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NUMERICAL STUDY OF THE EFFECT OF PERIODIC WAKE ON FILM COOLING EFFECTIVENESS ON A PLATE

THERMAL SCIENCE 2025年第2A期29卷 1197-1206页

作者： Shi, Liuliu Fan, Haobo Chen, Eryun Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai Peoples R China

The research presented in this paper is devoted to exploring the influence of upstream periodic wake on the film cooling effectiveness on a downstream plate. This investigation is carried out through rigorous numerical simulations utilizing a dedicated simulation model. The model was developed to examine the impact of upstream periodic wake on film cooling performance across varying blowing ratios (M = 0.3, 0.5, and 1.0) and wake sweeping frequencies (10 Hz, 20 Hz, and 40 Hz). Comparative analyses are conducted with a baseline scenario involving a constant jet without wake. The objective of these analyses is to provide a deeper understanding of the mechanisms through which upstream wake influences film cooling performance, ultimately shedding light on the flow characteristics and cooling effectiveness of film cooling under sweeping wakes.

关键词： gas turbine film cooling wake blowing ratio

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On the spreading behavior of a droplet on a circular cylinder using the lattice Boltzmann method

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Chinese Physics B 2024年第6期33卷 434-443页

作者：杨帆金虎戴梦瑶 School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai 200093China

The study of a droplet spreading on a circular cylinder under gravity was carried out using the pseudo-potential lattice Boltzmann high-density ratios multiphase model with a non-ideal Peng–Robinson equation of state. The calculation results indicate that the motion of the droplet on the cylinder can be divided into three stages: spreading, sliding, and *** contact length and contact time of a droplet on a cylindrical surface can be affected by factors such as the wettability gradient of the cylindrical wall, the Bond number, and droplet size. Furthermore, phase diagrams showing the relationship between Bond number, cylinder wall wettability gradient, and contact time as well as maximum contact length for three different droplet sizes are given. A theoretical foundation for additional research into the heat and mass transfer process between the droplet and the cylinder can be established by comprehending the variable rules of maximum contact length and contact time.

关键词： lattice Boltzmann methods droplet circular cylinder wettability gradient

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The heat transfer enhancement mechanism for composite phase change material based on variable heating power and pore density

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JOURNAL OF ENERGY STORAGE 2025年 115卷

作者： Wang, Zilong Zhu, Hua Gui, Jintao Zhang, Hua Wu, Weidong Li, Ying Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Sch Mat & Chem Shanghai 200093 Peoples R China

Adding foam metal materials is one of the key methods to enhance the thermal conductivity of phase change materials (PCMs). To investigate the heat transfer mechanism of PCMs under different heat source powers and foam metal pore densities, a visualized thermal energy storage device was designed and constructed in this study. The effects of heat source power and the pore density of copper foam metal on the thermal properties of the composite PCMs, including internal temperature differences, equivalent thermal conductivity, comprehensive heat transfer coefficient, and heat storage performance during the melting process, were thoroughly analyzed. An empirical correlation for calculating the Nusselt number (Nu) of the composite PCMs was also derived. The research results indicate that the rate of temperature rise in the internal temperature difference of the composite PCMs increased with the rise in heat source power, while the melting time shortened accordingly. When the heat source power was increased from 30 W to 90 W, for composite PCMs with copper foam, the pore density of copper foam increased from 5PPI to 25PPI, and the rate of temperature rise in the internal temperature difference during the melting process enhanced from 176.9 % to 183.5 %, while the reduction in melting time enhanced from 61.9 % to 62.5 %. The comprehensive heat transfer coefficient of the composite PCMs is directly proportional to the heating power and inversely proportional to the pore density. When the heating power is increased from 30 W to 90 W, the comprehensive heat transfer coefficient of the composite PCM with a pore density of 5PPI is increased by 61 %, while that of 25PPI is increased by 59 %. Additionally, based on the structural parameters of copper foam metal, an empirical correlation for the Nu during the melting process of the composite PCM was derived, the error between the experimental value and the calculated value is +/- 5 %. In addition, the dimensionless heat-storage rat

关键词： Phase change material heating power Pore density Enhanced heat transfer Foam meta

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Development of a novel U-shaped decomposer for enhanced hydrogen production via HI decomposition in the sulfur-iodine cycle

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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2024年 91卷 893-900页

作者： Zhao, Muyang Ying, Zhi Yang, Aoli Fang, Zhongqiu Kong, Xiangyu Yu, Xiaosha Ye, Xiao Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China Pyneo Co Ltd Hangzhou 311000 Peoples R China

HI decomposition is the key step for hydrogen production in the thermochemical sulfur-iodine cycle. A HI decomposer with good performance usually has the characteristics of high HI decomposition rate, which is important for hydrogen production. Herein, a novel U-shaped decomposer was designed for HI decomposition. Thermodynamic calculations showed the negligible effect of pressure. The physical field modeling indicated that the U-shaped reactor exhibited the longer residence time and the lower pressure drop than the common straight reactor. The optimized experimental conditions for U-shaped reactor were experimentally and theoretically determined as the systematic weight hourly space velocity (WHSV) of 1000 h- 1, HI mass flow of 1.42 g/min, and catalyst mass of 85 mg. Subsequently, a series of activated carbon (AC) supported monometallic and bimetallic catalysts showed superior catalytic performance toward HI decomposition in our optimized U-shaped reactor than that in straight reactor. Especially the 1% Pt/AC and 0.5% Pt-0.5% Ir/AC exhibited excellent HI decomposition rate of 20.79% and 21.26%, respectively. Both of them performed excellent stability, which are promising candidates for HI decomposition in U-shaped decomposer. These findings provide new ideas and methods for improving the performance of the HI decomposition and thereby the development of sulfur-iodine cycle for hydrogen production.

关键词： Hydrogen production Sulfur-iodine cycle HI decomposition U-shaped decomposer Bimetallic catalyst

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Pore-scale study of coupled charge, gas, and liquid water transport in the catalyst layer of PEM fuel cells

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FUEL 2025年 380卷

作者： Dou, Shaojun Hao, Liang Wang, Yuanhui Wang, Qianqian Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China Yanshan Univ Sch Vehicle & Energy Qinhuangdao 066004 Peoples R China

Understanding the catalyst layer (CL) structure-process-performance relationship is essential for optimizing proton-exchange membrane fuel cells. This study stochastically reconstructs a high-resolution porous CL with a full thickness of 8 mu m. The liquid water distribution within CL is simulated by a capillary condensation model, and a pore-scale model coupling oxygen and proton transport with electrochemical reaction is developed to investigate the CL structure-performance relationship under different operating conditions. Results indicate that CL exhibits better performance at higher humidities, up to the flooding threshold at the water saturation of 0.41, as the benefits of increased electrochemical surface area, enhanced proton conductivity, and improved oxygen permeability through the ionomer film significantly outweigh the increased transport resistances through both the pores and the water film. Under the flooding condition at water saturation of 0.41, CL performance starts to decline due to the sharply increased pore resistance. Proper perforation of CL is suggested to alleviate the pore resistance in flooded electrodes. Additionally, reducing the Pt-to-C mass ratio is found to achieve better Pt dispersion in low Pt-loaded electrodes, thereby lowering the local oxygen resistance, and the bilayer CL design with higher Pt content on the membrane side is shown to further mitigate the performance degradation.

关键词： Polymer electrolyte membrane fuel cell Liquid water Pore-scale model Catalyst layer

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Experimental study on prediction model of wet gas pressure drop across single-orifice plate in horizontal pipes in the low gas phase Froude number region

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Chinese Journal of Chemical engineering 2022年第6期35卷 63-72页

作者： Youfang Ma Youfu Ma Junfu Lyu Weiye Liu Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power EngineeringUniversity of Shanghai for Science and TechnologyShanghai 200093China Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China

The pressure drop prediction of wet gas across single-orifice plate in horizontal pipes had been solved satisfactorily under an annular-mist flow in the upstream of orifice ***,this pressure drop prediction is still not clearly determined when the upstream is in an intermittent flow or stratified flow,which is corresponding to a region of low FrG(gas phase Froude number)in the flow pattern map of wet *** this study,the wet gas pressure drop across a single-orifice plate was experimentally investigated in the low FrG *** the experiment,the flow pattern transition in the downstream of single-orifice plates,as well as the effects of FrG and FrL(liquid phase Froude number)on UG(gas phase multiplier),were determined and compared when the upstream is in the flow pattern transition and the stratified flow region,*** performances were examined on the available pressure drop *** was found that no model could be capable of jointly predicting the wet gas pressure drop in the low FrG region with an acceptable *** a new method of correlating FrG and FrL simultaneously,new correlations were proposed for the low FrG *** which the modified Chisholm model shows the best prediction accuracies,with the prediction deviations of UG being within 7%and 3%when the upstream is in flow pattern transition and stratified flow region,respectively.

关键词： Gas-liquid flow Two-phase flow Wet gas Orifice plate Pressure drop Model

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Light transmittance measurement method of solid rocket motor plume based on laser modulation spectrum analysis

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PROPELLANTS EXPLOSIVES PYROTECHNICS 2024年第3期49卷 e202300224-e202300224页

作者： Yang, Bin Ye, Mingchun Qiang, Kejie Tao, Jinxin Chen, Sihua Chen, Jiahui Wang, Zhixin Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China Shanghai Space Prop Technol Res Inst Shanghai 201109 Peoples R China

The light transmittance measurement method, which is used to characterize smoke characteristic signal of solid rocket motor plume, can provide important reference for development and design of low smoke characteristic signal solid propellants and motors. The light transmittance measurement method of solid rocket motor plume based on laser modulation spectrum analysis is proposed in this paper. By using a 405 nm laser as the light source and a narrow-band filter detection method, the influence of plume radiation on the measurement of light transmittance of solid rocket motor plume smoke can be minimized. Additionally, combined with the laser modulation spectrum analysis technology, the signal amplitude is selected by the laser modulation frequency to improve the signal-to-noise ratio of the signal. Compared with the laser constant current measuring mode, laser high-frequency modulation measuring mode with spectrum analysis effectively improves the optical transmittance measurement accuracy. Based on this, a solid rocket motor plume smoke transmittance test system is developed to measure the plume smoke of standard test motors with different propellants and combustion chamber pressures. The results demonstrate that the system can effectively measure the light transmittance of the plume smoke. The light transmittance of solid rocket motor plume can be increased by reducing the aluminum content of solid propellant or increasing the pressure of the combustion chamber. Thus, this research provides an effective measuring tool for evaluating smoke concentration of solid rocket motor plume, which is beneficial to develop low smoke characteristic signal solid propellants and motors. image

关键词： laser modulation spectrum analysis technology light scattering attenuation method light transmittance plume smoke characteristic signal solid rocket motor

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Simulation of the dynamic behavior of droplet impact on the microstructure surface 1

Simulation of the dynamic behavior of droplet impact on the ...

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1st International Conference on Fluid Dynamics and Computational Science, FDCS 2022

作者： Yang, Jianhua Gao, Ming Sun, Hailin Liu, Zhennan Zhang, Kaiyuan Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power Engineering The University of Shanghai for Science and Technology Shanghai200093 China

The problem of droplets impacting rough wall has always been a hot spot in the engineering field. In this paper, the single-component multiphase lattice Boltzmann method is used to construct the wall microstructure, and the dynamic behavior characteristics of droplets impacting rough walls are simulated. The results show that the final state of a droplet impacting rectangular microstructure shows that the hydrophilic surface is more hydrophilic and the hydrophobic surface is more hydrophobic, and compared with the smooth surface, the microstructure surface hinders the rebound of the droplet, and the application of microstructure on the wall can promote the spreading of a droplet on the wall. © 2023 Institute of Physics Publishing. All rights reserved.

关键词： Drops

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Performance of vertical axis water turbine with eye-shaped baffle for pico hydropower

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Frontiers in Energy 2022年第4期16卷 683-696页

作者： Zhuohuan HU Dongcheng WANG Wei LU Jian CHEN Yuwen ZHANG Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power EngineeringUniversity of Shanghai for Science and TechnologyShanghai 20093China Department of Mechanical and Aerospace Engineering University of MissouriColumbiaMO 65211USA

t A series of inline pico hydropower systems,which could be used in confined space,especially for water distribution networks(WDNs),was designed and *** turbine with an eye-shaped vertical water baffle was developed to evaluate the hydraulic performance.A three-dimensional dynamic mesh was employed and the inlet velocity was considered as the inlet boundary condition,whereas the outlet boundary was set as the ***,numerical simulations were conducted and the standard k-εturbulence model was found to be the best capable of predicting flow features through the comparison with the experimental *** effects of the opening diameter of the water baffle and installation angle of the rotor on the flow field in the turbine were *** results suggested that the water baffle opening at d=30 mm and the rotor at a 52°angle could achieve the highest efficiency of 5.93%.The proper eye-shaped baffle not only accelerates the fluid flow and generates positive hydrodynamic torque,but also eliminates the flow *** scheme proposed in this paper can be exploited for practical applications in the water pipelines at various conditions and power requirements.

关键词： vertical axis water turbine eye-shaped vertical water baffle pico hydropower

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Synchronized measurement method of burning rate and combustion temperature of a solid propellant specimen

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APPLIED OPTICS 2024年第13期63卷 3420-3429页

作者： Ni, Hu Fan, Rong Hu, Haihang Yang, Bin Wang, Zhixin Cao, Di Yang, Yang Shi, Zhiquan Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China Shanghai Space Prop Technol Res Inst Shanghai 201109 Peoples R China

To characterize the combustion properties of solid propellants, the synchronized measurement method of burning rate and combustion temperature is proposed combined shadow imaging and radiation imaging. Using spectroscopic and filtering imaging, shadow and radiation images of a solid propellant specimen are obtained synchronously. Burning rate is calculated by burning surface movement velocity of shadow images, and combustion temperature is calculated by radiation image thermometry. Measurement accuracies of burning rate and combustion temperature of the solid propellant specimen are validated by other independent measurement methods. On this basis, the synchronized measurements of burning rate and combustion temperature of different formulations of solid propellant specimens under different working conditions are carried out. The results show that the influence on burning rate and combustion temperature of pressure and formulas is different. Therefore, the synchronized measurement of burning rate and combustion temperature can provide more direct data support for the evaluation of solid propellant combustion performance. (c) 2024 Optica Publishing Group

关键词： Absorption spectroscopy Bandpass filters Imaging systems Imaging techniques Numerical simulation Raman scattering

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