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EFFECTS OF FLUID-SOLID WALL heat transfer ON THE ACHIEVABLE SIMULATED SOLID WALL CONTACT ANGLES IN PSEUDOPOTENTIAL LATTICE BOLTZMANN METHOD WITH DIFFERENT GHOST FLUID LAYERS CONSTRUCTED AT A SOLID WALL

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heat transfer RESEARCH 2022年第8期53卷 21-33页

作者： Wang, Dongmin Univ Shanghai Sci & Technol Sch Energy & Power Engn Key Lab Multiphase Flow & Heat Transfer Shanghai Shanghai 200093 Peoples R China Suzhou Univ Sci & Technol Jiangsu Key Lab Micro & Nano Heat Fluid Flow Tech Suzhou 215009 Peoples R China

In the pseudopotential multiphase lattice Boltzmann method, a ghost fluid layer is often constructed at a solid wall to simulate wall wettability under isothermal conditions. But the effects of fluid-solidwall heat transfer on the achievable simulated heating solid wall contact angle remain unclear, with different types of ghost fluid layer constructed at the solid wall. A two-dimensional semicircular liquid droplet on a heating solid wall evolving to the equilibrium contact angle has been simulated by the pseudopotential multiphase lattice Boltzmann method. It is found that with the ghost fluid layer constructed by the duplicated method, the fluid-solid wall heat transfer leads to droplet shape distortion and drastic increase of spurious velocity at any fluid-solid interaction strength G(s), resulting in the algorithm collapse and a failure in implementing any heating solid wall contact angles. With the ghost fluid layer constructed by constant fluid density, the fluid-solid wall heat transfer leads to solid wall contact angle slightly increasing and narrowing down the achievable simulated solid wall contact angle to the range from 103 degrees to 155 degrees. With the ghost fluid layer constructed by local fluid density, the fluid-solid wall heat transfer leads to the heating solid wall contact angle largely decreasing and narrowing down the achievable simulated heating solid wall contact angle to the range from 14 degrees to 25 degrees.

关键词： contact angle ghost fluid layer heat transfer pseudopotential multiphase lattice Boltzmann method

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Life Cycle Assessment Analysis and Comparison of 1000 MW S-CO_(2)Coal Fired power Plant and 1000 MW USC Water-Steam Coal-Fired power Plant

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Journal of Thermal Science 2022年第2期31卷 463-484页

作者： LI Mingjia WANG Ge XU Jinliang NI Jingwei SUN Enhui Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy&Power EngineeringXi’an Jiaotong UniversityXi’an 710049China Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power UniversityBeijing 102206China

The objective of this paper is to understand the benefits that one can achieve for large-scale supercritical CO_(2)(S-CO_(2))coal-fired power *** aspects of energy environment and economy of 1000 MW S-CO_(2)coal-fired power generation system and 1000 MW ultra-supercritical(USC)water-steam Rankine cycle coal-fired power generation system are analyzed and compared at the similar main vapor parameters,by adopting the neural network genetic algorithm and life cycle assessment(LCA)***-objective optimization of the 1000 MW S-CO_(2)coal-fired power generation system is further carried *** power generation efficiency,environmental impact load,and investment recovery period are adopted as the objective *** main vapor parameters of temperature and pressure are set as the decision *** results are concluded as ***,the total energy consumption of the S-CO_(2)coal-fired power generation system is 10.48 MJ/k Wh and the energy payback ratio is 34.37%.The performance is superior to the USC coal-fired power generation ***,the resource depletion index of the S-CO_(2)coal-fired power generation system is 4.38μPRchina,90,which is lower than that of the USC coal-fired power generation system,and the resource consumption is ***,the environmental impact load of the S-CO_(2)coal-fired power generation system is 0.742 m PEchina,90,which is less than that of the USC coal-fired power generation system,0.783 m PEchina,*** all environmental impact types,human toxicity potential HTP and global warming potential GWP account for the most environmental ***,the investment cost of the S-CO_(2)coal-fired power generation system is generally less than that of the USC coal-fired power generation system because the cost of the S-CO_(2)turbine is only half of the cost of the steam *** optimal turbine inlet temperature T_(5)becomes smaller,and the optimal turbine inlet pressure is unchanged at 622.082°C/30 MPa.

关键词： S-CO_(2)power plant ultra-supercritical water-steam Rankine cycle power plant life cycle assessment energy efficiency environment impact economic performance

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Lanthanide-Functionalized Carbon Quantum Dot-Based Dual-Emission Hydrogels for Multilevel Anti-counterfeiting and Repeatable Information Loading

ACS APPLIED OPTICAL MATERIALS

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ACS APPLIED OPTICAL MATERIALS 2024年第5期2卷 714-724页

作者： Li, Ying Xu, Chen Wang, Zi-Long Lu, Jia-Zhen Shang, Yi-Chen Wang, Mi-Tang Univ Shanghai Sci & Technol Sch Mat & Chem Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China

With the increasing development of advanced optical anti-counterfeiting technologies, it is essential to develop a simple, fast fluorescent material with anti-counterfeiting properties. In this study, we successfully prepared a single-emission CDs-based hydrogel (CDs@PVA-Alg) by introducing carbon dots (CDs) into the interpenetrating network of sodium alginate (Alg) and poly(vinyl alcohol) (PVA) via hydrogen bonding and further cross-linking them with Ln3+ ions to obtain dual-emission Ln-functionalized CDs-based hydrogels (Ln@CDs@PVA-Alg) (Ln = Tb, Eu). By freeze-thawing and ion-exchange methods, the resulting hydrogels displayed extraordinary mechanical properties and significant photoluminescent properties. On one hand, the CDs@PVA-Alg hydrogel demonstrated distinct fluorescence responses to Ln3+ ions. On the other hand, the fluorescence of Tb@CDs@PVA-Alg was quenched by H+ ions and restored in OH- solution. Furthermore, the mechanism of the above fluorescence response was explored in depth, which was further used to create an excellent optical anti-counterfeiting platform that can be utilized for multilevel anti-counterfeiting and repeatable information loading. By changing the excited light and chemical reagent, these materials enable versatile operations such as encryption, decryption, decoding, loading, and unloading of a wide range of information. This study not only supplies a representative example of the fabrication of dual-emitting Ln@CDs@PVA-Alg hydrogels but also investigates their potential application as smart polymeric gels with multifunctionality.

关键词： carbon quantum dots hydrogel films fluorescencesensing mechanical toughness anti-counterfeiting

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Dynamic analysis of rolling ball bearing-rotor based on a new improved model

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SN APPLIED SCIENCES 2022年第6期4卷 1-12页

作者： Nan, Guofang Jiang, Shan Yu, Dengliang Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China

Dynamic analysis for a bearing-rotor system with the imbalance and the asymmetric gap is conducted in this paper. A new improved analytical model overall considering the gap, the varying compliance vibration and the time-dependent unbalanced force is established, especially the new model is more accurate and closer to reality by abandoning the assumption of the traditional model that the three center points of the inner ring, the outer ring and the rolling ball are collinear. More general vibration characteristics are described and the calculation results based on the new model are more universal than those based on the traditional model. The comparison of the calculation result between the improved model and the traditional model shows that the phase difference for the two results is obviously different from each other, the dominant frequency has no obvious difference between the two models and the amplitudes have somewhat difference. The parametric excitation vibration induced by the varying compliance force of the rolling ball on the inner ring-rotor is analyzed and then the influences of the rotating speed, the gap, the eccentricity and the mass of the rotor on the nonlinear responses are studied and some important conclusions are drawn. As the speed increases, the VC frequency gradually loses its domination of the frequency spectrum, and the rotational speed frequency and its combined frequency with the VC frequency dominate the vibration. The bearing-rotor system is susceptible to the variations of the rotational speed, the gap, the eccentricity and the mass of the rotor in certain ranges;the parameters can make the system in a relatively stable, stable and unstable state;the system shows the complex dynamic behaviors such as the periodical vibration, the quasi-periodic vibration, the chaotic motion and the jumping phenomenon, the bifurcation, sudden change. The research is significant for the quantitative calculation of the dynamic response for parameter desi

关键词： Bearings Gap Improved model Nonlinear Varying compliance

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Unsteady wall effects on hydrodynamics and energy absorption in a flexible traveling wave plate: Roles of dimensionless wall distance and wave speed

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Renewable Energy 2025年 252卷

作者： Cui, Zhifei Bai, Yang Cao, Peiyu Huang, Diangui University of Shanghai for Science and Technology Shanghai200093 China Shanghai Key Laboratory of Power Energy in Multiphase Flow and Heat Transfer Shanghai200093 China

This study investigates the hydrodynamic and energy absorption characteristics of a two-dimensional flexible traveling wave plate in energy absorption mode, focusing on the impact of unsteady wall effects and their interaction with the wake vortex structure. Numerical simulations reveal that the wall effect significantly alters both the time-averaged and instantaneous force coefficients, with variations depending on the dimensionless wave speed(C) and wall distance(D). Specifically, the time-averaged transverse force coefficient decreases by 45.9 % at D = 0.2 and C = 0.4 compared to unbounded conditions, while the longitudinal force coefficient exhibits a complex trend, transitioning from a monotonic decrease to a decrease followed by an increase, influenced by wave speed. The wall effect also disrupts the symmetry of the instantaneous force coefficients, complicating the force curves. Furthermore, the wall increases the average differential pressure power, slightly enhancing energy absorption efficiency at D = 0.8–1.0, but reducing efficiency at D = 0.2–0.7. The wall also disturbs the wake vortex structure, causing premature dissipation of the positive vortex core and weakening energy harvesting near the wall. These findings highlight the wall's complex influence on hydrodynamic performance and energy absorption, offering insights for energy-harvesting device design near the wall. © 2025 Elsevier Ltd

关键词： Light absorption

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Enhanced electronic cooling with guest NCG microbubbles

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APPLIED THERMAL engineering 2025年 272卷

作者： Luo, Peng Tong, Wei Wei, Lichuan Zhang, Jie Zhao, Yugang Zhang, Hua Cheng, Ping Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China Shenzhen Envicool Technol Co Ltd Shenzhen 518129 Peoples R China China Aerodynam Res & Dev Ctr Key Lab Icing & Anti Deicing Mianyang 621000 Sichuan Peoples R China Shanghai Jiao Tong Univ Sch Mech Engn Key Lab Power Machinery & Engn MOE Shanghai 200240 Peoples R China

Electrical and electronic devices are producing a higher density of heat along with their elevated performance to meet the booming needs of industrials and human activities, and in response, more effective cooling technologies are always in demand. Liquid immersion is one of the most popular cooling methods developed due to its thermal efficiency and operational feasibility. However, conventional single-phase immersion cooling exhibits relatively lower thermal efficiency and heat capacity, and dual-phase immersion cooling occurs only when the heating surface temperature exceeds the liquid boiling point, constraining the selection of suitable coolants. This work presents a cooling method using guest noncondensable gas (NCG) microbubbles to enhance heat transfer in immersion cooling. Direct experimental results show that the heat transfer rate increases drastically, and surface superheating is suppressed or even eliminated. NCG microbubbles can disturb the thermal boundary layer, serve as evaporation/boiling nuclei, and collide with existing bubbles to facilitate their departure. This cooling method performs better at a large degree of pool subcooling, while the effect of bubble size is relatively minor. The fundamental understanding of bubble dynamics upon impinging onto the heating surface in subcooled liquid has promising applications in thermal management systems, such as microelectronic chips, nuclear reactors, steam generators, and among others.

关键词： Noncondensable gas Microbubbles Immersion cooling heat transfer enhancement

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Experimental study of electronic expansion valve opening on the performance of electric vehicle heat pump system at different compressor speeds

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INTERNATIONAL JOURNAL OF REFRIGERATION 2023年 149卷 94-104页

作者： Wang, Fengxian Wu, Weidong Zhu, Qundong Li, Kun Zhang, Hua Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Inst Refrigerat & Cryogen Engn 516 Jungong Rd Shanghai 200093 Peoples R China

The good matching of the electronic expansion valve (EXV) opening and compressor speed in an electric vehicle heat pump air conditioning system is significant for improving the whole system performance. The matching of EXV opening and compressor speed and its effect on system performance was experimentally investigated and analyzed. The results showed that at various compressor speeds, the condensing pressure increased and the evaporating pressure decreased to a small extent with the decrease of EXV opening, thus increasing the pressure ratio. The condensing pressure had a jump phenomenon at a specific EXV opening, and the corresponding jump opening was different at each compressor speed. The COP reached the optimal values of 2.4, 2.6, and 2.1 at the EXV opening of 110, 100, 90 steps, respectively, due to the synergistic effect between compressor speed and EXV opening. Moreover, it was found that the changing trend of COP was consistent with that of condenser outlet temperature. The compressor speed and EXV opening had a more significant impact on condensing pressure than evaporating pressure. The influence of compressor speed on each performance parameter was greater than that of EXV opening, while the EXV opening significantly influenced the subcooling degree. Under different compressor speed conditions, changing the single adjustment step of EXV according to the influence of EXV on each parameter can realize the rapid and accurate control of the heat pump system performance, which can provide a reference for the formulation of relevant control strategies and the reduction of the system energy consumption.

关键词： heat pump Electric vehicle EXV opening Compressor speed Control strategies

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Experimental and Modeling of NOx Removal in Water under High Pressure Relevant to CO2 Compression and Purification Process

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INDUSTRIAL & engineering CHEMISTRY RESEARCH 2022年第41期61卷 15433-15446页

作者： Wang, Zhen Liu, Dunyu Chen, Jun Jin, Jing Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China

Acid gas compression and purification are an effective way for the treatment of NOx in oxy-fuel combustion flue gas due to the reduced volume flow rate of flue gas in oxy-fuel combustion in comparison with air combustion. The design of reactors for NOx removal is particularly important for future CO2 utilization and storage and is also rather challenging due to the impact of pressure on both kinetic as well as mass-transfer parameters. To obtain the sensitivity as well as pressure dependence of different parameters, NOx removal in water under high pressure in both bubbling and film modes was investigated based on both experimental and modeling methods. Six uncertain parameters, including mass-transfer coefficients of NO and NO2 (kNO and kNO2), NO oxidation rate constant k1, liquid surface area S1, liquid film surface area S2, and liquid film volume VL, were identified and optimized to minimize relative errors between measurements and simulations. Three most important parameters affecting the simulated NOx absorption results are kNO2, k1, and S1, followed by kNO. While S2 and VL only affect NO2, these two parameters have little effect on NO, HNO3, and HNO2. In the gas bubbling reactor system, the liquid phase plays the main absorption role in NOx and the liquid film plays a supplementary absorption role. The effective removal of NOx in the high-pressure system can also be achieved by using only liquid film absorption rather than gas bubbling absorption as gas absorption by the liquid film can generate high concentrations of HNO3, which is beneficial for subsequent utilization.

关键词： Absorption Bubbles Gases Liquids Oxidation

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Numerical simulation study of indoor disinfection spray distribution based on CFD-DPM method

JOURNAL OF ENGINEERING RESEARCH

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JOURNAL OF engineering RESEARCH 2024年第3期12卷 562-570页

作者： Lu, Ye Li, Shen Xu, Wen Wang, Ying Dept Environm Hlth Zhejiang Prov Centerfor Dis Control & Prevent Hangzhou 310051 Peoples R China Sunlumos Disinfectant Shanghai Co Ltd Shanghai 202155 Peoples R China Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China

In today's world, environmental safety has become a top priority, with a special focus on terminal disinfection of indoor environments, which has proven to be a crucial and formidable issue in infection control. The use of hydrogen peroxide disinfection through vaporization or atomization presents a viable solution to the challenges posed by traditional wiping disinfection and ultraviolet disinfection methods that are plagued by incomplete disinfection and other factors that can significantly reduce the virus content within a room. To improve the application of hydrogen peroxide disinfection spray, the CFD-DPM (Computational Fluid Dynamics-Discrete Particle Model) method is employed to simulate the particle distribution of traditional sprays in a 30 m3 room. The study places emphasis on analyzing the impact of the placement position and bottle number of disinfection spray on the distribution of spray particles. The results demonstrate an impressive consistency between the numerical simulation method and experimental findings regarding the particle size distribution of disinfectant spray across various Schemes, validating the method's accuracy and reliability. However, the placement of a single disinfection spray source is insufficient to achieve uniformly distributed particles throughout the space when a bathroom is present within a given room. Nevertheless, by placing internal and external sources within the bathroom, the distribution of disinfectant spray particles becomes more even, thanks to a well conceived placement technique and an increased number of spray sources. Among all the schemes tested, Scheme 4 stands out for its ability to produce the greatest number of spray particles, with almost 60.71% of these particles remaining airborne for over 40 s. Therefore, it is also the most effective scheme for conducting disinfection.

关键词： Hydrogen peroxide disinfection spray DPM Particle existence time Disinfection

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The influences of the oil circulation ratio on the performance of a vapor injection scroll compressor in heat pump air conditioning system intended for electrical vehicles

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INTERNATIONAL JOURNAL OF REFRIGERATION 2023年 151卷 208-218页

作者： Li, Kang Ma, Jingru Cao, Jian Zhang, Bin Dou, Binlin Liu, Ni Zhang, Hua Su, Lin Zhou, Xuejin Tu, Ran Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Key Lab Multiphase Flow & Heat Transfer Shanghai P Shanghai 200093 Peoples R China Huaqiao Univ Coll Mech Engn & Automat Xiamen 361021 Fujian Peoples R China

heat pump air conditioning (AC) based on a vapor injection scroll compressor has proven to be a promising solution to the current driving range limitations of electric vehicles (EV), especially in freezing climates. The lubricating oil inside the compressor is critical in promoting sealing and cooling, but it also exhibits a low performance under extreme working conditions. In addition, the effects of oil retention on compressor behavior and the optimal charge amount at low temperatures require further investigation. This paper adapts a second refrigerant calorimeter method to study the effects of different injection pressures on compressor performance. The results indicate that the mass flow rate, discharge temperature, compressor power consumption, and volume efficiency performance would increase significantly compared with the non-vapor injection (NV). The effects of oil circulation rate (OCR) on the performance of a vapor injection scroll compressor under two low-temperature operating conditions were also studied. The flow and heat transfer parameters were analyzed, and heating capacity was found to increase and decrease with enlarged OCR. The highest coefficient of heating performance (COP) was obtained at an OCR of 3.5% with a vapor injection pressure of 0.28 MPa. Compared with the nonvapor injection (NV) condition, the heating capacity and COP of the system at the same pressure of 0.28 MPa were increased by 6.2% and 1.8%, respectively. At extremely low temperatures, the heating capacity and COP were maximized at an OCR of 5.5% and an injection pressure of 0.45 MPa. Compared with that of NV, the heating capacity and COP of the heating system at the injection pressure were increased by 6.7% and 2.6%, respectively. The compressor discharge temperature decreased obviously with the increasing OCR. An empirical formula was devised to calculate the heating capacity for varying OCR.

关键词： Oil circulation rate Vapor injection Electric scroll compressor Compressor performance heating capacity

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