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Experimental study on condensation heat transfer of ethanol-water mixtures on a vertical mini-tube

AIP Conference Proceedings 2012年第1期1428卷 35-42页

作者： XiPing Chen JunJie Yan RongHai Huang JiPing Liu State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiao tong University Xi'an City 710049 China

Experiments were carried out to investigate condensation of ethanol-water vapor mixtures on a vertical mini-tube with outer diameter of 1.032mm. The length, inter diameter of the tube was 110mm, 0.727mm, respectively. The tests were performed at a wide range of ethanol concentrations (Cv=0%, 1%, 2%,5%) and varied velocity of vapor (Uv=2m/s, 4m/s, 6m/s) and pressure (Pv=31.2kPa, 47.4kPa, 84.5kPa). With the change of the vapor-to-surface temperature difference, the heat transfer coefficients revealed nonlinear characteristics with the peak values under all ethanol mass fractions of vapor. The heat transfer coefficients decreased with increasing ethanol mass fraction of vapor.

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Analysis of Different Control Strategies Considering Individual Regulation of Heat User 3

Analysis of Different Control Strategies Considering Individ...

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3rd International Conference on Electrical engineering and Mechatronics Technology, ICEEMT 2023

作者： Xun, Zhiwei Wang, Huijie Wang, Liyuan Yang, Long Gao, Yunfang Liu, Ming Guoneng Jinjie Energy Co. Ltd Yulin China Xi'an Jiaotong University Xi'an China Xi'an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an China

ISBN: (纸本)9798350303698

In the process of outdoor temperature change, it is beneficial to improve the comfort of thermal users to formulate adjustment and control strategies according to the actual needs of each user. In this paper, different adjustment modes are established according to the thermal comfort of users, and the control strategies of rising and cooling within 0, 30 and 60 minutes are proposed, and the indoor temperature control effect and heating energy consumption of each adjustment mode under different control strategies are analyzed. The results show that: in different modes, when the rise and cooling time increase, compared with the design room temperature, the indoor temperature difference under the control mode is smaller, but the time needed to reach stability is longer. At the same time, the total heat load is unchanged, but the total pump work decreases. © 2023 IEEE.

关键词： Energy utilization

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Experimental Study on Non-Isothermal Mixing Characteristics of Water in T-Junction

Experimental Study on Non-Isothermal Mixing Characteristics ...

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2024 Academic Conference of China Instrument and Control Society, ACCIS 2024

作者： Liu, Shuhan Guo, Wencang Lei, Xianliang Yuan, Zhaojun Meng, Shuqi Jin, Desheng Xi'an Jiaotong University State Key Laboratory of Multiphase Flow Engineering Xian China China Nuclear Power Technology Research Institute Co. Ltd. Shen Zhen Guangdong China

ISBN: (纸本)9798350350326

T-junction is an essential component in piping system of various thermal systems. When hot and cold fluid mixing in the T-junction, several compound mechanisms (like turbulent mixing, turbulent penetration, fluid stratification) make the mixing characteristics more complex. To clearly reveal such mixing mechanism with non-isothermal fluids, an experimental study was conducted with Ultrasound Doppler Velocimetry (UDV) and fast-response thermocouples bundle. The results show that the local velocity uncertainty of the UDV is within 10%, the uncertainty of the thermocouple bundle is 0.5°C, and the response time is 66.7 ms. After verification, the mixing characteristics between the main and branch pipe under different momentum ratios and temperature differences were discussed. It is shown that as the momentum ratio decreases, the location of the most intense radial temperature fluctuations and velocity fluctuations shifts towards the lower wall. At the same time, the peak flow rate in the cross-section increases by 35.7% and the main branch fluid mixing is more homogeneous. As the temperature difference increases, the thermal stratification is more pronounced and the velocity fluctuation peak moves towards the upper wall of the pipe. © 2024 IEEE.

关键词： Thermocouples

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Experiment of condensation in T-junction: Steam-water flow in water-injected condition 16

Experiment of condensation in T-junction: Steam-water flow i...

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16th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2015

作者： Ren, W.Y. Yu, G.J. Bian, J.W. Tian, W.X. Su, G.H. Qiu, S.Z. Fu, X.L. School of Nuclear Science and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiao Tong University No. 28 Xianning West Road Xi'an710049 China State Nuclear Power Software Development Center Beijing102206 China National Key Laboratory of Nuclear Power Software Beijing10226 China

ISBN: (纸本)9781510811843

Condensation of two-phase flow inside a tube within sub-cooled coolant injected show a complicated phenomenon which affects both the pressure drops from the upstream to downstream and the void fraction distribution in tube. This phenomenon always appears in the T-junction which kind of structure could be found in nuclear power plants design. The investigation about injection to two-phase flow in this structure can help us predict the hydrodynamic phenomenon of condensation heat transfer. Distribution of the fluid temperature and heat transfer coefficient (HTC) due to fluid-fluid mixing and steam condensation had been considered to be a significant process which is included in the pressurized thermal shock (PTS) research. Previous researches had built the integral effect test to analysis the effect of thermal mixing. However, the practical condensate process in T-junction injected is too hard to be predict accurately, which is contributed to the structure, the geometric dimension, the mass flow rate between the main and branch pipe, the flow patterns, the void fraction of two-phase flow, temperature of flow, pressure, etc. We analyzed the process of cooling water injecting from the branch pipe into a horizontal main pipe, and also focus on the phenomena of water injection in steam or different flow patterns. We had set some thermo couples inserting to the tube to keep observing the temperature field inside. The initial conditions of the experiment about the flow pattern before the injection includes stratified flow, wavy flow, annular flow and dispersed flow. We also took the heat dissipation between the test facility and surround into consideration. The experiment is a separate effect test program which based on the phenomena about condensation in T-junction with 45° incidence injection and progressed on ordinary pressure.

关键词： Two phase flow

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Numerical simulation of predicting and reducing solid particle erosion of solid-liquid two-phase flow in a choke

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Petroleum Science 2009年第1期6卷 91-97页

作者： Li Guomei Wang Yueshe He Renyang Cao Xuewen Lin Changzhi Meng Tao State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇an Shaanxi 710049 China China Special Equipment Inspection and Research Institute Beijing 100013 China School of Transport ＆ Storage and Civil Engineering China University of Petroleum Qingdao Shandong 266555 China Petroleum Exploration and Production Research Institute Sinopec Beijing 100083 China

Chokes are one of the most important components of downhole flow-control equipment. The particle erosion mathematical model, which considers particle-particle interaction, was established and used to simulate solid particle movement as well as particle erosion characteristics of the solid-liquid two-phase flow in a choke. The corresponding erosion reduction approach by setting ribs on the inner wall of the choke was advanced. This mathematical model includes three parts： the flow field simulation of the continuous carrier fluid by an Eulerian approach, the particle interaction simulation using the discrete particle hard sphere model by a Lagrangian approach and calculation of erosion rate using semiempirical correlations. The results show that particles accumulated in a narrow region from inlet to outlet of the choke and the dominating factor affecting particle motion is the fluid drag force. As a result, the optimization of rib geometrical parameters indicates that good anti-erosion performance can be achieved by four ribs, each of them with a height （H） of 3 mm and a width （B） of 5 mm equaling the interval between ribs （L）.

关键词： Solid-liquid two-phase flow discrete particle hard sphere model choke erosion rate antierosion numerical simulation

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Influence of Oxy-fuel Atmosphere on Microscopic Physical-Chemical Properties of High-alkali Ash at Softening Temperature

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Energy Procedia 2017年 142卷 3240-3243页

作者： Chang’an Wang Hanqing Li Chenzhao Zhu Tao Han Yinhe Liu Lei Deng Defu Che State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China

The utilization of high-alkali coals in Zhundong coalfield with oxy-fuel combustion technology has a great potential, however, the ash fusion properties of high-alkali coals are still unclear. Here, we studied the influence of oxy-fuel atmosphere on the microscopic properties of high-sodium ash. The change from air to oxy-fuel condition has a negligible influence on ash fusion temperatures, but exhibits certain impact on physical-chemical properties of high-alkali ash. Oxygen content presents a primary effect on the microscopic morphology of ash at softening temperature.

关键词： high-alkali coal oxy-fuel combustion CO 2 capture microscopic properties SEM

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High loading cotton cellulose-based aerogel self-standing electrode for Li-S batteries

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Science Bulletin 2020年第10期65卷 803-811,M0003页

作者： Heng Mao Limin Liu Lei Shi HuWu Jinxin Lang Ke Wang Tianxiang Zhu Yiyang Gao Zehui Sun Jing Zhao Guoxin Gao Dongyang Zhang Wei Yan Shujiang Ding Xi’an Key Laboratory of Sustainable Energy Materials Chemistry State Key Laboratory of Electrical Insulation and Power EquipmentDepartment of Applied ChemistrySchool of ScienceXi’an Jiaotong UniversityXi’an 710049China Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049China

Lithium-sulfur(Li-S) batteries have attracted considerable attention due to their high energy density(2600 Wh kg-1). However, its commercialization is hindered seriously by the low loading and utilization rate of sulfur cathodes. Herein, we designed the cellulose-based graphene carbon composite aerogel(CCA) self-standing electrode to enhance the performance of Li-S batteries. The CCA contributes to the mass loading and utilization efficiency of sulfur, because of its unique physical structure: low density(0.018 g cm-3), large specific surface area(657.85 m2 g-1), high porosity(96%), and remarkable electrolyte adsorption(42.25 times). Compared to Al(about 49%), the CCA displayed excellent sulfur use efficiency(86%) and could reach to high area capacity of 8.60 mAh cm-2 with 9.11 mgS loading. Meanwhile,the CCA exhibits the excellent potential for pulse sensing applications due to its flexibility and superior sensitivity to electrical response signals.

关键词： Cellulose-based graphene aerogel Self-standing electrode High sulfur loading Lithium-sulfur battery Pulse sensing

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Measurement of current distributions in a PEM fuel cell with interdigitated flow Fields

Measurement of current distributions in a PEM fuel cell with...

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7th Symposium Devoted to Proton Exchange Membrane Fuel Cells - 212th ECS Meeting

作者： Zhang, G.S. Ma, B. Shang, D.H. Guo, L.J. Sun, H. Liu, H.T. State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049 China Department of Mechanical and Aerospace Engineering University of Miami Coral Gables FL 33124 United States Electrochemical Society

ISBN: (纸本)9781566775823

Current distributions in a PEM fuel cell with interdigitated flow fields were measured with the current distribution measurement gasket technique. The measurement results showed that current density distribution in a fuel cell with interdigitated flow fields is much more uniform than those observed in a fuel cell with serpentine flow fields, especially at low reactant gas flows. The more uniform current distribution can be attributed to more uniform flow distribution over the flow fields. Measurement results also showed that interdigitated flow fields have very good water removal capability and no flooding phenomena were observed at high humidification temperatures;while at low humidification temperatures, the effect of drying is more severe than that found in serpentine flow fields. © The Electrochemical Society.

关键词： Proton exchange membrane fuel cells (PEMFC)

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Experimental study on combustion, ash fusibility and slagging propensity during co-combustion of organic solid waste and lignite

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Journal of the Energy Institute 2023年 106卷

作者： Liu, Hu Wang, Yancheng Xue, Jingwen Zhang, Yankang Yu, Pengfei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 China

Rapidly growth of organic solid waste (OSW) has caused serious social and environmental problems. Incineration as one of the most good public acceptance and environmentally friendly method attains increasing attention. In this study, the co-combustion characteristics of OSW and lignite, including the ignition and burnout temperature, ash melting and slagging propensity were studied. The experimental results show that the ignition temperature almost remains stable while the burnout temperature of the blends decreases as the increase of the OSW blending ratio, since the heat release during volatile combustion is beneficial for the burnout of coal char, but the polymer may melt and block the pores of the coal char at high temperature when the OSW blending ratio is higher than 30%. Besides, the slagging propensity of blending fuel is severe when the OSW blending ratio is 30%, and special attention should be paid to avoid slagging during the combustion process. © 2022 Energy Institute

关键词： Lignite

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Rapid Methane Hydrate Formation in Open-Cell Copper Foam 4th

Rapid Methane Hydrate Formation in Open-Cell Copper Foam

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4th International Technical Symposium on Deepwater Oil and Gas engineering and 3rd International Youth Forum on Gas Hydrate, DWOG-Hyd 2021

作者： Wang, Jiajie Yang, Liang Shao, Xinxin Zhang, Hao School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology Shanghai200093 China

ISBN: (纸本)9789811909597

Rapid methane hydrate formation with high gas storage capacity is very important for the application of natural gas hydrates technology. Three pieces of open-cell copper foam (CF) with different pore densities (or pores per inch, PPI) herein were immersed in sodium dodecyl sulfate (SDS) solution for enhancing methane storage in solid hydrate. The promotion effects of CF on the methane hydrate formation in the metal-embedded systems were investigated via an unstirred tank reactor. The results demonstrated that the surface of CF skeleton is covered with abundant micro holes and micro grooves, which can provide many metal nuclei for gas-water crystallization. The nest-like metal skeleton acts as crisscross "highway" for the crystallization heat transfer. Methane hydrate was quickly formed in the SDS/CF systems, but CF with the pore densities of 5 and 30 PPI was not favorable for conversion of more water to hydrate. Compared with these two composite systems, the SDS solution with the 15 PPI CF were able to store more methane at a faster formation rate. A theoretical model based highly porous two-phase systems was used to predict the effective thermal conductivity (ETC) of the metal foam filled with hydrate. It was found that the ETC of the hydrate/CF composite was significantly enhanced by employing CF matrix, and the low pore density CF had a more positive impact on improving the ETC of the composite. Further comparative experiments conducted at various pressures indicated that the solutions with 15 PPI CF exhibited higher methane storage capacities and larger hydration rates than the simple SDS solution, especially at the low pressure. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Sodium dodecyl sulfate

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