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Journal of Thermal Science 2022年第2期31卷 332-343页

作者： WANG Ye wu jingyi YANG Guang Institute of Refrigeration and Cryogenics Shanghai Jiao Tong UniversityShanghai 200240China

Porous media have been extensively used for the enhancement of heat transfer,due to their large specific surface *** many cases,the flow and heat transfer in porous media are also coupled with other flow patterns,such as the channel *** work investigates numerically a non-isothermal three-dimensional mixing process from a rectangular channel and a porous medium to reveal the influence of the structural parameters on the flow and heat transfer characteristics in the coupled *** detailed heat and momentum transport behavior at the coupled interface are analyzed at the *** of the friction factor and the Nusselt number within the porous media are proposed as functions of the Reynolds number,porosity,velocity ratio,and pore *** from the pore-scale simulations are also used to improve the less-cost representative-elementary-volume-scale numerical model,which can be further used for the modeling of relevant engineering problems.

关键词： porous media cross-flow pore-scale simulation structural effect convective heat transfer

Conduction-convection coupled heat transfer around a hollow cylinder under different buoyancy forces

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Chinese Journal of Aeronautics 2024年第4期37卷 216-228页

作者： Wanyu ZHANG jingyi wu Guang YANG Institute of Refrigeration and Cryogenics Shanghai Jiao Tong UniversityShanghai 200240China

In order to clarify the effect of a buoyancy force on conduction–convection coupled heat transfer in a hollow cylinder, the flow and thermal characteristics were analyzed using an RNG k-ε turbulence model. The Reynolds number was fixed at 1.014 × 10^(6), and the Rayleigh number varied from 1.122 × 10^(10)to 1.088 × 10^(11). Results have shown that, when considering the effect of an opposed buoyancy force, increasing the Rayleigh number has a positive impact on the rate of change and uniformity of the cylinder temperature. The temperature distributions along the axial and circumferential directions are similar for different Rayleigh numbers, but extreme values *** the axial direction, the maximum temperature is obtained at the interface between the variable-diameter part and the constant-diameter part. The maximum dimensionless temperature value decreases to 0.12 when the Rayleigh number increases to 1.088 × 10^(11). Along the circumferential direction, the temperature distribution is affected by the buoyancy force, which results in the temperature of the upper part being higher than that of the lower part. After nondimensionalization of the temperature and time, a correlation was proposed to illustrate the transient heat transfer process quantitatively. The standard deviation of the maximum relative temperature, representing the temperature uniformity, was also calculated. It was found that the difference in the direction of the buoyancy force made a huge difference. Compared with the opposed buoyancy force, the maximum dimensionless temperature is almost two times higher with an assisted buoyancy force. Similarly, the heat transfer coefficient with an assisted buoyancy force is half of that with an opposed buoyancy force. Overall, an assisted buoyancy force plays a negative role in terms of thermal characteristics. The flow field around the hollow cylinder was also illustrated to reveal the mechanism of the buoyancy force on magnitude and direction aspects

关键词： Buoyancy Conduction-convection heat transfer Transient analysis Hollow cylinder Non-dimensionalization

Vertically aligned two-dimensional materials-based thick electrodes for scalable energy storage systems

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Nano Research 2021年第10期14卷 3562-3575页

作者： Zhengyu Ju Xiao Zhang jingyi wu Guihua Yu Materials Science and Engineering Program Texas Materials InstituteThe University of Texas at AustinAustinTexas 78712USA

Together with the blooming of portable smart devices and electric vehicles in the last decade,electrochemical energy storage(EES)devices capable of high-energy and high-power storage are urgently ***-dimensional(2D)materials,benefiting from the short solid-state diffusion distance,are well recognized to possess excellent electrochemical ***,liquid diffusion,the rate-determining process in thick electrodes,is notably slow in 2D materials-based electrodes stemming from their stacking during electrode processing,which considerably limits their applications for high energy *** fully exploit intrinsic advantages of 2D materials for scalable energy storage devices,this review summarizes several important strategies,ranging from assembly to template methods,to fabricate vertically aligned 2D materials-based *** further discuss the advantages and challenges of these methods in terms of key features of thick electrodes and illustrate the design principles for high-energy/power devices.

关键词： two-dimensional materials energy storage alignment assembly high energy/power

Study on cyclic characteristics of the solar-powered adsorption cooling system

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Science China(Technological Sciences) 2009年第6期52卷 1551-1562页

作者： jingyi wu Sheng Li YanFei Hu Institute of Refrigeration and Cryogenics Shanghai Jiao Tong University Shanghai 200240 China

According to the typical variable heat source of solar energy and the unsteady adsorption process of adsorption chiller,the research of cyclic transient characteristics of the solar-powered adsorption cooling system is presented in this work.A mathematic model of the whole system including the model of adsorption chiller,which reveals the transient operation process of the solar-powered adsorption cooling system,is developed and verified by experimental *** the basis of the simulated results,the transient characteristics and the overall performance of the system,not only in the traditional open cycle mode but also in closed cycle mode,are both analyzed ***,the influence of parameters matching of components configuration and operation process on the cyclic characteristics of the system,such as the solar collector area,the water tank capacity and the chiller startup temperature,are *** research in this work may play a very important role in optimizing the system cyclic process and improving the system adaptability especially under the condition of variable heat source.

关键词： solar-powered cooling system adsorption chiller unsteady state cyclic characteristics

Sustainable nanostructured electrolyte additives for stable metal anodes

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eScience 2024年第4期4卷 54-68页

作者： Wenjie Fan Huanlei Wang jingyi wu School of Materials Science and Engineering Ocean University of ChinaQingdao 266404China

Metal anodes(e.g.,Li and Zn)are promising candidates for high-energy and high-power rechargeable ***,the commercialization of metal anodes is hampered by irregular dendrite growth,which severely deteriorates the safety and cyclability of metal *** the electrolyte by nanostructured additives to regulate the metal deposition shows great potential since the electrochemically nonreactive feature endows the regulation function with good *** this manuscript,the fundamental dendrite formation models and key parameters for stabilizing metal anode are first *** progress and functional mechanism of nanostructured additives for regulating the metal deposition are summarized in terms of regulatory model,i.e.,deposition-,adsorption-and ***,we also provide a detailed concluding outlook,pointing out the future trend of selecting new nanostructured additive candidates and elucidating synergistic effects and underlying mechanisms with the key attention being given to the assessments of practicality.

关键词： Metal anodes Electrolyte additives Sustainability Nanostructured materials

Research on the chemical adsorption precursor state of CaCl_2-NH_3 for adsorption refrigeration

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Science China(Technological Sciences) 2005年第1期48卷 70-82页

作者： WANG Liwei WANG Ruzhu wu jingyi WANG Kai Institute of Refrigeration and Cryogenics Shanghai Jiao Tong University Shanghai 200030 China Institute of Refrigeration and Cryogenics Shanghai Jiao Tong University Shanghai 200030 China Institute of Refrigeration and Cryogenics Shanghai Jiao Tong University Shanghai 200030 China Institute of Refrigeration and Cryogenics Shanghai Jiao Tong University Shanghai 200030 China

As a type of chemical adsorption working pair, the physical adsorption occurs first for CaCl2-NH3 because the effective reaction distance for van der Waals force is longer than that for chemical reaction force, and this physical adsorption state is named the precursor state of chemical adsorption. In order to get the different precursor states of CaCl2-NH3, the different distances between NH3 gas and Ca2+ are realized by the control of different phenomena of swelling and agglomeration in the process of adsorption. When the serious swelling exists while the agglomeration does not exist in the process of adsorption, experimental results show that the activated energy consumed by adsorption reaction increases for the reason of longer distance between Ca2+ and NH3, and at the same time the performance attenuation occurs in the repeated adsorption cycles. When the agglomeration occurs in the process of adsorption, the activated energy for the transition from precursor state to chemical adsorption decreases because the distance between NH3 gas and Ca2+ is shortened by the limited expansion space of adsorbent, and at the same time the performance attenuation does not occur. The adsorption refrigeration isobars are researched by the precursor state of chemical adsorption; results also show that the precursor state is a key factor for isobaric adsorption performance while the distribution of Ca2+ does not influence the permeation of NH3 gas in adsorbent.

关键词： refrigeration, chemical adsorption, precursor state of chemical adsorption, attenuation, activated energy.

Adsorption performances and refrigeration application of adsorption working pair of CaCl_2-NH_3

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Science China(Technological Sciences) 2004年第2期47卷 173-185页

The adsorption performance of CaCl2?NH3 is studied under the condition of different expansion spaces for adsorbent, and the relationships between adsorption performance of CaCl2?NH3 and the phenomena of swelling and agglomeration during adsorption are researched. It is found that the performance stability is related to the ratio of expansion space to the volume of adsorbent r as, and the performance attenuation is serious in the case of large r as. Severe adsorption hysteresis exists in the process of adsorption and desorption at the same evaporating and condensing temperatures, which is related to the stability constant of chemical reaction. This phenomenon cannot be explained by the theory of physical adsorption. Moderate agglomeration will be beneficial to the formation of ammoniate complex; the magnitude of expansion space will affect adsorption performance. Analysis shows that the activated energy needed in the process of adsorption for the sample with r as. of 2∶1 is less than that for the sample with r as of 3∶1. The refrigeration performance of CaCl2?NH3 is predicted from experiments. The cooling capacity of one adsorption cycle is about 945.4 kJ/kg for the adsorbent with an r as of 2∶1 at the evaporating temperature of 0°C. Keywords chemical adsorption - attenuation - adsorption hysteresis - ammonia - activated carbon - refrigeration

关键词： chemical adsorption, attenuation, adsorption hysteresis, ammonia, activated carbon, refrigeration.

A review on perfluoroalkyl acids studies:Environmental behaviors,toxic effects,and ecological and health risks

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Ecosystem Health and Sustainability 2019年第1期5卷 1-19,I0002页

作者： Wenxiu Liu jingyi wu Wei He Fuliu Xu MOE Laboratory for Earth Surface Processes College of Urban&Environmental SciencesPeking UniversityBeijingChina

Perfluoroalkyl acids(PFAAs)are emerging persistent organic pollutants that are globally distributed in the *** the present review,the occurrence of PFAAs and their behavior in aquatic ecosystem were summarized,and the health and ecological risk assessment and the multimedia fate simulation were *** are most likely to exist in the aqueous phase,and PFAAs in atmosphere are also able to enter water bodies through diffusion and wet and dry deposition and eventually become widely distributed in various environmental *** air-solid partition is considered to be one of the major factors in the long-distance transportation of the *** pKa values and organic carbon fraction of the sediment could influence the partition of PFAAs between water and ***,PFAAs have teratogenic,mutagenic and other toxic effects and they could be accumulated by biota,and magnified through trophic *** ecological and health risks of PFOA and PFOS were *** order to explore the partition mechanism and reduce the uncertainty of the simulation of the transport,transformation and fate,the experimental methods on physicochemical properties of PFAAs should be ***,further studies on toxicities of PFAAs are necessary for health and ecological risk assessment.

关键词： Perfluoroalkyl acids(PFAAs) distribution environmental behaviors risk assessment multimedia fate

Order-structuredsolid-stateelectrolytes

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SusMat 2022年第6期2卷 660-678页

作者： jingyi wu Zhixiang Rao Huanlei Wang Yunhui Huang School of Materials Science and Engineering Ocean University of ChinaQingdaoChina State Key Laboratory of Material Processing and Dieand Mold Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhanChina

Solid-state electrolytes(SSEs)are recognized as attractive candidates to real-ize safe and high-energy-density lithium metal batteries(LMBs).However,the practical application of SSEs still faces challenges such as insufficient room-temperature ionic conductivity,unsatisfactory mechanical properties,and large internal *** research efforts have been made to explore new electrochemistry and technologies to address those *** them,the construction of order-structured SSEs has emerged as a promising *** anisotropic behavior induced by the orientation offers SSEs with desired properties targeting specific functions,and therefore the rational design of the order-structured SSE provides an alternative solution to achieve an ideal *** review discusses the structure-property correlation of SSEs,and then sum-marizes the design strategies to construct order-structured ***,the current challenges and possible future research directions for order-structured SSEs for scalable high-energy-density LMBs are presented.

关键词： alignment ordered structure lithium batteries solid-state electrolytes

Study on Lithium Insertion in Lepidocrocite and ,λ-MnO2 Type TiO2： A First-Principles Prediction

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Chinese Journal of Chemistry 2013年第10期31卷 1257-1262页

作者： Yahui Liu jingyi wu Wei Zhao Jinglong Chu Tao Qi National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China Laboratory of Nuclear Analysis Techniques Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Molecular Nanostructure and Nanotechnology Beijing National Laboratoryfor Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China

TiO2 is a latent anode material for rechargeable lithium batteries. Our simulation models, basing lepidocrocite and 2-MnO2 type TiO2 were investigated by density functional theory （DFT）. The key issues are focused on the lithium insertion sites, electronic structures, and the conducting paths of Li＋ ions. Our calculated data indicate the calculated voltage of 2-MnO2 type TiO2 is higher than that of lepidocrocite type TiO2. The Li＋ ion migration energy barrier of lepidocroeite type YiO2 along the [1 0 0] direction （0.45 eV） is lower than that of along the [110] direction （0.57 eV）. The energy barriers of 2-MnO2 type TiO2 to move a Li＋ ion among the adjacent embedded sites （16c or 8a sites） is 0.68 eV.

关键词： titanium dioxide lithium insertion diffusion density functional theory transition state