes and smooth tubes under vacuum conditions. 展开更多
关键词 pool boiling porous surface tube heat transfer enhancement
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Preparation and characteristic analysis of rice husk high boiling solvent lignin 被引量:2
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作者 陈云平 程贤甦 《Journal of Forestry Research》 SCIE CAS CSCD 2008年第2期159-163,共5页
Rice husk high boiling solvent lignin (RHL) was prepared by high boiling solvent method, and its characteristics was analyzed by using chemical composition analysis, infrared spectroscopy, and ^1H-NMR and ^13C-NMR s... Rice husk high boiling solvent lignin (RHL) was prepared by high boiling solvent method, and its characteristics was analyzed by using chemical composition analysis, infrared spectroscopy, and ^1H-NMR and ^13C-NMR spectroscopy. The optimum prepared condition was that the rice husk with 70%-90% aqueous solution of 1, 4-butanediol was mixed with autoclave, under a certain weight ratio of solid raw material and solvent, heated to 200-220℃ for 1.0-3.0 h, then water-insoluble RHL was separated from the liquor reaction mixture by water precipitation. Results suggested that the lower digestion temperature and concentration of 1,4-butanediol were both unfavorable for extracting lignin. Chemical weight-average molecular weight of RHL was 1939 g·mol^-1, and the residual polysaccharide content was 5.12%. The ^1H-NMR spectra of RHL showed the relative intensity ratio, aliphatic over aromatic methoxyl groups, situated at 3.5-3.8 and 3.8-4.0 ppm, respectively. The results from ^13C-NMR spectra showed that β-O-4 bond and β-5 carbon-carbon linkage were the major linkages between RHL units. The C9-formula of RHL was calculated by the experiment data. 展开更多
关键词 high boiling solvent method rice husk lignin C9-formula
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Forced Convection Boiling Heat Transfer and Dryout Characteristics in Helical Coiled Tubes with Various Axial Angles 被引量:4
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作者 郭烈锦 张西民 +1 位作者 冯自平 陈学俊 《应用基础与工程科学学报》 EI CSCD 1998年第4期61-69,共9页
对水和水蒸汽汽液两相流体在螺旋轴呈各种倾角放置的螺旋管内强制对流沸腾传热与烧毁特性进行了系统地试验研究,试验中系统及结构参数范围如下:压力:P=0.4~3.0MPa质量流速:G=100~2400kg/m2·s进口... 对水和水蒸汽汽液两相流体在螺旋轴呈各种倾角放置的螺旋管内强制对流沸腾传热与烧毁特性进行了系统地试验研究,试验中系统及结构参数范围如下:压力:P=0.4~3.0MPa质量流速:G=100~2400kg/m2·s进口水温:T=30~80℃出口干度:x=-0.05~1.2管内壁面热负荷:q=0~540kE/m2试验段结构参数:总长L=6448mm,管内径d=11mm,螺旋直径D=256mm,螺旋升角β=4.27°螺旋管轴向放置倾角:水平位置(0°)、向上倾斜45°(+45°)、垂直向上(+90°)、向下倾斜45°(-45°).共进行了1050个工况的试验.试验结果表明,螺旋管内汽液两相流强制对流沸腾传热可以划分为核态沸腾区、两相流强制对流区、烧毁及烧毁后传热区等3种区域.通过数据处理和分析总结,给出了3区域间转变的边界方程,和3个区域内两相流传热系数的计算公式.根据试验观察和数据结果,对烧毁现象及烧毁点或区域发生的条件及机理进行了深入的分析研究,发现一系列有关现象的规律和特点,指出了其主要影响因素,并给出了烧毁点临界质量干度的预报公式. 展开更多
关键词 螺旋管 水/水蒸汽汽液两相流 强制对流沸腾传热 烧毁
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Changes of Petroleum Acid Distribution Characterized by FT-ICR MS in Heavy Acidic Crude Oil after True Boiling Point Distillation 被引量:8
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作者 Liu Yingrong Zhang Qundan +3 位作者 Wang Wei Liu Zelong Zhu Xinyi Tian Songbai 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2014年第1期8-12,共5页
The molecular transformations of carboxylic acids in heavy acidic SL crude before and after true boiling point distillation were examined by ultra-high resolution negative-ion electrospray ionization(ESI) Fourier tran... The molecular transformations of carboxylic acids in heavy acidic SL crude before and after true boiling point distillation were examined by ultra-high resolution negative-ion electrospray ionization(ESI) Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS). The acid class(heteroatom number), type(z numbers) and carbon number distributions were positively characterized. It was found out that the total acid number(TAN) of SL crude decreased after true boiling point distillation, and the abundance of O2 class in mass spectra was also found to be reduced from 67.6% to 34.5% in SL TBP mixed crude as measured by MS spectra, indicating to a potential carboxylic acid decomposition. However, it was interesting that the carboxylic acids type distribution in both oils was almost the same although their relative abundance in SL TBP mixed crude turned to be much lower, suggesting that various petroleum carboxylic acid types have the similar thermal decomposition reaction behavior. Furthermore, for each O2 type of acids in SL TBP mixed crude, the abundance of carboxylic acids with carbon number higher than 35 was reduced greatly, especially for those with carbon number higher than 60, the mass peaks of which were nearly totally removed, indicating that the large carboxylic acid molecules in heavy fractions decomposed more significantly because of longer heating time during the true boiling point distillation process. As a result, the reduction of TAN may be caused by the thermal decomposition of carboxylic acids especially those with high carbon number, suggesting that quick distillation or much lower pressure is required to avoid the thermal decomposition. 展开更多
关键词 true boiling point distillation carboxylic acid ESI FT-ICR MS acidic crude total acid number(TAN)
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FLOW BOILING HEAT TRANSFER WITH FLUIDIZED SOLID PARTICLES 被引量:1
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作者 李修伦 闻建平 谷俊杰 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 1995年第3期42-49,共8页
In order to solve the fouling problems in boiling processes,a boiling system was designedby adding solid particles to the boiling liquid In this paper.both theoretical analyses andexperimental studies on the boiling h... In order to solve the fouling problems in boiling processes,a boiling system was designedby adding solid particles to the boiling liquid In this paper.both theoretical analyses andexperimental studies on the boiling heat transfer in such a three-phase flow boiling were carried out.Based on the analysis of heat transfer characters of this three-phase flow boiling,a mathematical mod-el for the heat transfer coefficient of flow boiling was developed.The experiments show that,in thepresence of particles the boiling heat transfer is enhanced and is about 2 times that of the vaporliquid two phase one with better flow stability.The fluidized particles rub the heat transfer wall toprevent and to clean the fouling. 展开更多
关键词 FLOW boiling fluidized SOLID PARTICLES FOULING
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A New Experimental Rig of Testing Flow Boiling Heat Transfer of Refrigerantand Lubricant Mixture 被引量:5
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作者 魏文建 丁国良 王凯建 《Journal of Shanghai Jiaotong university(Science)》 EI 2004年第4期62-67,共6页
This paper proposed a new experimental rig of testing flow boiling heat transfer of refrigerant and lubricant oil mixture. The quantity of oil in the test section can be controlled and regulated conveniently and accur... This paper proposed a new experimental rig of testing flow boiling heat transfer of refrigerant and lubricant oil mixture. The quantity of oil in the test section can be controlled and regulated conveniently and accurately by connecting separate lubricant oil circuit with test section in parallel. It was built up by retrofitting a multiple air-conditioner and installing three oil-separators in serials at the compressor outlet. And so the lubricant oil in the discharged refrigerant gas of compressor can be removed completely.The refrigerant flow rate through test section can be bypassed by the by-path circuit of indoor unit.This experimental rig has advantages such as on-line and continuous oil injection, short time of obtaining stability, flexible operation, simple control, which lead to high efficiency in the research of flow boiling heat transfer of refrigerant and lubricant oil mixture. 展开更多
关键词 REFRIGERANT flow boiling heat transfer lubricant oil
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Position Group Contribution Method for Predicting the Normal Boiling Point of Organic Compounds 被引量:7
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作者 王强 马沛生 +1 位作者 王昶 夏淑倩 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2009年第2期254-258,共5页
A new position group contribution model is proposed for the estimation of normal boiling data of organic compounds involving a carbon chain from C2 to C18.The characteristic of this method is the use of position distr... A new position group contribution model is proposed for the estimation of normal boiling data of organic compounds involving a carbon chain from C2 to C18.The characteristic of this method is the use of position distribution function.It could distinguish most of isomers that include cis-or trans-structure from organic compounds.Contributions for hydrocarbons and hydrocarbon derivatives containing oxygen,nitrogen,chlorine,bromine and sulfur,are given.Compared with the predictions,results made use of the most common existing group contribution methods,the overall average absolute difference of boiling point predictions of 417 organic compounds is 4.2 K;and the average absolute percent derivation is 1.0%,which is compared with 12.3 K and 3.2% with the method of Joback,12.1 K and 3.1% with the method of Constantinou-Gani.This new position contribution groups method is not only much more accurate but also has the advantages of simplicity and stability. 展开更多
关键词 normal boiling point PREDICTION position group contribution
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Mechanism of Calcium Carbonate Scale Deposition under Subcooled Flow Boiling Conditions 被引量:4
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作者 XING Xiaokai(邢晓凯) +3 位作者 MA Chongfang(马重芳) CHEN Yongchang(陈永昌) 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2005年第4期464-470,共7页
Fouling of heat transfer surfaces during subcooled flow boiling is a frequent engineering problem in process industries. It has been generally observed that the deposits in such industrial systems consist mainly of ca... Fouling of heat transfer surfaces during subcooled flow boiling is a frequent engineering problem in process industries. It has been generally observed that the deposits in such industrial systems consist mainly of calcium carbonate (CaCO3), which has inverse solubility characteristics. This investigation focused on the mechanism to control deposition and the morphology of crystalline deposits. A series of experiments were carried out at different surface and bulk temperatures, fluid velocities and salt ion concentrations. It is shown that the deposition rate is controlled by different mechanism in the range of experimental parameters, depending on salt ion concentration. At higher ion concentration, the fouling rate increases linearly with surface temperature and the effect of flow velocity on deposition rate is quite strong, suggesting that mass diffusion controls the fouling process. On the contrary, at lower ion concentration, the fouling rate increases exponentially with surface temperature and is independent of the velocity, illustrating that surface reaction controls the fouling process. By analysis of the morphology of scale, two types of crystal (calcite and aragonite) are formed. The lower the temperature and ion concentration, the longer the induction period and the higher the percentage of calcite nreciDitated. 展开更多
关键词 heat transfer FOULING calcium carbonate subcooled flow boiling
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Heat Transfer in Nucleate Pool Boiling of Binary and Ternary Refrigerant Mixtures 被引量:2
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作者 赵耀华 刁彦华 +1 位作者 鹤田隆治 西川日出男 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2004年第3期351-356,共6页
Heat transfer coefficients in nucleate pool boiling were measured on a horizontal copper surface for refrigerants, HFC-134a, HFC-32, and HFC-125, their binary and ternary mixtures under saturated conditions at 0.9MPa.... Heat transfer coefficients in nucleate pool boiling were measured on a horizontal copper surface for refrigerants, HFC-134a, HFC-32, and HFC-125, their binary and ternary mixtures under saturated conditions at 0.9MPa. Compared to pure components, both binary and ternary mixtures showed lower heat transfer coefficients.This deterioration was more pronounced as heat flux was increased. Experimental data were compared with some empirical and semi-empirical correlations available in literature. For binary mixture, the accuracy of the correlations varied considerably with mixtures and the heat flux. Experimental data for HFC-32/134a/125 were also compared with available correlated equation obtained by Thome. For ternary mixture, the boiling range of binary mixture composed by the pure fluids with the lowest and the medium boiling points, and their concentration difference had important effects on boiling heat transfer coefficients. 展开更多
关键词 pool boiling heat transfer nucleate pool boiling HFC-134A HFC-32 HFC-125
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