检索结果-内蒙古大学图书馆

Numerical investigation on the aerodynamic performance of vertical axis wind turbines utilizing a biomimetic fish tail paddle configuration

引用

ENERGY 2025年 323卷

作者： Ye, Zhou Yu, Hao Wu, Hong Li, Chun Wang, Ying 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

Inspired by natural phenomena, it has been observed that fish can freely maneuver their tails while swimming, allowing them to adjust their speed and direction with precision, thus controlling their swimming state. Drawing from this insight, a fishtail-like paddle structure was designed at the trailing edge of the vertical axis wind turbine wing. The extension length and deflection angle of the paddle were controlled at different azimuth angles through user-defined functions. Using computational fluid dynamics, the lift and drag coefficients, instantaneous torque coefficients, wind energy utilization coefficients, and flow fields of biomimetic fish tail structure airfoils and corresponding vertical axis wind turbines were analyzed. The research findings indicate that the blade can increase the surface pressure difference of the airfoil while simultaneously boosting torque, resulting in improved wind energy utilization coefficients for the vertical axis wind turbine across medium and low blade tip speed ratios (TSR). At a blade TSR of 2.63, with a deflection angle of 0 degrees and an extended horizontal length of 0.4c, the biomimetic fish tail vertical axis wind turbine employing active flow control exhibited optimal aerodynamic performance, with its maximum wind energy utilization coefficient increasing by 18.9 % compared to the reference vertical axis wind turbine. This study offers valuable insights into the efficiency in practical engineering scenarios.

关键词： Vertical axis wind turbine flow control Biomimetic fish tail Aerodynamic characteristics

来源：评论

学校读者我要写书评

暂无评论

Preparation and assessment of a novel hydrated salt PCM applied for intermittent floor radiant heating systems

引用

JOURNAL OF ENERGY STORAGE 2025年 105卷

作者： Liu, Jie Yang, Yingying Li, Aizheng Wang, Wensong Wu, Weidong 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

Intermittent floor radiant heating is widely employed in building heating systems. However, it suffers large indoor air temperature fluctuations due to its intermission. The integration of phase change material (PCM) can significantly mitigate this issue. In this study, Na2HPO4 & sdot;12H2O and Na2SO4 & sdot;10H2O were used as raw materials, with expanded perlite (EP) as the porous medium, to prepare a shaped composite phase change material (EPPCM). This material was then blended into mortar to produce a novel phase change mortar (EPPCM-M). Experiments were carried out to evaluate its heat storage performances. Compared to normal mortar, EPPCM-M of 25 mm thickness mitigates temperature fluctuations, with the peak temperature on the cold end reduced by about 2.5 degrees C and a slower cooling rate on the hot end. To assess the practical application of EPPCM in buildings, a simulation study was conducted. A room model of 4 x 4 x 3 m was built and subjected to radiant floor heating for 8 h daily, under the winter climate conditions of shanghai from November 15th to March 14th. The results showed that the EPPCM-M can effectively suppress temperature fluctuations in both the floor surface and average indoor air temperatures. From February 27th to March 5th, the maximum fluctuation of floor surface temperature was reduced by 55.4 %, the maximum fluctuation of average indoor air temperature was reduced by 39.5 %. The application of the EPPCM-M in intermittent floor radiant heating not only ensures indoor thermal comfort but also achieves heat's "peak load shifting", improving indoor comfort, reducing heating energy consumption, and promoting building energy efficiency.

关键词： Phase change material Thermal storage performance Intermittent floor radiant heating system Numerical simulation

来源：评论

学校读者我要写书评

暂无评论

Inhibition of methane hydrate generation with C60 studied by molecular dynamics simulation

引用

CHEMICAL engineering SCIENCE 2025年 306卷

作者： Liu, Ni Liu, Jiahao Li, Tanyu Huang, Jialei 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

Inhibition of hydrate generation is of great significance for methane storage and transportation. Fullerene C60 has unique chemical and physical properties and is expected to be a good hydrate inhibitor. In this study, the inhibition effect of C60 on the nucleation and growth of methane hydrates was analyzed by molecular dynamics simulations under NPT and NVE systems. The simulation results showed that C60 slowed down hydrate production and reduced the total number of cages and prolonged the induction time due to its own spherical structure, high-frequency rotation, poor thermal conductivity and aggregation at high temperatures. The results indicate that C60 can inhibit the hydrate production, and the inhibition effect increases with the rise of temperature and pressure. System with the addition of three C60s(2.7 wt%) showed the best inhibition effect.

关键词： Molecular dynamics simulation Methane hydrate Fullerene C60 Hydrate inhibitor

来源：评论

学校读者我要写书评

暂无评论

Research on the collapse process of a near-wall bubble

引用

Journal of Hydrodynamics 2023年第5期35卷 899-912页

作者： Bing Zhu Wang Han Wen-jun Xu Wei Zhang University of Shanghai for Science and Technology Shanghai200093China Shanghai Key Laboratory of Power Energy in Multiphase Flow and Heat Transfer Shanghai200093China Marine Design and Research Institute of China Shanghai200011China

The effect of wall on the bubble collapse is significant. A compressible numerical simulation method based on the state equation was used to numerically calculate the collapse process of bubbles at different leaving wall distances. The results show that when the dimensionless distance between the bubble center and the wall is greater than zero, the bubble generates a high-pressure region at the top of the interface, which induces a jet toward the wall. When the dimensionless distance is less than zero, the jet is generated from the vicinity of the contact position between the bubble and the wall and moves along the wall towards the center axis of the bubble. When the dimensionless distance is equal to zero, that is, the center of the bubble coincides with the center of the wall, the bubble shrinks uniformly, and its collapse process is consistent with that of a single bubble in free space under the same parameter conditions. Comparison of these three typical cases of dimensionless distance from the wall reveals that the presence of the wall induces an asymmetric effect and a pressure gradient effect in the flow field around the bubble, and the farthest point away from the center of the attached wall is a high-pressure region, which induces destabilization of the bubble interface and the occurrence of jets.

关键词： Bubble collapse compressible simulation shock wave propagation jet flow direction

来源：评论

学校读者我要写书评

暂无评论

An anti-greedy random walk algorithm for heat exchanger network synthesis

引用

CHEMICAL engineering RESEARCH & DESIGN 2024年 203卷 219-232页

作者： Huang, Xiaohuang Xu, Yue Xiao, Yuan Shan, Linghai Duan, Huanhuan Cui, Guomin Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China

heat exchanger network (HEN) synthesis is a vibrant research field in process system engineering, with substantial contributions to energy conservation and emissions reduction initiatives. The optimal design of a heat exchanger network is not an easy task due to the abundance of local optima in the solution space caused by the non-linear, non-convex, and discontinuous nature of the problem. Generally, several heuristic algorithms employ a greedy evolutionary mechanism, optimize through greedily accepting the decrease in the objective function, and converge to obtain the optimal solution. The Random Walk algorithm has a simple evolutionary mechanism, is prone to mutation, and exhibits high flexibility. However, the algorithm's inherent persistent greediness in searching restrict the scope of the search. Thus, this paper proposes an anti-greedy concept based on the Random Walk method to serve as the basis of a new synthesis approach called the Anti-greedy Random Walk algorithm. Two strategies are proposed in the algorithm, which broaden the solution domain by slowing down rapid unit reduction and accepting imperfect solutions, respectively. One strategy is to thoroughly search for the integer and continuous variables of the HEN problem by covering a much larger search space. Another is to escape the local extrema and move forward to discover more possibilities. Quantitative data demonstrates the algorithm's ability to avoid the local extrema and enhance the search effectiveness. Three different scales of classical cases are used in this work and the obtained results are superior to the published ones.

关键词： heat exchanger network synthesis Anti-Greedy Random Walk algorithm Anti-greedy selection strategy Regulation strategy Number of units

来源：评论

学校读者我要写书评

暂无评论

Particle analysis based on light extinction method illuminated by a divergent beam

引用

POWDER TECHNOLOGY 2024年 438卷

作者： Tian, Chang Xiao, Xinyu Su, Mingxu 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

A novel model based on the Monte Carlo principle was put forward to study the phenomenon of particle extinction spectrum under the condition of divergent incident beams and analyze the deviation during particle size inversion. Both the simulation results and experimental results show that the light extinction effect enhances obviously with the increase of divergence angle, accompanied by the distortion of extinction spectrum itself, which is closely related to particle size and optical wavelength. When the divergence angle is up to 20 degrees, the observed relative error during the retrieval of particle size can reach 12.8%, by comparing those obtained by the Lamber-Beer law for particle to the nominal diameter of 0.8 mu m. Accordingly, an improved inversion technique was studied, which yielded the particle size measurement error below2% for particles of 0.2 mu m, 0.8 mu m and 2.88 mu m in nominal size.

关键词： Light extinction spectrum Monte Carlo method Particle size measurement Divergent beam Error correction

来源：评论

学校读者我要写书评

暂无评论

REV-Scale study of miscible density-driven convection in porous media

引用

COMPUTERS & FLUIDS 2024年 281卷

作者： Meng, You Wang, Yifan Sun, Zhenghao Wang, Haoyu Chen, Yujun Liu, Gaojie 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

Miscible density-driven convection in porous media has important implications for the long-term security of geological CO2 2 sequestration. In this study, a REV-scale lattice Boltzmann equation method based on the generalized Navier-Stokes equations was used to simulate density-driven convection in porous media, Thus, the effects of the Rayleigh number, the Darcy number, the Schmidt number, and the porosity of porous media can be discussed separately. The results show that density-driven convection only occurs when the Rayleigh- Darcy-Schmidt number Ra D-S exceeds 102. 2 . The larger the Ra, the more disordered the concentration field, the earlier the convective phenomenon begins, and the more significant the convective mixing;The larger the Da, the finer the generated fingers. These findings provide important insights for the development of geological sequestration technologies.

关键词： Miscible density-driven instability Representative elementary volume (REV) scale Lattice Boltzmann method

来源：评论

学校读者我要写书评

暂无评论

Experimental investigation on frosting performance of a microchannel heat exchanger in heat pump system for electric vehicles

引用

APPLIED THERMAL engineering 2024年 249卷

作者： Liu, Ni Li, Dongming He, Jianfeng Li, Kang Tian, Yafen 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

Frosting of outdoor heat exchangers deteriorates the heat transfer performance of the electric vehicle (EV) heat pump system. The frosting performance of the outdoor heat exchanger in an EV heat pump air-conditioning system was investigated experimentally, considering different flow configurations, tube arrangements, and frontal air volume. The purpose of the study was to establish the optimal tube arrangements and flow configurations for minimizing frost formation and maximizing system performance. The results indicate that a three-flow configuration outperforms a two-flow setup under frosting conditions. Specifically, a flow sequence of 14-21-35 increases the heat capacity by 15.05 %-20.64 % compared to that of the reverse flow of 35-21-14. Additionally, the coefficient of performance (COP) increases by 1.19 %-3.55 %. Higher airflow reduces frost formation. A significant correlation exists between the refrigerant distribution within the heat exchanger and the corresponding frost distribution on the surface of the microchannel heat exchanger. The frost formation rate was slower for the flat tube vertical arrangement. Furthermore, horizontal tube arrangements were more conductive than vertical ones, providing a more uniform temperature distribution and higher heat transfer rates (an increase of 2.7% in heat transfer and 3.4% in heat capacity). The COP of the vertical arrangement system was consistently higher than that of the horizontal arrangement by 1.4 %-3 %.

关键词： heat pump air-conditioning system Microchannel heat exchanger Tube arrangement Frosting characteristic Temperature uniformity coefficient

来源：评论

学校读者我要写书评

暂无评论

Investigation on the flow characteristics through different discharge port in scroll compressor for electric vehicles

引用

INTERNATIONAL JOURNAL OF REFRIGERATION 2024年 168卷 135-148页

作者： Tian, Yafen Liu, Zhixiang Xia, Yang Jiang, Ziqi Li, Kang Liu, Ni 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

Scroll compressor with short scroll profile length shows great potential in electric vehicles for its compact structure and better reliability, while shorter scroll profile results in less compression time and undercompression in most cases. To investigate the influence of discharge port structure on compressor performance, a three-dimensional transient model of scroll compressor for electric vehicle is established. The theoretical and experimental results exhibit good consistency within a deviation of 9.5 %. With this validated model, the effects of discharge port size and shape on compressor performance are studied respectively. When the circular discharge port diameter increases from 5.2 mm to 9.0 mm, the power consumption and discharge temperature can be reduced respectively by 5.82 % and 5.29 %. The discharge mass flow rate can be promoted by 1.09 %. The discharge pressure fluctuation and imbalance between the upside and downside chambers enhanced obviously. To further improve the discharge flow characteristics, different discharge port shapes were employed including waist-shaped, arc-shaped and composite-shaped port. Compared with 5.2 mm circular port, the power consumption with composite-shaped port reduces by 5.81 % and mass flow grows by 1.26 %. Results indicated changes in discharge port structure parameters have greater influence on power consumption rather than mass flow rate.

关键词： Electric vehicle Scroll compressor Discharge port Numerical simulation Performance

来源：评论

学校读者我要写书评

暂无评论

Experimental investigation on the gravity driven discharge of cohesive particles from a silo with two outlets

引用

Particuology 2024年第6期89卷 11-21页

作者： Li Dai Zhulin Yuan Fengxian Fan Conghui Gu School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing 210096China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China School of Energy and Power Jiangsu University of Science and TechnologyZhenjiang 212100China

An experimental study on the gravity driven discharge of cohesive particles from a silo with two outlets was *** discharge behaviors under the conditions that a single outlet was open and two outlets were open were investigated by varying the moisture content of the particles and the filling height of the particles in the *** results show that the discharge rate of the cohesive particles increases gradually at the beginning,then almost keeps constant,and finally drops *** discharge rate in case of two openings is around 1.1–1.6 times that in case of a single *** filling height leads to lower discharge rate in case of a single opening but results in higher discharge rate in case of two ***,the avalanche dynamics in case of a single opening was examined,and the mixing behavior of the cohesive particles was *** is observed that the discharge flow is promoted by the avalanche phenomenon in the silo,generating a general trend that the normalized mass of discharge increases with the filling height at higher moisture *** case of a single opening,the transition from mass flow to funnel flow favors the particle mixing,resulting in an increasing mixing index as the moisture content *** general,a better performance of mixing can be achieved in case of a single opening compared with in case of two *** study provides vital information for fundamental understanding of the gravity driven discharge of cohesive particles from the silo with multiple outlets.

关键词： Cohesive particles Moisture content Discharge rate Avalanche Mixing

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：