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学者姓名：唐桂华
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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 ：
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 ：
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 ：
Supercritical carbon dioxide (S-CO2) coal-fired power systems have been widely investigated due to its high efficiency and compactness. These power systems can range between 50 and 1000 MW and thus the corresponding boilers actually operate under dramatically different conditions. It is necessary to investigate the inherent relationship among different capacity S-CO2 boilers, which not only bring new theoretical understandings but also help improve practical designs. In this work, a unified model is proposed to investigate both thermal-hydraulic and thermodynamic performance. Furthermore, it is applied to evaluate the relationship between power capacity and boiler configuration. It is shown that small capacity furnaces suffer from overheating in the furnace wall and the optimized cooling wall is suggested to tackle this issue. Moreover, it is found that high pressure drop in the cooling wall of large capacity furnaces results in significant penalty on the cycle efficiency. For the popular 1000 MW boiler, an optimized configuration is suggested by moving the second reheating into the horizontal flue of boiler, achieving a lower pressure drop and an improved cycle efficiency from 35.4% to 50.09%. Finally, three recommendations for the capacity-dependent configurations are presented.(C) 2022 Elsevier Ltd. All rights reserved.
Keyword ：
Capacity-dependent configuration Cooling-wall temperature Cycle efficiency S-CO2 coal-fired boiler
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| GB/T 7714 | Yang, D. L. , Tang, G. H. , Li, X. L. et al. Capacity-dependent configurations of S-CO2 coal-fired boiler by overall analysis with a unified model [J]. | ENERGY , 2022 , 245 . |
| MLA | Yang, D. L. et al. "Capacity-dependent configurations of S-CO2 coal-fired boiler by overall analysis with a unified model" . | ENERGY 245 (2022) . |
| APA | Yang, D. L. , Tang, G. H. , Li, X. L. , Fan, Y. H. . Capacity-dependent configurations of S-CO2 coal-fired boiler by overall analysis with a unified model . | ENERGY , 2022 , 245 . |
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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 ：
Recuperator is an important component in supercritical carbon dioxide Brayton cycle. However, open literature mainly focused on the performance of recuperator in component scale but the effect of its thermal-hydraulic performance on the cycle efficiency was seldom concerned. Besides, to be more convenient in practical appli-cations, a criterion for thermal-hydraulic evaluation of recuperators in supercritical carbon dioxide Brayton cycle is needed to avoid the coupling analysis of recuperator design and cycle design. In the present study, an integrated model is developed by combining the supercritical carbon dioxide Brayton cycle with the recuperator of a printed circuit heat exchanger. Based on the integrated model, the effects of design parameters of recu-perator on the cycle performance are discussed. It is shown that ultra-large Reynolds number and effectiveness fail to improve the cycle efficiency and are not recommended due to the caused large pressure drop. The effects of conventional performance evaluation criteria and the ratio of heat transfer rate to pressure drop on cycle efficiency are also examined. It is indicated that the existing criteria are not sufficient to evaluate the effect of recuperator channel configuration on cycle efficiency. The performance recovery coefficient with value between 0 and 1 is finally proposed and validated to be an effective and convenient criterion as well as straightforward to various cycle layouts with other types of recuperators.
Keyword ：
Cycle efficiency Performance recovery coefficient Printed circuit heat exchanger Supercritical carbon dioxide Brayton cycle Thermal-hydraulic evaluation
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| GB/T 7714 | Li, X. L. , Tang, G. H. , Fan, Y. H. et al. A performance recovery coefficient for thermal-hydraulic evaluation of recuperator in supercritical carbon dioxide Brayton cycle [J]. | ENERGY CONVERSION AND MANAGEMENT , 2022 , 256 . |
| MLA | Li, X. L. et al. "A performance recovery coefficient for thermal-hydraulic evaluation of recuperator in supercritical carbon dioxide Brayton cycle" . | ENERGY CONVERSION AND MANAGEMENT 256 (2022) . |
| APA | Li, X. L. , Tang, G. H. , Fan, Y. H. , Yang, D. L. . A performance recovery coefficient for thermal-hydraulic evaluation of recuperator in supercritical carbon dioxide Brayton cycle . | ENERGY CONVERSION AND MANAGEMENT , 2022 , 256 . |
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