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Comparison of dilution effects of R134a and nitrogen on flammable hydrofluorocarbons

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Journal of Thermal Science 2009年第4期18卷 377-381页

作者： Zhenming Li maoqiong gong Jianfeng Wu Yuan Zhou Key Laboratory of Cryogenics Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing100190 China Graduate University of the Chinese Academy of Sciences Beijing 100039 China

An experimental apparatus has been built to measure the flammability limits of combustible gases based on Chinesenational standard GB/T 12474-90. The flammability limits of four binary mixtures of R161/R134a,R152a/R134a, R161/N2 and R152a/N2 were measured with this apparatus at atmospheric pressure and ambienttemperature. The fuel inertization points (FIP) of these mixtures can be found from the envelopes. Comparisonswere made with the literature data; good agreement for most measurements was obtained. R134a was found tohave a better dilution effect than nitrogen in reducing the flammability of hydrofluorocarbons.

关键词： Flammability limits fuel inertization point dilution effect

Effects of slip length and hydraulic diameter on hydraulic entrance length of microchannels with superhydrophobic surfaces

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Frontiers in Energy 2020年第1期14卷 127-138页

作者： Wenchi gong Jun SHEN Wei DAI Zeng DENG Xueqiang DONG maoqiong gong Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

This paper investigated effects of slip length and hydraulic diameter on the hydraulic entrance length of laminar flow in superhydrophobic *** investigations were performed for square microchannels with Re ranging between 0.1 and *** is found that superhydrophobic microchannels have a longer hydraulic entrance length than that of conventional ones by nearly 26.62%at a low *** dimensionless hydraulic entrance length slightly increases with the increasing slip length at approximately Re<10,and does not vary with the hydraulic diameter.A new correlation to predict the entrance length in square microchannels with different slip lengths was developed,which has a satisfying predictive performance with a mean absolute relative deviation of 5.69%.The results not only ascertain the flow characteristics of superhydrophobic microchannels,but also suggest that super hydrophobic microchannels have more significant advantages for heat transfer enhancement at a low Re.

关键词： laminar flow hydraulic entrance length super hydrophobic surface slip length hydraulic diameter

Numerical investigation on gas flow heat transfer and pressure drop in the shell side of spiral-wound heat exchangers

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Science China(Technological Sciences) 2018年第4期61卷 506-515页

作者： TANG QiXiong CHEN GaoFei YANG ZhiQiang SHEN Jun gong maoqiong Key Laboratory of Cryogenics Technical Institute of Physics and Chemistry Chinese Academy of SciencesBeijing 100190China Universiiy of Chinese Academy of Sciences Beijing 100049China

As a critical facility,spiral-wound heat exchanger was(SWHE)has the been widely used in many industrial *** A computational fluid dynamics(CFD)model employed with smallest periodic element results and periodic conditions to examine around the the characteristics tube of the shell side of *** simulation show that the heat transfer coefficients and initially mean increase absolute and subsequently decrease simulated 5%with heat radial angle because of the influence measured of backflow turbulent *** The deviation between is transfer coefficients and values for methane,drop,ethane,and are a mixture(methane/ethane)within when mean Reynolds number is over is *** the pressure the simulated results values smaller than the measured values,and the absolute on deviation within 9%.Numerical simulation also tubes indicate that the pressure drop the and heat of transfer coefficients angle the shell side and of SWHE heat decrease as the winding the angle of the *** Considering effect winding on pressure drops transfer coefficients,modified correlations of_=0.308Re^(0.64)Pr^(0.36)(1+sin)^(1.38 )and friction factor f_=0.435Re^(-0.133)(sin)^(-0.36),are *** Nu number with the experimental data,the maximum deviations for heat transfer coefficients and pressure drops are less than 5%and11%respectively.

关键词： spiral-wound heat exchangers CFD heat transfer pressure drop shell side

Nucleate Pool Boiling Heat Transfer of Pure Refrigerants and Binary Mixtures

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Journal of Thermal Science 2004年第3期13卷 259-263页

作者： Zhaofu SUN maoqiong gong Yanfeng QI Zhijian LI Jianfeng WU Technical Institute of Physics and Chemistry Chinese Academy of SciencesBeijing100080China Graduate School of the Chinese Academy of Sciences Beijing100039China

Heat transfer coefficients in nucleate boiling on a smooth flat surface were measured for pure fluids of R-134a, propane, isobutane and their binary mixtures at different pressure from 0.1 to 0.6 MPa. Series of experiments with different heat flux and mixture concentrations were carried out. The influences of pressure and heat flux on the heat transfer coefficient for different pure fluids were studied. Isobutane and propane were used to make up binary mixtures. Compared to the pure components, binary mixtures show lower heat transfer coefficients. This reduction was more pronounced as the heat flux increasing. Several heat transfer correlations are obtained for different pure refrigerants and their binary mixtures.

关键词： heat transfer pool boiling binary mixtures.

CO_2 solubility in aqueous solutions of N-methyldiethanolamine+piperazine by electrolyte NRTL model

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Science China Chemistry 2016年第3期59卷 360-369页

作者： Jicai Huang maoqiong gong Xueqiang Dong Xiaodong Li Jianfeng Wu Technical Institute of Physics and Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences School of Energy and Power Engineering Beihang University

Accurate modeling of the solubility behavior of CO_2 in the aqueous alkanolamine solutions is important to design and optimization of equipment and process. In this work, the thermodynamics of CO_2 in aqueous solution of N-methyldiethanolamine(MDEA) and piperazine(PZ) is studied by the electrolyte non-random two liquids(NRTL) model. The chemical equilibrium constants are calculated from the free Gibbs energy of formation, and the Henry's constants of CO_2 in MDEA and PZ are regressed to revise the value in the pure water. New experimental data from literatures are added to the regression process. Therefore, this model should provide a comprehensive thermodynamic representation for the quaternary system with broader ranges and more accurate predictions than previous work. Model results are compared to the experimental vapor-liquid equilibrium(VLE), speciation and heat of absorption data, which show that the model can predict the experimental data with reasonable accuracy.

关键词： N-methyldiethanolamine piperazine carbon dioxide electrolyte NRTL

Development of mobile miniature natural gas liquefiers

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Frontiers in Energy 2020年第4期14卷 667-682页

作者： Yanxing ZHAO maoqiong gong Haocheng WANG Hao GUO Xueqiang DONG Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100039China

With increasing consumption of natural gas(NG),small NG reservoirs,such as coalbed methane and oil field associated gas,have recently drawn significant *** to their special characteristics(e.g.,scattered distribution and small output),small-scale NG liquefiers are highly ***,the mixed refrigerant cycle(MRC)is suitable for small-scale liquefaction systems due to its moderate complexity and power *** consideration of the above,this paper reviews the development of mobile miniature NG liquefiers in Technical Institute of Physics and Chemistry(TIPC),*** effectively liquefy the scattered NG and overcome the drawbacks of existing technologies,three main improvements,i.e.,low-pressure MRC process driven by oil-lubricated screw compressor,compact cold box with the new designed heat exchangers,and standardized equipment manufacturing and integrated process technology have been *** development pattern of"rapid cluster application and flexible liquefaction center"has been eventually *** small-scale NG liquefier developed by TIPC has reached a minimum liquefaction power consumption of about 0.35 kW.h/Nm^(3).It is suitable to exploit small remote gas reserves which can also be used in boil-off gas reliquefaction and distributed peak-shaving of pipe networks.

关键词： natural gas mobile miniature liquefiers mixed refrigerant cycle vapor liquid equilibrium heat transfer

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深冷混合工质节流制冷机研究进展

化工学报 2014年第S2期65卷 9-18页

作者：公茂琼吴剑峰中国科学院低温工程学重点实验室中国科学院理化技术研究所北京100190

混合工质节流制冷机采用不同沸点组元构成多元混合物作制冷剂,适宜工作在从液氮温度至单级蒸汽压缩循环制冷温度下限的广阔温区,在生物医学、能源、材料甚至国防安全等领域具有广泛而重要的需求。本文简要回顾了作者团队围绕混合工质节... 详细信息

混合工质节流制冷机采用不同沸点组元构成多元混合物作制冷剂,适宜工作在从液氮温度至单级蒸汽压缩循环制冷温度下限的广阔温区,在生物医学、能源、材料甚至国防安全等领域具有广泛而重要的需求。本文简要回顾了作者团队围绕混合工质节流制冷技术方面近20年的研究工作,内容包括:工质筛选,回热换热器工作特性,混合工质节流制冷循环结构热力学优化分析,循环工质变浓度特性,及以-186℃节流制冷深冷冰箱、撬装天然气液化为代表的应用研究等。

关键词：深冷混合工质节流制冷工质热物性回热换热器变浓度特性热力循环优化分析

两相流中相积存造成多元混合制冷剂浓度变化分析

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制冷学报 2006年第4期27卷 10-12页

作者：公茂琼中国科学院理化技术研究所北京100080

因多相流动中汽液速度差而造成相积存(Holdup)是深冷混合工质节流制冷系统中混合物浓度偏析的一个重要因素。建立了因相积存造成浓度变化的计算模型,采用Palmer对Beggs-Brill-Moody关联式的修正式,详细考察了管道倾角及流体温度对深冷... 详细信息

因多相流动中汽液速度差而造成相积存(Holdup)是深冷混合工质节流制冷系统中混合物浓度偏析的一个重要因素。建立了因相积存造成浓度变化的计算模型,采用Palmer对Beggs-Brill-Moody关联式的修正式,详细考察了管道倾角及流体温度对深冷多元混合物因汽液相积存异造成的浓度偏析影响。计算结果表明,管道倾角对积存具有显著影响,其中倾斜向上会显著增加积存,造成混合物浓度显著变化。浓度变化发生在两相区,并随温度变化导致不同组分的浓度变化趋势不同。

关键词：工程热物理浓度变化计算分析相积存多元混合工质

R23+R116系汽液相平衡的测量与数据拟合

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化工学报 2008年第2期59卷 269-275页

作者：张宇公茂琼吴剑峰中国科学院理化技术研究所北京100080

利用气相循环法的实验装置测量了R23(三氟甲烷)+R116(六氟乙烷)二元体系在5个温度(194.33,199.71,214.90,229.63,244.94K)下的汽液相平衡数据,利用Peng-Robinson(PR)状态方程和Soave-Redlich-Kwong(SRK)状态方程分别与Huron-Vidal(HV)混合规则相结合的两个模型对实验数据进行关联,提出了模型参数的关联式,并将两个模型的计算结果进行对比。结果表明:PR-HV模型对此二元系的关联结果较好,其压力计算值与实验值的相对偏差的平均值为0.29%,摩尔分数计算值与实验值的绝对偏差的平均值为0.0006。

关键词：三氟甲烷六氟乙烷汽液相平衡