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学者姓名：唐桂华
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Abstract ：
A liquid rocket engine needs to be protected against damage of the combustion chamber wall during operation, being exposed to high temperature and pressure gas conditions. It is in urge to design a simple and efficient thermal protection method to cool the wall of the thrust chamber. In present study, a liquid rocket engine CFD model with cooling holes in the upstream side of the thrust chamber wall was established and the propellant combustion performance of monomethylhydrazine (MMH) and nitrogen tetroxide (NTO) was simulated by a simplified multi-step chemical reaction mechanism. The liquid cooling performance of thrust chamber wall was numerically investigated by using the discrete phase model coupled with the wave breakup model and the convection/diffusion controlled model, in which the liquid film coolant is regarded as the discrete phase particles by considering the entrainment and evaporation of liquid coolant droplets in hot combustion gas. The effects of pintle head diameter Dp, oxidant slot height h0 and coolant consumption ratio on liquid cooling performance were discussed. The results demonstrated that smaller Dp and h0 can help to improve the characteristic velocity of the thrust chamber. As the coolant ratio increases from 18% to 24%, the maximum wall temperature of the thrust chamber is reduced by 11% (212 K) with only a 1.3% reduction in characteristic velocity (combustion perfor-mance). The present numerical method and results can provide important guidance for liquid film cooling design of the liquid rocket engine based on pintle injector.
Keyword ：
Cooling performance Discrete phase model Liquid film cooling Liquid rocket engine Pintle injector
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| GB/T 7714 | Zhang, Guodong , Li, Guangxi , Li, Longfei et al. Thermal performance of MMH/NTO rocket thrust chamber based on pintle injector by using liquid film cooling [J]. | APPLIED THERMAL ENGINEERING , 2023 , 223 . |
| MLA | Zhang, Guodong et al. "Thermal performance of MMH/NTO rocket thrust chamber based on pintle injector by using liquid film cooling" . | APPLIED THERMAL ENGINEERING 223 (2023) . |
| APA | Zhang, Guodong , Li, Guangxi , Li, Longfei , Tang, Guihua . Thermal performance of MMH/NTO rocket thrust chamber based on pintle injector by using liquid film cooling . | APPLIED THERMAL ENGINEERING , 2023 , 223 . |
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Abstract ：
The heaters working with supercritical fluids normally suffer from high temperature, high pressure and non-uniform heating, which would lead to thermal fragile and stress failure in practical engineering. However, efficient and accurate methods to predict the comprehensive stress in non-uniformly heating tubes are missing. Besides, to reduce the comprehensive stress, a criterion is required to provide optimization guidance of non -uniformly heating tubes. In present study, the thermal and mechanical performances of three typical non -uniformly heating tubes are numerically investigated using the FVM-FEM method. A generalized thermal de-viation factor (GTDF) is then proposed. The results showed that the GTDF can accurately predict the ratio of comprehensive stress to yield strength and GTDF > 1 indicates the plastic deformation, which is much more convenient and efficient than the conventional structural analysis. Based on the GTDF, two methods of reducing heat flux non-uniformity and enhancing tube-inside heat transfer are proposed to reduce the comprehensive stress. The results show that the unilaterally elliptic dimpled tube reduces the maximum comprehensive stress by 30.8% compared with the smooth tube and also prevents the stress concentration in the dimple zone, which can be employed to reduce the comprehensive stress in various tubes under non-uniformly heating conditions.
Keyword ：
Comprehensive stress Non -uniform heating Stress evaluating criterion Supercritical fluid Tube optimization
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| GB/T 7714 | Li, X. L. , Li, G. X. , Tang, G. H. et al. A generalized thermal deviation factor to evaluate the comprehensive stress of tubes under non-uniform heating [J]. | ENERGY , 2023 , 263 . |
| MLA | Li, X. L. et al. "A generalized thermal deviation factor to evaluate the comprehensive stress of tubes under non-uniform heating" . | ENERGY 263 (2023) . |
| APA | Li, X. L. , Li, G. X. , Tang, G. H. , Fan, Y. H. , Yang, D. L. . A generalized thermal deviation factor to evaluate the comprehensive stress of tubes under non-uniform heating . | ENERGY , 2023 , 263 . |
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Abstract ：
Accessibility to freshwater has become a global issue and many approaches have been developed to tackle this question. One promising way is using radiative coolers to condense dew from the air. This study aims to quantify systematically the effects of droplet diameters, spacial distribution, projected surface coverage ratio, and surface wettabilities on the normal-hemispherical transmittance and cooling performance. The Monte Carlo ray tracing method is employed to simulate the infrared light transfer through the droplets. For the first time, the normal-hemispherical transmittance and cooling performance of radiative cooler with different droplet contact angles were investigated theoretically. The weighted transmittance is found to be independent of droplet spacial distribution, but dependent on droplet (i)diameter, (ii)projected surface coverage ratio, and (iii)contact angle. Results show that the water condensed on the emitting surface can improve the cooling power. A super-hydrophilic PDMS film with a 90% projected surface coverage ratio can reach a cooling power of 109.3 W m(-2). In the process of water condensation, a cooling power loss of up to 23.4 W m(-2) will appear due to surface wettability, so super-hydrophilic surfaces are preferred. These results provide guidance on surface wettability preference for better performance of radiative cooler for direct water condensation.
Keyword ：
Condensation Contact angle Radiative cooling Transmittance
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| GB/T 7714 | Yang, Rui , Wang, Man , Du, Mu et al. Droplet effect on the infrared transmittance of radiative cooler for direct water condensation [J]. | SOLAR ENERGY MATERIALS AND SOLAR CELLS , 2022 , 238 . |
| MLA | Yang, Rui et al. "Droplet effect on the infrared transmittance of radiative cooler for direct water condensation" . | SOLAR ENERGY MATERIALS AND SOLAR CELLS 238 (2022) . |
| APA | Yang, Rui , Wang, Man , Du, Mu , Wang, Xinyu , Tang, G. H. . Droplet effect on the infrared transmittance of radiative cooler for direct water condensation . | SOLAR ENERGY MATERIALS AND SOLAR CELLS , 2022 , 238 . |
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Abstract ：
Anti-propagation and enhanced icephobicity both are critical for anti-icing surfaces. In this work, four types of functional surfaces were prepared to investigate condensation frosting mechanisms (hydrophilic surfaces, hydrophobic slippery lubricant-infused porous surfaces, and two types of superhydrophobic surfaces). Experimental results indicated that no directional icing was identified on both the hydrophilic and slippery surfaces, while it was observed on superhydrophobic surfaces. The mechanisms were explained based on microscopic photos, together with theoretical analysis and Molecular Dynamics simulations. On the hydrophilic surfaces, the initially frozen droplets can induce the icing of some of their neighbours. However, these inter-droplet icing spreading failed to develop into a directional spreading for the whole field of view. On the slippery surfaces, most of the droplets had to freeze locally because the distances among them were beyond the effects of icing bridge. Moreover, the lubricant effects on droplet wetting were investigated using Molecular Dynamics simulation, and the results can support the existence of a lubricant layer beneath droplets. The surface icephobicity was experimentally investigated by measuring the critical shear stress of a frozen droplet. As a whole, the icephobicity of the slippery surface was significantly enhanced. Especially, when the substrate was chilled to -5 degrees C, the high icephobicity of the slippery surface was highlighted by an order of magnitude lower than that on the hydrophilic surface. Also, the slippery surfaces were fabricated based on silica nanoparticles via a commercially coating spray. This method can be of low economic cost for scalable preparation. Overall, the present work can be helpful for developing anti-icing functional surfaces. (C) 2022 Elsevier Ltd. All rights reserved.
Keyword ：
Condensation frost Icephobicity Icing propagation Molecular dynamics simulation Slippery lubricant-infused porous surfaces Superhydrophobic surfaces
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| GB/T 7714 | Jiang, J. , Sheng, Q. , Tang, G. H. et al. Anti-icing propagation and icephobicity of slippery liquid-infused porous surface for condensation frosting [J]. | INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER , 2022 , 190 . |
| MLA | Jiang, J. et al. "Anti-icing propagation and icephobicity of slippery liquid-infused porous surface for condensation frosting" . | INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 190 (2022) . |
| APA | Jiang, J. , Sheng, Q. , Tang, G. H. , Yang, M. Y. , Guo, L. . Anti-icing propagation and icephobicity of slippery liquid-infused porous surface for condensation frosting . | INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER , 2022 , 190 . |
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Abstract ：
It was interesting to experimentally find that the thermal insulation of silica aerogels was improved by doping graphene sheets with high heat conductivity. The underlying mechanism is investigated in the present work from the perspective of gas-solid interaction using a comprehensive analysis of molecular dynamics (MD) simulations, theoretical modeling, and experimental data. The MD-modeled small pores are demonstrated to effectively represent big pores in silica aerogels because of similar heat conduction physics, because it is found that adsorption does not contribute to gas heat conduction. Meanwhile, based on the experimentally measured density, the porous structures are schemati-cally re-engineered using molecular modeling for the first time. The evaluated pore size distributions numerically present a consistency with available experimental data. Inspired by the visualization of the 3D pore structure, we proposed a graphene/silica/nitrogen model to evaluate the role of graphene in heat conduction: it can not only reduce effective gas collision (impede heat transport) but also enhance the gas-solid coupling effect. The former is dominant because of the high porosity, leading to an improvement in thermal insulation. The competition between them can be the reason for the "trade-off" phenomenon in the graphene doping effect in the available experiment.
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| GB/T 7714 | Yang, Mingyang , Sheng, Qiang , Guo, Lin et al. How Gas-Solid Interaction Matters in Graphene-Doped Silica Aerogels [J]. | LANGMUIR , 2022 , 38 (7) : 2238-2247 . |
| MLA | Yang, Mingyang et al. "How Gas-Solid Interaction Matters in Graphene-Doped Silica Aerogels" . | LANGMUIR 38 . 7 (2022) : 2238-2247 . |
| APA | Yang, Mingyang , Sheng, Qiang , Guo, Lin , Zhang, Hu , Tang, Guihua . How Gas-Solid Interaction Matters in Graphene-Doped Silica Aerogels . | LANGMUIR , 2022 , 38 (7) , 2238-2247 . |
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Abstract ：
Due to serious solar absorption and poor thermal insulation on the cold side, current daytime radiative cooling falls far short of the theoretical potential. The mesoporous film can be used for both thermal insulation and optical selection. In this study, the radiative properties of infrared transparent mesoporous materials are investigated. The Diffusion Limited Cluster Aggregation algorithm is employed to reproduce the micro-structures of the mesoporous materials. The structure-dependent normal hemispherical transmittance is predicted by the combination of discrete dipole approximation and Monte Carlo method. The effects of material type and structure characteristics (particle size, volume fraction and cover thickness) on the infrared transmittance and all-day radiative cooling performance are quantified. The results show that the polyethylene (PE) aerogel achieves the best thermal insulation performance and good spectral selectivity. It can work as a thermally insulating barrier and an infrared transparent window for the radiative cooling surface. By integrating with PE aerogel, the radiative cooling surface can enable the passive cooling up to 13 K below the ambient temperature during the day and 15 K below the ambient temperature during the night at a wind speed of 2.8 m/s. This work provides an optimal design of optically selective and thermally insulating mesoporous materials in passive all-day radiative cooling applications.
Keyword ：
Mesoporous material Radiative cooling Thermal insulation Transmittance
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| GB/T 7714 | Huang, Maoquan , Yu, Xiyu , Wan, Jiacheng et al. All-day effective radiative cooling by optically selective and thermally insulating mesoporous materials [J]. | SOLAR ENERGY , 2022 , 235 : 170-179 . |
| MLA | Huang, Maoquan et al. "All-day effective radiative cooling by optically selective and thermally insulating mesoporous materials" . | SOLAR ENERGY 235 (2022) : 170-179 . |
| APA | Huang, Maoquan , Yu, Xiyu , Wan, Jiacheng , Du, Mu , Wang, Xinyu , Sun, Qie et al. All-day effective radiative cooling by optically selective and thermally insulating mesoporous materials . | SOLAR ENERGY , 2022 , 235 , 170-179 . |
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Abstract ：
This work presents a design of 1000 MW S-CO2 coal-fired power system, containing not only a new methodology of S-CO2 power system modeling, but also the specific directions for engineering design. The coupling between computational fluid dynamic simulations at boiler scale and the mathematical modeling of the thermal cycle facilitates a high reliability of the comprehensive design. Our analysis helps identify key questions and then delivers specific directions for engineering design, especially for the pressure drop penalty in tail flue and thermal-hydraulic performance of cooling wall. The proposed flue split method coupled with parallel utilization method can not only effectively reduce the pressure drop penalty but also simplify the system heater configuration. Moreover, the thermal performance of S -CO2 cooling wall is improved by using the flue gas recirculation and cooling wall arrangement optimization. The optimized position and proportion of flue gas extraction are further obtained. Comprehensively, the proposed design of S-CO2 coal-fired power system enhances the system net efficiency up to 51.00%, with an efficient utilization of residual heat and cooling wall temperature below 700 degrees C. (c) 2021 Elsevier Ltd. All rights reserved.
Keyword ：
Modeling methodology Multiscale S-CO 2 coal-fired power plant System net efficiency Thermal-hydraulic performance
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| GB/T 7714 | Fan, Y. H. , Yang, D. L. , Tang, G. H. et al. Design of S-CO2 coal-fired power system based on the multiscale analysis platform [J]. | ENERGY , 2022 , 240 . |
| MLA | Fan, Y. H. et al. "Design of S-CO2 coal-fired power system based on the multiscale analysis platform" . | ENERGY 240 (2022) . |
| APA | Fan, Y. H. , Yang, D. L. , Tang, G. H. , Sheng, Q. , Li, X. L. . Design of S-CO2 coal-fired power system based on the multiscale analysis platform . | ENERGY , 2022 , 240 . |
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Abstract ：
Silica aerogels are extensively used for thermal insulation at high temperatures. However, it has been experimentally found that high temperature can change the pore structure and undermine thermal insu-lation. The mechanism of high temperature influence is unclear due to the limited resolution of experi-mental observations. In the present work, molecular dynamics simulations and theoretical modeling were combined to investigate the effects of high temperature on pore structures and heat conduction. At the scale of nanoparticles, the structural evolution induced by the sintering process of silica aerogels was nu-merically investigated. The melting process of a single silica nanoparticle can be divided into three stages, and it was found that extending the stage of surface diffusion can improve the thermal stability of sil-ica nanoparticles. At the scale of particle assembly, the contact diameter between adjacent particles was identified and numerically evaluated. At the scale of bulk material, a theoretical model was developed to predict the solid thermal conductivity by considering both the temperature effect on the intrinsic thermal conductivity of backbone and the effect of nanoparticle size. A good agreement was found between the present model and available experimental data. An insightful discussion of the existing theoretical mod-els and experimental data was also presented. The present work can inspire further cross-scale modeling of silica aerogels and may pave the way for the development of silica aerogels with high stability and thermal insulation at high temperatures. (c) 2022 Elsevier Ltd. All rights reserved.
Keyword ：
Heat conduction Molecular dynamics simulation Nanoparticles Silica aerogel Sintering mechanism
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| GB/T 7714 | Yang, M. Y. , Tang, G. H. , Sheng, Q. et al. Atomic-level sintering mechanism of silica aerogels at high temperatures: structure evolution and solid thermal conductivity [J]. | INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER , 2022 , 199 . |
| MLA | Yang, M. Y. et al. "Atomic-level sintering mechanism of silica aerogels at high temperatures: structure evolution and solid thermal conductivity" . | INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 199 (2022) . |
| APA | Yang, M. Y. , Tang, G. H. , Sheng, Q. , Guo, L. , Zhang, H. . Atomic-level sintering mechanism of silica aerogels at high temperatures: structure evolution and solid thermal conductivity . | INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER , 2022 , 199 . |
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Abstract ：
The thermal radiation of micron-sized condensed phase particles plays a dominant role during the heat transfer process in aluminized Solid Rocket Motors (SRMs). Open research mainly focuses on the radiative properties of alumina particles while the study considering the presence of aluminum is lacking. In addition, the thermal radiation inside the SRM with consideration of the participating particles is seldom studied. In this work, the multiscale method of predicting the thermal environment inside SRMs is established from the particle radiation at microscale to the two-phase flow and heat transfer at macroscale. The effective gray radiative properties of individual particles (alumina, aluminum, and hybrid alumina/aluminum) and particles cloud are investigated with the Mie theory and approximate method. Then a numerical method for predicting the thermal environment inside SRMs with considering particle radiation is established and applied in a subscale motor. The convective and radiative heat flux distributions along inner wall of motor are obtained, and it is found that the heat transfer in the combustion chamber is dominated by thermal radiation and the radiative heat flux is essentially a constant of 5.6-6.8 MW/m2. The convective heat transfer plays a dominant role in the nozzle and the heat flux reaches the maximum value of 11.2 MW/m(2) near the throat. As the combustion efficiency of aluminum drops, the radiative heat flux remains unchanged in most regions and increases slightly along the diverging section wall of the nozzle. (C)& nbsp;2021 Chinese Society of Aeronautics and Astronautics and Beihang University. Production and hosting by Elsevier Ltd.& nbsp;
Keyword ：
Alumina Aluminum Condensed phase particle Radiative heat transfer Radiative properties Solid rocket motor
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| GB/T 7714 | Hao, Xuefan , Zhang, Hu , Hou, Xiao et al. Radiative properties of alumina/aluminum particles and influence on radiative heat transfer in solid rocket motor [J]. | CHINESE JOURNAL OF AERONAUTICS , 2022 , 35 (2) : 98-116 . |
| MLA | Hao, Xuefan et al. "Radiative properties of alumina/aluminum particles and influence on radiative heat transfer in solid rocket motor" . | CHINESE JOURNAL OF AERONAUTICS 35 . 2 (2022) : 98-116 . |
| APA | Hao, Xuefan , Zhang, Hu , Hou, Xiao , Tang, Guihua . Radiative properties of alumina/aluminum particles and influence on radiative heat transfer in solid rocket motor . | CHINESE JOURNAL OF AERONAUTICS , 2022 , 35 (2) , 98-116 . |
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Abstract ：
Doping plasmonic nanoparticles in aerogel to achieve optical selectivity can significantly extend its applicable prospect. An optical selectivity aerogel by doping with gold/silver nanoparticles is introduced in this work. The radiative properties of optical selectivity aerogels were predicted by the combination of T-matrix and Monte Carlo method. The effects of morphology, aspect ratio, size, and doping concentration of nanoparticles on the spectral selectivity of the hybrid aerogels were discussed. The results show that the aspect ratio of the plasmonic particle affects the multispectral conversion of solar radiation significantly. The aerogel containing silver nanocylinders of AR = 0.2 and ITO nanospheres achieves the highest solar energy absorption. Even with an extremely low doping concentration (fv,ITO = 0.01% and fv,p = 0.001%), the absorption to solar radiation can be increased by over 75% for a 1 cm thick aerogel, which can be employed for efficient solar desalination. In addition, by doping with silver nanocylinders (AR = 0.15), the hybrid aerogel is penetrable to the visible light but absorbs infrared solar radiation for the application of anti-fogging/deicing. The silver nanospheroids (AR = 0.3)-based hybrid aerogel can serve as a greenhouse envelope for augmented photosynthesis to absorb the green light while allowing most of the other wavelengths of solar radiation to pass through. (c) 2022 Elsevier Ltd. All rights reserved.
Keyword ：
LSPR Optical selectivity aerogels Plasmonic nanoparticles T-matrix method
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| GB/T 7714 | Yu, Xiyu , Huang, Maoquan , Wang, Xinyu et al. Toward optical selectivity aerogels by plasmonic nanoparticles doping [J]. | RENEWABLE ENERGY , 2022 , 190 : 741-751 . |
| MLA | Yu, Xiyu et al. "Toward optical selectivity aerogels by plasmonic nanoparticles doping" . | RENEWABLE ENERGY 190 (2022) : 741-751 . |
| APA | Yu, Xiyu , Huang, Maoquan , Wang, Xinyu , Sun, Qie , Tang, G. H. , Du, Mu . Toward optical selectivity aerogels by plasmonic nanoparticles doping . | RENEWABLE ENERGY , 2022 , 190 , 741-751 . |
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