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Clathrate Hydrate Framework Construction Enhanced by Waste Bio-Shavings for Efficient Methane Storage

ACS SUSTAINABLE CHEMISTRY & engineering 2022年第37期10卷 12127-12138页

作者： Yang, Liang Liu, Daoping Wang, Jiajie Liu, Ni Xie, Yingming Cui, Guomin Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China

Improving the hydrate formation rate as well as gas storage capacity is significant for gas hydrate technology applications. Porous woodshavings with different liquid-solid ratios (R-L/S) were prepared to capture methane in the form of hydrate. The kinetics of methane hydrate formation in wet shavings were studied using an unstirring reactor at pressures ranging from 5.0 to 8.0 MPa and a temperature of 274.2 K. The results demonstrated that the liquid water spread well on the surface of the shavings and permeated into their interior micropores. Wet multi-stack shaving beds could provide abundant channels for gas diffusing to the film water coated on the surface of the shavings. The rough and irregular wooden surface was capable of contributing a considerable number of nucleation sites for hydrate formation. The skeletons of wet shavings aided in the construction of a three-dimensional hydrate bridge and framework, which accelerated the upward migration of pore water and gravity water to form a hydrate crown. Compared with bulk water, the water dispersed by shavings greatly accelerated hydrate nucleation and growth. The R-L/S ceilings of wet samples that allowed for a significant quantity of methane hydrate formation were 11.0 (8.0 MPa), 9.0 (7.0 MPa), 8.0 (6.0 MPa), and 7.0 (5.0 MPa). The wet beds with the R-L/S of 8.0 exhibited the best gas storage performance at all pressures except 5.0 MPa. Furthermore, 10 cycles of repeated tests showed that wet shavings could store gas extremely stably, with cyclic peak gas uptakes ranging from 146.0 to 154.1 cm(3).cm(-3). A hypothesis of "hydrate shell-bridge-framework construction enhanced by bio-shavings" was proposed to illustrate the fast hydrate formation in the porous shavings.

关键词： methane storage clathrate hydrate formation kinetics waste bio-shavings enhancement

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Analysis of stability and internal flow mechanisms in spiral annular flow with different swirlers

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EXPERIMENTAL THERMAL AND FLUID SCIENCE 2024年 158卷

作者： Wang, Haoyu Yang, Yang Yang, Bin Tang, Yu Jing, Wenjie Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China

Spiral annular flow within ducts is widely utilized in modern industry, with the swirler serving as a critical component in generating such flow patterns. The structure of the swirler significantly influences the generation and stability of the spiral annular flow. This study selected four different swirler structures with outstanding performance from previous research and analyzed their characteristics through visual image processing combined with numerical simulations. By analyzing the amplitude information of the wave fluctuations in the annular swirling flow liquid film under different operating conditions using probability density functions, it was found that the swirler A(Flat-vane swirler) and swirler B(Flat-vane swirler with hub) produced smaller fluctuations in the annular swirling flow liquid film, indicating better stability compared to the swirler C(Arc-vane swirler) and swirler D(Spiral-vane swirler), which exhibited poor performance. Combining the numerical simulation results with the analysis of the internal mechanism of the swirlers, it was discovered that within the swirler A and swirler B, the fluid between the swirler vanes experienced a larger pressure gradient, resulting in phenomena such as "jump" and "pull" under this pressure gradient. This, in turn, contributed to the generation of greater tangential velocity and radial pressure gradient after the fluid exited the swirler. Due to the influence of the swirler structure, the swirler A and swirler B did not completely separate the fluid region into four independent spaces. Instead, in the central connection area of the rear section of the swirler, the gas phase components aggregated earlier, greatly promoting the downstream generation of spiral annular flow. This study analyzed the two-phase flow process and mechanism inside the swirler, filling a gap in previous research and providing important references for the optimization and selection of swirlers.

关键词： Gas-liquid two-phase flow Swirler Spiral annular flow flow characteristics Probability Density Function

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Experimental Investigation on Ejector Performance Using R134a as Refrigerant

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Journal of Thermal Science 2019年第4期28卷 727-735页

作者： DAI Zhengshu YU Bo LIU Pengpeng CHEN Guangming ZHANG Hua School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China State Key Laboratory of Air-conditioning Equipment and System Energy Conservation Zhuhai 519070China Institute of Refrigeration and Cryogenics Zhejiang UniversityHangzhou 310027China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai 200093China

Ejector refrigeration has the advantage of low capital cost,simple design,reliable operation,long lifespan and almost no *** only weakness is the low efficiency and its intolerance to deviations from design operation condition.R134 a used in ejector refrigeration system gives better performance in comparison with many other environmental friendly refrigerants as the generation temperature is from 75℃to 80℃.The present work experimentally investigated the on-design and off-design performance of the ejector with fixed geometry using R134 a as refrigerant,and cycle performance of the ejector refrigeration *** experimental prototype was constructed and the effects of primary flow inlet pressure,secondary flow inlet pressure and ejector back pressure on ejector performance and cycle performance were investigated *** operation conditions are:primary flow inlet pressure from 2.2 MPa to 3.25 MPa,secondary flow inlet pressure from 0.36 MPa to 0.51 MPa,ejector back pressure from 0.45 MPa to 0.67 *** were drawn from the experimental results,and the experimental data can be used for validation of theoretical model for both critical and subcritical mode.

关键词： ejector performance refrigeration R134a experiment

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Angle Scattering Method for Soot Concentration Measurement under Ultra-Low Emissions Condition

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Energy engineering 2022年第2期119卷 511-522页

作者： Bin Yang Xingchen Zhu Jie Deng Xiaoxu Guo Jinke Han Xiaowei Liu School of Energy and Power Engineering Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power EngineeringUniversity of Shanghai for Science and TechnologyShanghai200093China State Key Laboratory of Coal Combustion Huazhong University of Science and TechnologyWuhan430074China

Aiming at the problem of soot concentration measurement under ultra-low emission conditions,a forward small angle soot concentration measurement method is *** a typical boiler emission of 0.1μm-3.0μm bimodal distribution soot as an object,the particle scatter simulation calculation under different parameters is carried out,and the influence of detection angle and particle size on the angular scatteringmeasurement of ultra-low emission soot is *** influence of detection angle and particle size on the angular scatteringmeasurement of ultra-lowemission soot is ***,thewavelength of incident light is 650 nm,and the forward detection angle parameter is 15◦for the design of forward small angle soot concentration measurement *** experimental system for measuring soot with standard concentration is *** of particle concentration measurement of 1.0μm and 3.0μm under ultra-low emission conditions are carried *** results show that the average deviation of soot concentration measurement is less than 0.10 mg/m3 under the condition of ultra-low emission by using 15◦of forward detection,which provides an effective way for monitoring ultra-low emission soot concentration in coal-fired power plants.

关键词： Emission monitoring ultra-low emission soot concentration angular scattering

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Melting characteristics and dynamic evolution of microstructure of single-crystal gold film irradiated by laser under the non-Fourier effect

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MOLECULAR CRYSTALS AND LIQUID CRYSTALS 2021年第1期723卷 62-79页

作者： Wang, Qing Li, Ling Yang, Mo Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai Peoples R China

The process of ultra-thin single crystal gold film irradiated by femtosecond laser is simulated by the combination of improved two-temperature model (TTM) and molecular dynamics (MD). The results indicate that under the non-Fourier effect, the gold film shows special melting characteristics and spalling mechanism. The phenomena of homogeneous melting and pore spalling of gold film are successfully distinguished by curing rate method and atomic density method respectively. Due to the tiny thickness of the gold film studied, the damage mechanism of the gold film irradiated by laser has also changed.

关键词： Femtosecond laser melting characteristics metal film non-Fourier effect spalling damage

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Effect of flow-deflecting-gap blade on aerodynamic characteristic of vertical axis wind turbines

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RENEWABLE ENERGY 2020年 158卷 370-387页

作者： Zhu, Haitian Hao, Wenxing Li, Chun Ding, Qinwei Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai Peoples R China

In order to improve stall characteristics more effectively or eliminate dynamic stall in a revolution of vertical axis wind turbine, three kinds of novel flow-deflecting-gap (FDG) blade were designed and investigated numerically, including two-side FDG blade, toward-outside FDG blade and toward-inside FDG blade. Firstly, the aerodynamic characteristics of isolated flow-deflecting-gap blade were obtained and its effect was illustrated. Then, the investigation on aerodynamic characteristic of novel SB-VAWT was conducted. The obtained results indicated that compared to clean airfoil, FDG enhances the stalling angle of attack (AOA) by 2 degrees and increases lift-drag ratio at high AOA. Furthermore, FDG significantly decreases the frequency of vortex shedding and greatly reduces amplitude of lift oscillation. Fora vertical axis wind turbine, toward-inside FDG can efficiently decrease the optimal tip-speed ratio and improve the aerodynamic performance at low tip-speed ratio. Additionally, an increase of 10.21% of torque coefficient is caused by toward-inside FDG. Jet flow in FDG towards leading edge offsets the swirling flow over the suction surface and the trailing-edge vortex produced by bluff edge is also weakened or even eliminated by FDG. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Multi-element airfoil Gap Vertical axis wind turbine Aerodynamic characteristics Computational fluid dynamics

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Experimental investigation on thermal performance of a pumped two-phase battery cooling system using mini-channel cold plate

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INTERNATIONAL JOURNAL OF ENERGY RESEARCH 2021年第11期45卷 16078-16090页

作者： Xu, Dan Fang, Yidong Hu, Lingren Yang, Wenliang Su, Lin Univ Shanghai Sci & Technol Coll Energy & Power Engn Shanghai Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai Peoples R China

This study presents an experimental investigation on a pumped two-phase battery cooling system using R1233zd(E) as the refrigerant. The thermodynamic cycle of the system, together with the heat transfer and pressure drop characteristics of the mini-channel cold plate, were analyzed under different conditions. Results showed that the pressure rise of the pump was increased under higher heat flux and mass flux, and the overall system pressure was elevated when the coolant bath temperature was raised. The effects of the mass flux on the overall heat transfer coefficient of the cold plate were different under various heat fluxes, while pressure loss of the cold plate showed a dramatic rise after the heat flux was over 2 W center dot cm(-2). The average temperature of the cold plate was generally decreased with the increasing mass flux, while the maximum temperature difference was nearly constant when the heat transfer was dominated by single-phase forced convection. However, the maximum temperature difference could be lowered after flow boiling became dominant. In addition, the local heat transfer characteristics for different channels and the temperature uniformity in the cold plate were investigated. It was found that the local temperature was increased and then stabilized along the flow direction, while the local heat transfer coefficient was increased monotonously. Meanwhile, lower local temperature and higher heat transfer coefficient were found in the upper channel for the intensive boiling with lower mass flux which compared to the middle channel. Novelty Statement This study investigated the performance of a pumped two-phase battery cooling system using mini-channel plate under higher heat flux and discussed the reasons for wall temperature variation and temperature uniformity under different heat transfer mechanisms.

关键词： mini‐ channel pumped two‐ phase system temperature uniformity thermal performance

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Exergy Analysis of a Novel Chemical Looping Hydrogen Generation System Integrated with SOFC

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Journal of Thermal Science 2021年第1期30卷 313-323页

作者： ZHANG Xiaosong CHEN Zhewen CHEN Zhenbin LI Jinsong Mechanical and Electrical Engineering College Hainan UniversityHaikou 570228China Beijing Key Laboratory of Multiphase Flow and Heat Transfer North China Electric Power UniversityBeijing 102206China

In this paper,a novel system integrating chemical-looping hydrogen generation(CLH)system and solid oxide fuel cell(SOFC)has been *** new methane-fuelled energy system was investigated with energy balance and exergy *** produces the hydrogen as the fuel of the SOFC,and the Fe O and Fe3O4 are selected as the looping *** heat from the SOFC is absorbed by the CLH and converted to chemical energy through the reduction reaction of *** to the cascade utilization of the fuel between the CLH and SOFC,the net efficiency of this novel system can achieve 62.8%considering CO_(2)separation,more than 10 percentage points higher than a methane reforming fuelled SOFC ***,by using the CLH to produce the hydrogen,the CO_(2)can be recovered without an energy *** the analysis of the graphical exergy,the cascade utilization of waste heat and the high-efficiency hydrogen production is the main reason of high *** novel system also has the advantage of CO_(2)capture without energy penalty,so this combined system is an advantaged method to accomplish the efficient utilization of methane.

关键词： chemical looping fuel cell exergy analysis

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Experimental study of composition and influence factors on fouling of stainless steel and copper in seawater

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ANNALS OF NUCLEAR ENERGY 2016年 94卷 767-772页

作者： Yang, Dazhang Liu, Jianhua E, Xiaoxue Jiang, Linlin Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Peoples R China Key Lab Multiphase Flow & Heat Transfer Shanghai Shanghai Peoples R China

Metals and alloys are easily fouled in marine environment. It is a big problem for heat exchangers using cooling seawater in power plants or ships. In the paper, a seawater-fouling dynamic test device was built to investigate the composition and influence factors on fouling of stainless steel and copper in the cooling seawater system. Moreover, the static trials were performed to study the fouling and corrosion of stainless steel and copper in marine environment. The experimental results show that the seawater fouling of stainless steel is crystallization fouling, and the main elements of fouling are magnesium and aluminum. In addition, the results show that the seawater fouling of copper is corrosion fouling. In the dynamic experiments, the effects of heat flux and Reynolds number on stainless steel fouling were studied. The results show that higher heat flux and higher Reynolds number of seawater lead to the accumulation of seawater fouling. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Fouling Seawater Composition Influence factor Stainless steel Copper

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Experimental and on-site investigation of the in-line vertical axis water turbines for water pipelines

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JOURNAL OF RENEWABLE AND SUSTAINABLE ENERGY 2021年第3期13卷 1-9页

作者： Chen, Jian Wang, Miao Li, Chun Sun, Li Yang, Liang Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer 516 Jungong Rd Shanghai Peoples R China

Health monitoring devices are critical for the safe and reliable operation of water supply systems, but their chemical batteries are easily depleted. Thus, this paper developed a micro-vertical axis water turbine that converts part of the water head into electrical energy and supplies power for the monitoring device. The performance of four groups of micro-turbines was investigated in detail through experimental testing. Different from our previous study, the entire performance curves of micro-turbines at different rotation speeds and flow velocities were obtained in order to consider the wide range of flow velocities inside the real water pipeline. The feasibility of the designed turbines in the power supply system was verified by on-site testing. The experimental results show that different types and opening sizes of blocks have a distinct influence on the output power of micro-turbines. Each type of block has the corresponding optimal opening size to gain the highest performance. Within a certain range, the maximum output power varies linearly with the increase in flow velocity. In a specific flow velocity, the optimal rotational speed of the micro-turbine generated the maximum output power can be predicted by the power curve. In addition, through the experimental data, it is found that among all the measured turbines, the 12-blade hollow shaft turbine with a 90% eye-shaped block is the best one, with an output power of 88.2 W and an efficiency of 15.76%. Finally, the results of an on-site test are consistent with that of the experiment properly, which verifies the reliability of the measured data in the laboratory.

关键词： flow velocity

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