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Dynamic Analysis and Optimization of Heat Transfer Performance During Electrospray Cooling with Ethanol-R141b Mixture

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SSRN 2022年

作者： Tian, Jiameng Kong, Lingwen Li, Bufa Wang, Junfeng Chen, Bin Xiong, Junhui School of Energy and Power Engineering Jiangsu University Zhenjiang212013 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Zhejiang Ningbo315201 China

Electrospray (ES) cooling that relies on Coulomb forces for energy-efficient liquid atomization is promising to meet the requirement of high-heat-flux thermal dissipation for micro-sized electronics under relative low... 详细信息

关键词： Ethanol

Additional interfacial force in lattice Boltzmann models for incompressible multiphase flows

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Physical Review E 2012年第2期85卷 026704-026704页

作者： Q. Li K. H. Luo Y. J. Gao Y. L. He Energy Technology Research Group School of Engineering Sciences University of Southampton Southampton SO17 1BJ United Kingdom Center for Combustion Energy Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Thermal Engineering Tsinghua University Beijing 100084 China Department of Zoology University of Cambridge Cambridge CB2 3EJ United Kingdom National Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China

The existing lattice Boltzmann models for incompressible multiphase flows are mostly constructed with two distribution functions: one is the order parameter distribution function, which is used to track the interface between different phases, and the other is the pressure distribution function for solving the velocity field. In this paper, it is shown that in these models the recovered momentum equation is inconsistent with the target one: an additional force is included in the recovered momentum equation. The additional force has the following features. First, it is proportional to the macroscopic velocity. Second, it is zero in every single-phase region but is nonzero in the interface. Therefore it can be interpreted as an interfacial force. To investigate the effects of the additional interfacial force, numerical simulations are carried out for the problem of Rayleigh-Taylor instability, droplet splashing on a thin liquid film, and the evolution of a falling droplet under gravity. Numerical results demonstrate that, with the increase of the velocity or the Reynolds number, the additional interfacial force will gradually have an important influence on the interface and affect the numerical accuracy.

关键词： COMPUTER simulation LATTICE Boltzmann methods multiphase flow INCOMPRESSIBLE flow (Fluid mechanics) DISTRIBUTION (Probability theory) MOMENTUM (Mechanics)

Experimental Study on the Performance Difference of Pulsating Heat Pipe Using R170 and R134a as Working Fluids

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SSRN 2023年

作者： Song, Yuxin Chen, Xi Zhan, Jingru Zhang, Hua School of Energy and Power Engineering University of Shanghai for Science and Technology 516 Jungong Road Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology 516 Jungong Road Shanghai200093 China

The pulsating heat pipe (PHP), as a type of heat pipes, is a flexible heat transport device with highly efficient conduction, which is widely used in many fields including aerospace, waste heat recovery, cryogenic refrigerator and so on. The working fluids have an important effect on the thermal performance of PHPs. This study experimentally compares a PHP with R170 and R134a as the working fluids, respectively, examining temperature fluctuations, thermal resistance, and temperature differentials. Findings indicate that R170 PHP exhibits sensitivity to heat input (HI), with temperature fluctuations stagnating at 70 W. Increasing the filling ratio (FR) from 30% to 60% results in a steady rise in R170 PHP thermal resistance. While R170 PHP thermal resistance increases with higher inclination angles (IAs), it does so to a lesser extent compared to R134a PHPs. In the temperature region of -20 ℃ to 0 ℃, both R170 and R134a perform similarly. However, as the working temperature (WT) decreases, R170 PHP outperforms R134a PHP. Overall, the thermal performance of R170 PHP is superior to R134a PHP. This study provides reference value for the future research of PHPs in the temperature region of -60 ℃ to 0 ℃. © 2023, The Authors. All rights reserved.

关键词： Heat resistance

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半稳定单原子催化剂增强光热协同催化

Science Bulletin 2024年第12期69卷 1833-1838页

作者：付亦葳吕科见王怡司亦涛师进文李乃旭周致富刘茂昌 International Research Center for Renewable Energy State Key Laboratory of Multiphase FlowXi’an Jiaotong UniversityXi’an 710049China School of Chemistry and Chemical Engineering Southeast UniversityNanjing 211189China Suzhou Academy of Xi’an Jiaotong University Suzhou 215123China

Single-atom catalysts(SACs)have been extensively studied in photocatalysis,electrochemistry,and ***,their utilization in photothermal catalysis is still in the infancy and is worth investigating,as these catalysts are... 详细信息

关键词： field. catalysis. 单原子催化剂

Comprehensive Parameter Analyses on Steam-Air Condensation at Equal- Height-Difference Natural Circulation Loop Under Large Air Mass Fraction

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SSRN 2024年

作者： Chen, Weixiong Wang, Han Li, Sinian Kai, Hui Zhao, Quanbin Li, Shaodan Wang, Jinshi State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Missile Engineering College Rocket Force University of Engineering 710025 China Science and Technology on Thermal Energy and Power Laboratory Wuhan 2nd Ship Design and Research Institute Wuhan430205 China

With the development of small-sized reactors, a passive containment cooling system (PCCS) named equal-height difference natural circulation loop (EHDNCS) has been developed. Experiments were conducted at higher air mass fractions to evaluate the condensation heat transfer coefficient (HTC) as a function of steam-air mixture pressure, air mass fraction, and wall subcooling. The results indicate that the condensation HTC decreases with increasing air mass fraction and increases with increasing steam-air mixture pressure in the containment. The relationship between condensation HTC and air mass fraction gradually transitions from non-linear to linear as the steam-air mixture pressure increases. The condensation HTC increases with increasing wall subcooling;However, for air mass fractions greater than 75%, the condensation HTC remains nearly constant with changes in wall subcooling. A quantitative relationship between the condensation HTC and the height of the PCCS (sum of riser height and 0.5 times heat exchanger height) has been derived by calculating the cooling water flow driving force and resistance in the natural circulation loop. The applicable conditions for optimizing the riser height and the initial ratio of the riser to heat exchanger height to enhance the heat transfer power of the PCCS were proposed. Based on the experimental results, an empirical correlation equation for predicting the condensation HTC for PCCS with EHDNCS is established, with a prediction deviation within ±31%. © 2024, The Authors. All rights reserved.

关键词： Heat exchangers

Investigation of the Solar-Driven Chemical Looping Methane Dry Reforming on Rh-Doped LaCeO3.5 Oxygen Carrier

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SSRN 2024年

作者： Li, Peng Gai, Zhongrui Zhang, Jinrui Rao, Qiong Tang, Sanli Shen, Yuanhui Pan, Ying Jin, Hongguang Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China University of Chinese Academy of Sciences Beijing100049 China

The feasibility of a solar-driven chemical looping dry reforming of methane (DRM) process, which converts solar energy and methane into syngas via a looping material oxygen carrier is investigated experimentally. Thermogravimetric analysis (TGA) experiments were firstly carried out to verify the effect of the Rh-doped LaCeO3.5 which were synthesized via modified Pechini method and incipient wetness method and the result shows that Rh greatly improved the reaction kinetics. Photo-TGA experiments were conducted to evaluate the light effect in chemical looping DRM. Under the light condition, the Rh-doped LaCeO3.5 shows higher methane conversion, oxygen extraction rate and CO selectivity compared with the undoped one, decreasing the apparent activation energy of the reaction at the same time. Insights obtained from the UV-Vis spectroscopy verified that the surface Rh under the light could promote the activation of surface methane species and increase the light absorbance. Meanwhile, the FEM methods were used to obtain the distributions of the temperature fields of the photo-TGA reactor through the calculation of the coupling of the fluid, reaction and temperature fields. In this way, the conversion mechanism of the solar, heating and chemical energy was illustrated and furthermore, the calculated surface reaction rate and the variation tendency of the outlet-gas were consistent with the experimental results. Through the integration of solar energy, a high methane to solar fuel conversion efficiency could be achieved. The proposed process has the potential to produce solar fuels at high efficiency with reduced carbon footprint. © 2024, The Authors. All rights reserved.

关键词： Methane

Experimental Study on Stable Jet Impact Process Under Simulated Pipeline Rupture

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Experimental Study on Stable Jet Impact Process Under Simula...

Student Conference on Research and Development (SCOReD)

作者： Zhang Tao Bi Qincheng Zhao Jinle Wang Teng Chen Jingrong Feng Fan State Key Lab Multiphase Flow Power Engn Xi’an Jiaotong University Xi’an Shaanxi China School of Energy Power and Mechanical Engineering North China Electric Power University Bao’ding Hebei China

ISBN: (数字)9798350318821

ISBN: (纸本)9798350318838

In this study, an advanced experimental system was utilized that incorporated heating, jetting, recycling, and cooling capabilities to ensure the successful execution of stable jet impact experiment that simulating a pipeline complete rupture. High-temperature resistant tempered glass was employed in the experimental system to realize the visibility. During the experiment, 8mm pipes/nozzles of varying lengths were employed as the test sections, and jetting phenomena when the import status is single-phase cold water or two-phase mixture at 0-2MPa were obtained by high-resolution photos. Additionally, the shape of the jet cone and the impact force exerted on the target plate were meticulously analyzed after the working fluid under different state parameters jetting into an atmospheric pressure environment through pipes/nozzles. The research also focused on the variation trend in the magnitude of the jet-impact force, as a function of inlet pressure and temperature, target plate distances, and length-to-diameter ratios. The research findings revealed that cold water(below 100°C), sub-cooled water(above 100°C but not reaching saturation temperature), and two-phase steam-water mixture exhibited distinct jet cone shapes during the jetting process, resulting in varying distributions of the jet force. Furthermore, the distance from the spout to the target plate and the length-to-diameter ratio significantly influenced the magnitude of the jet impact force.

关键词： Resistance Visualization Temperature distribution Fluids Shape Force Pipelines

Study in steam-water two-phase flow heat transfer at high mass velocity of flow in vertical helical coiled tube

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Kung Cheng Je Wu Li Hsueh Pao/Journal of engineering Thermophysics 2008年第3期29卷 423-428页

作者： Guo, Meng Zhao, Liang Mao, Yu-Fei Zhen, Fei-Qiang Zhang, Wen-Bin Guo, Lie-Jin Peng, Xiao-Feng State Key Lab. of Multiphase Flow in Power Engineering Xi'an 710049 China

Experiments were conducted to further understand the heat transfer in two-phase flow in vertical helically-coiled tubes. The experiments covered a wide range of pressure 8.0-15.0 MPa, mass flow rate 2500-4000 kg/(m2s), heat flux 200-800 kW/m2. The experimental segment is 2.335 meter long and made by φ14 × 2 mm steel tube. The diameter ratio D/d is 30.1. Through analyzing the influence of heat flux, mass velocity on average heat transfer coefficient, we acknowledge the activities of nucleate boiling and forced convection two mechanism on steam-water two-phase heat transfer in helical coils tubes at high mass flow rate. The average and local heat transfer coefficient correlations were obtained. At high mass flow rate conditions, the effect of heat transfer in the steam-water two-phase flow in helically coils is inclined to that of straight tube at same conditions and the results are compared.

关键词： Heat exchangers

Microwave-assisted synthesis of bimetallic NiCo-MOF-74 with enhanced open metal site for efficient CO 2 capture

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Environmental Functional Materials

Environmental Functional Materials 2022年第3期1卷 253-266页

作者： Changwei Chen Mohammadreza Kosari Meizan Jing Chi He State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi PR China Department of Chemical and Biomolecular Engineering Faculty of Engineering National University of Singapore 10 Kent Ridge Crescent 119260 Singapore Department of Chemistry Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education Tsinghua University Beijing PR China National Engineering Laboratory for VOCs Pollution Control Material & Technology University of Chinese Academy of Sciences Beijing 101408 PR China

Metal–organic frameworks (MOFs) containing two different inorganic metal nodes (known as bimetallic MOFs) could exhibit enhanced CO 2 adsorption compared to their monometallic counterparts. Herein, a series of bimetallic NiCo-MOF-74 synthesized by microwave-assisted method were investigated for CO 2 adsorption. It was revealed that narrow micropore channel with open metal site (OMS) of the bimetallic NiCo-MOF-74 influence CO 2 binding affinity and CO 2 /N 2 adsorption. The CO 2 uptake of Ni 1 Co 1 -MOF-74 at 0 °C and 1 bar (100 kPa) was 8.30 mmol g −1 which is higher than those of Ni-MOF-74 (3.99 mmol g −1 ), Ni 6 Co 1 -MOF-74 (3.62 mmol g −1 ), Ni 1 Co 6 -MOF-74 (6.40 mmol g −1 ) and Co-MOF-74 (5.03 mmol g −1 ). While this could be related to the high specific surface area of Ni 1 Co 1 -MOF-74, Ni 1 CO 2 -MOF-74 with relatively low specific surface areas still shows good CO 2 adsorption capacity up to 5.70 mmol/g, which is higher than those of adsorbents Ni-MOF-74, Ni 6 Co 1 -MOF-74 and Co-MOF-74, indicating that adsorption performance mainly relies on coordinated metals. Ni 1 Co 1 -MOF-74 showed remarkable recyclability performance, ranking selectivity of CO 2 /N 2 reach up to 34, and suitable isosteric heat (31–23 kJ mol −1 ), manifesting a great probability for industrial CO 2 capture. As revealed, incorporated Ni 2+ /Co 2+ nodes within Ni 1 Co 1 -MOF-74, which are acting as active and open sites for CO 2 capture, led to the synergetic effects comprising of micropores as well as dense dual-metal sites.

关键词： Bimetallic metal–organic frameworks NiCo-MOF-74 Microwave-assisted synthesis Open metal site CO 2 capture