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Numerical Investigation on the Thermal-Hydraulic Performance of a Cryogenic Printed Circuit Heat Exchanger for Liquid Air Energy Storage

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SSRN 2022年

作者： Yu, Pengfei Liu, Hu Xue, Jingwen Zhang, Yankang Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'An710049 China

The liquid air energy storage integrated with liquefied natural gas regasification is a promising large-scale storage method, but its development is limited by the lack of the thermal-hydraulic data of the cryogenic printed circuit heat exchanger. In this paper, a reduced numerical model for conjugate heat transfer was established, and the effect of the inclined angle (0°, 15°, 30°, 45°, and 60°) was investigated. The minimum internal temperature approach for optimal system operation is approximately 6 K, located in the middle of the heat exchanger. The nature of local flow and heat transfer was analyzed by quantifying the vortex strength and visualizing the vortex core. Results indicate that the evolution of Dean vortices plays a crucial role in heat transfer augmentation. The secondary flow caused by the elbow forces the velocity and temperature cores to strike the windward side periodically, which disturbs the boundary layer and enhances the fluid mixing. Entropy production analysis shows that the thermal entropy generation has a dominant share of the irreversibility. The zigzag channel with an inclined angle of 45° yields the best comprehensive performance since the irreversibility is reduced by augmenting the heat transfer. © 2022, The Authors. All rights reserved.

关键词： Air

Water Washing of Biomass and Biochar

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SSRN 2022年

作者： Huang, Xiaole Tie, Yuan Jiang, Jiahao Deng, Lei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China

To investigate the differences of organics composition between leachates of biomass and biochar, four biomass materials and the corresponding biochar are water washed. The distributions of organic compounds in leachates are characterized by GC-MS. Raw and washed biomass, and biomass leachates dried at 333 K are sent for TG/DTG analysis. The results show that considering the content of aromatic hydrocarbons, corn and sorghum stalk are referred to be washed after high-temperature pyrolysis at 303 K, with the value of 11% and 29.95% respectively. Wheat straw and rice husk are proposed to wash directly. Considering the alkanes, cycloalkanes and heterocyclic hydrocarbons contents in leachates, it is proposed to washing low-temperature pyrolyzed biochar. It is recommended to wash biomass directly to inhibit acidic organics release. Washed and raw biomass have similar DTG curves. The combustion stage of dried leachate is more complicated, with one or two peaks during the third stage. The activation energy follows an order of washed biomass > raw biomass > biomass leachate. © 2022, The Authors. All rights reserved.

关键词： Biomass

Water Washing of Biomass and Biochar

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SSRN 2022年

To investigate the differences in organics composition between leachates of biomass and biochar, four biomass materials and the corresponding biochar are water washed. GC-MS is employed to characterize the distributions of organic components in leachates. Raw and washed biomass, and biomass leachates dried at 333 K are sent for TG/DTG analysis. The results show that corn and sorghum stalks should be washed after the high-temperature pyrolysis at 303 K, with aromatic hydrocarbon contents of 11.00% and 29.95%, respectively. It is proposed that wheat straw and rice husk should be washed directly. Considering the contents of alkanes, cycloalkanes, and heterocyclic hydrocarbon in leachates, biomass should be pyrolyzed at a relatively low temperature and then be washed. It is recommended to wash biomass directly to inhibit the acidic organic release. Washed and raw biomass samples have the similar DTG curves. The combustion of dried leachate is more complicated, with one or two peaks during the third stage. The activation energy follows an order of washed biomass > raw biomass > biomass leachate. © 2022, The Authors. All rights reserved.

关键词： Biomass

A simple analytical model to predict liquid unloading in the horizontal gas well

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Journal of Hydrodynamics 2021年第5期33卷 1056-1064页

作者： Zhi-bin Wang Jin-quan Ling Tian-li Sun Hong-yan Shi Guo Zhu State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChendu 610500China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China No 2 Gas Production PlantSouthwest Oil and Gas CompanySINOPECLangzhong 637400China Infrastructure Department Southwest Oil and Gas CompanySINOPECChengdu 610041China

An accurate prediction of the critical gas velocity for the liquid loading is of great importance for operators to select the tubing diameter for the newly drilled gas wells,or to optimize the production rate for production *** is clear from previous experimental studies of the liquid entrainment rate in the gas core that the liquid is mainly carried in the form of film under the critical condition of the liquid loading *** is more reasonable to establish a mathematical model based on the film reversal rather than based on the droplet *** our previous paper entitled“Prediction of the critical gas velocity of liquid unloading in the horizontal gas well”,a new analytical model was established based on the force balance between the gas-liquid interfacial friction force and the bottom film gravity,but the model is not very convenient to use because of the complexity of calculating the average film *** the present study,a new method is proposed to calculate the average film thickness from the bubble drift velocity in the mixture,so the new analytical model becomes much easier to *** new analytical model is evaluated against 103 sets of experimental data,the data in 124 vertical gas wells and one horizontal gas ***,the effect ofthe liquid loading on the production of the horizontal gas well is also analyzed.

关键词： Horizontal gas well inclined annular flow liquid-film thickness liquid unloading

Study of Saturated Pool Boiling Heat Transfer Characteristics of R1233zd(E) on Aluminum-Based Micro-Pin Finned Surfaces

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SSRN 2024年

作者： Yang, Xiaoping Bu, Shichao Jiang, Zhuye Chen, Hongqiang Sun, Zhen Zhang, Yonghai Wei, Jinjia School of Chemical Engineering and Technology Xi’an Jiaotong University Shaanxi Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China State Key Laboratory of Mobile Network and Mobile Multimedia Technology ZTE Corporation hillsides China

With the continuous development of chip integration and information technology, the heat dissipation has become a major limitation on the performance of electronic devices such as 5G base station, data center and so on, and meanwhile a challenge of conventional single-phase convection cooling methods. Boiling is prospective in high heat flux cooling and energy saving due to the usage of latent heat. R1233zd(E), an environmentally friendly refrigerant (GWP=1, ODP=0) with a freezing point of -107°C, is a potential working fluid in phase-change heat sinks for geographical applications. Nevertheless, the poor boiling performance of R1233zd(E) on plain surface due to the limitation in thermophysical properties must be enhanced. Moreover, conventional heat sinks are mostly copper-based, which are inconvenient for transportation and installation, and costly for production as well. In this work, micro pin fins in the range of 100-500 μm are fabricated on the aluminum surface to enhance the pool boiling of R1233zd(E). Moreover, the influence of their size and saturation pressure on the bubble behavior, critical heat flux (CHF) and heat transfer coefficient (HTC) is experimentally and theoretically investigated. The results show that the increase of pressure, as well as the ensuing various nucleation site and capillary effect to rewet the evaporation region, can lead to an increase in the CHF and HTC. Notably, the 150-200 μm micro pin-finned surfaces reaches the highest CHF and 100 μm one owns the highest HTC, which is 214% and 383% higher than that of plain surface, respectively. BY considering the balance of capillary effect and bubble convolution effect, a model of CHF is proposed to reveal the mechanism of optimum size of the micro pin fins. The predicted CHFs have an inaccuracy of less than ±20% comparing to experimental values. This paper makes up for the lack of basic experimental data on pool boiling of R1233zd(E) on aluminum surface, which thus provides guidance for

关键词： Heat flux

Characteristics and Prediction Model of Co-Pyrolysis of Sewage Sludge and Camellia Seed Shell

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SSRN 2022年

作者： Wang, Bo Liu, Yinhe Guan, Yu Feng, Yiwei Pan, Hejitian State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi’an710049 China

Tar is an undesired product in the process of sewage sludge pyrolysis, which affects the normal operation of the equipment. In this paper, the characteristics of co-pyrolysis of sewage sludge and camellia seed shell for tar reduction and syngas production were explored. The content and composition of tar and pyrolysis gas co-pyrolyzed with different proportions of sewage sludge (JAS) and camellia seed shell samples (CSS) were studied. The weight loss characteristics of the samples were studied by thermogravimetric experiment, and the synergistic effects of different stages were analyzed. The performances of back propagation (BP) neural network and particle swarm optimization-back propagation neural network (PSO-BP) in reflecting the nonlinear relationship between temperature, mixing ratio, heating rate and remaining weight were compared. The results show that the tar yield was the lowest when 40JAS60CSS was pyrolyzed, which could alleviate the serious problems caused by the tar. Compared with the JAS single pyrolysis, the co-pyrolysis of JAS and CSS improved the content of PAHs and reduced the content of aliphatic hydrocarbons in the tar. The inhibition and promotion effects of co-pyrolysis would be transformed into each other with the progress of the pyrolysis, and the transformations were concentrated in the S 2 stage where the weight loss of the sample is the largest. The constructed PSO-BP-30 model contained two hidden layers, each with 12 neurons, which accurately reflected the nonlinear relationship between the temperature, mixing ratio, heating rate and residual weight. © 2022, The Authors. All rights reserved.

关键词： Pyrolysis

Experimental Study of an Aluminum Based Three-Dimensional Thermosyphon Heat Sink with Microscale Enhancement Structure

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SSRN 2024年

作者： Yang, Xiaoping Bu, Shichao Jiang, Zhuye Zhou, Yao Sun, Zhen Zhang, Yonghai Wei, Jinjia School of Chemical Engineering and Technology Xi’an Jiaotong University Shaanxi Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China State Key Laboratory of Mobile Network and Mobile Multimedia Technology ZTE Corporation Hillsides China

Heat dissipation is a significant factor limiting the advancement of electronics. Currently, air cooling remains the most widely used method for heat dissipation due to the advantages of low-cost and easy-maintenance. However, the traditional air-cooling method based on all-solid heat sink fails to meet the fast development in thermal power of electronics because its limitation in area expansion by only solid fins. In this study, an aluminum based three-dimensional thermosyphon (3D-TS) coupling boiling-condensation heat transfer and forced air cooling is proposed to overcome the limitation of conventional air cooling methods. Meanwhile, micro pin-fins structure is used to enhance the boiling heat transfer as well as the performance of the 3D-TS. Using the environmentally friendly refrigerant R1233zd(E) as working fluid, the performance of the 3D-TS is experimentally studied and analyzed under different air volume flow rates. The results show that the total thermal resistance decreases firstly and then increases with the heating power, which is mainly dominated by the boiling mode on the substrate. Moreover, the micro pin-fins greatly enhances the boiling heat transfer on the substrate of the 3D-TS, which enables the 3D-TS to reach a minimum thermal resistance of 0.075 K/W and a maximum thermal dissipating power of 650 W with the temperature of the heating source below 85 °C. The 3D-TS proposed in this work is able to meet the cooling requirements of most high-performance chips. This paper provides valuable reference and guidance for the design and optimization of the phase-change devices. © 2024, The Authors. All rights reserved.

关键词： Aluminum

A study on free radical behaviors and reactions in supercritical water using quantum chemical simulation

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Journal of Molecular Liquids 2025年 419卷

作者： Ding, Weijing Takahashi, Osamu Wang, Junying Jin, Hui School of Transportation and Vehicle Engineering Shandong University of Technology Shandong Zi'bo255000 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an710049 China of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima739-8526 Japan

Supercritical water (SCW) gasification is one of clean and efficient utilization way of biomass, other organic matters or coal for hydrogen production, in which radical reactions studies in SCW are limited but crucial. Density-functional tight-binding (DFTB) molecular simulation is one of efficient and convenient approaches to investigate these microscopic processes. Therefore, free radical reactions in severe SCW environment were investigated via DFTB calculations in this work. The results showed that the order of the free radicals containing bond cleavages reacted in SCW environment was ·OH, ·CH, ·CH2, ·HO2, ·CH3 and ·C6H5 under the same conditions. The reaction processes of different radicals in SCW were obtained. ·H was the most active free radical of reactions. This work is expected to understand the properties of free radicals in SCW better and explore intrinsic reaction mechanisms, which may provide a theoretical support for accomplishing efficient and low-carbon complete SCW gasification for hydrogen production. © 2024 Elsevier B.V.

关键词： Free radical Gasification Hydrogen production Reaction Supercritical Water (SCW)

Preparation, improvement, and application of metal–organic framework-based sensing materials for gas leakage and emission: A review

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Nano Materials Science 2025年

作者： Liu, Manyi Wang, Liang Ren, Shan Bai, Bofeng Chai, Shouning He, Chi Zheng, Chunli Yin, Xitao Li, Fengguang College of Materials Science and Engineering Chongqing University Chongqing400044 China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an710049 China School of Physics and Optoelectronic Engineering Ludong University Yantai264000 China School of Materials Science and Engineering Hubei University of Automotive Technology Shiyan442002 China

Industrial gas leaks and flue gas emissions pose significant threats to the safety of industrial operations and the atmospheric ecological environment. Traditional gas sensing materials often struggle to meet the challenges posed by complex industrial environments. Recently, metal-organic framework (MOF)-based gas sensing materials have garnered significant attention in industrial gas detection due to their high sensitivity, selectivity, and tunable properties. The exponential increase in related publications highlights the growing research interest in this field. This paper presents a comprehensive review of the advantages of various types of metal-organic frameworks and their derivatives for detecting industrial gas leaks and flue gas emissions, alongside an introduction of representative MOF synthesis methods. Furthermore, the primary sensing mechanisms of MOF-based gas sensing materials and strategies for enhancing the sensing performance are summarized. The current state of MOF-based gas sensing materials in industrial gas detection is also discussed. Finally, the potential limitations, existing challenges, and future directions of MOF-based industrial gas sensing materials are systematically analyzed, with suggestions for addressing these challenges to advance industrial gas detection technologies. © 2025 Chongqing University

关键词： Application Improvement Industrial gas detection MOF-Based sensing materials Preparation