Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging f...Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging from 278.15 K to 318.15 K.The solubility in each system was found to be positively correlated with temperature.Furthermore,solubility data were analyzed using four equations:the modified Apelblat equation,Van’t Hoff equation,λh equation and CNIBS/R-K equations,and they provided satisfactory results for both two systems.The average root-mean-square deviation(105RMSD)values for these models were less than 13.93.Calculations utilizing the Van’t Hoff equation and Gibbs equations facilitated the derivation of apparent thermodynamic properties of NTO dissolution in the two systems,including values for Gibbs free energy,enthalpy and entropy.The%ζ_(H)is larger than%ζ_(TS),and all the%ζ_(H)data are≥58.63%,indicating that the enthalpy make a greater contribution than entropy to theΔG_(soln)^(Θ).展开更多
TiN,which is ubiquitous in Ti-bearing steel,has a critical influence on both the mechanical properties and the welding process of steel,and therefore researche on the precipitation behavior of TiN in molten steel bath...TiN,which is ubiquitous in Ti-bearing steel,has a critical influence on both the mechanical properties and the welding process of steel,and therefore researche on the precipitation behavior of TiN in molten steel bath is of great significance.In this paper,Ti-bearing peritectic steel was taken as the study object and FactSage was adopted to explore how the precipitation behavior of typical inclusions in steel was affected by the steel composition.Furthermore,microsegregation models were used to analyze the precipitation process of TiN at solidification front,and the calculation results were finally verified by scanning electron microscope(SEM).Research showed that a multitude of dispersed particles of high melting oxide MgAl2O4 or MgO always existed in molten steel after magnesium treatment.In consideration of the segregation and enrichment of solute elements at the solidification front,the Ohnaka microsegregation model was employed to compute the precipitation during solidification.In the event of the solid fraction reaching 0.95 or more,the concentration product of[Ti][N]at the solidification front exceeded the equilibrium concentration product,then TiN began to precipitate.MgO or MgAl2O4 cores were generally found in TiN particles of peritectic steel after the magnesium treatment,which was consistent with the thermodynamic calculation results.Moreover,the average size of TiN particles was reduced by approximately 49%.This demonstrated that Mg-rich high melting inclusions were formed after the magnesium treatment,by which the heterogeneous nucleation of TiN was promoted it;therefore,favorable nucleation sites were provided for further refining the high-temperature ferrite phase.展开更多
In this article, we considers the thermodynamics analysis of creeping viscous nanofluid flow in a horizontal ciliated tube under the effects of a uniform magnetic field and porous medium. Moreover, energy analysis is ...In this article, we considers the thermodynamics analysis of creeping viscous nanofluid flow in a horizontal ciliated tube under the effects of a uniform magnetic field and porous medium. Moreover, energy analysis is performed in the presence of an internal heat source and thermal radiation phenomena. The thermal conductivity of base fluid water is strengthened by considering the carbon nanotubes (CNTs). Mathematical formulation operated, results in a set of non-linear coupled partial differential equations. The governed differential system is transformed into an ordinary differential system by considering suitable similarity variables. Exact solutions in the closed form are computed for the temperature, momentum and pressure gradient profiles. In this study, special attention is devoted to the electrical conductivity of the CNTs. Streamlines patterns are also discussed to witness the flow lines for different parameters. Thermodynamics analysis shows that entropy of the current flow system is an increasing function of Brinkmann number, magnetic parameter, nanoparticle concentration parameter and Darcy number.展开更多
Numerous innovative heat recovery-to-power technologies have been resourcefully and technologically exploited to bridge the growing gap between energy needs and its sustainable and affordable supply.Among them,the pro...Numerous innovative heat recovery-to-power technologies have been resourcefully and technologically exploited to bridge the growing gap between energy needs and its sustainable and affordable supply.Among them,the proposed trilateral-cycle(TLC) power system exhibits high thermodynamic efficiency during heat recovery-to-power from low-to-medium temperature heat sources.The TLCs are proposed and analysed using n-pentane as working fluid for waste heat recovery-to-power generation from low-grade heat source to evaluate the thermodynamic efficiency of the cycles.Four different single stage TLC configurations with distinct working principles are modelled thermodynamically using engineering equation solver.Based on the thermodynamic framework,thermodynamic performance simulation and efficiency analysis of the cycles as well as the exergy efficiencies of the heating and condensing processes are carried out and compared in their efficiency.The results show that the simple TLC,recuperated TLC,reheat TLC and regenerative TLC operating at subcritical conditions with cycle high temperature of 473 K can attain thermal efficiencies of 21.97%,23.91%,22.07% and 22.9%,respectively.The recuperated TLC attains the highest thermodynamic efficiency at the cycle high temperature because of its lowest exergy destruction rates in the heat exchanger and condenser.The efficiency analysis carried out would assist in guiding thermodynamic process development and thermal integration of the proposed cycles.展开更多
二氧化碳储能(carbon dioxide energy storage,CES)是一种兼具储能效率高、地理适配性高、安全环保的新型压缩气体储能技术,受到业内广泛关注。该文提出一种耦合聚光式光热利用的超临界二氧化碳储能发电系统(supercritical carbon dioxi...二氧化碳储能(carbon dioxide energy storage,CES)是一种兼具储能效率高、地理适配性高、安全环保的新型压缩气体储能技术,受到业内广泛关注。该文提出一种耦合聚光式光热利用的超临界二氧化碳储能发电系统(supercritical carbon dioxide energy storage-concentrated solar thermal power,SCES-CSTP)和采用分流再压缩、两级回热的改进系统(supercritical carbon dioxide energy storage-concentrated solar thermal power+split compression,SCES-CSTP+SC),探索了光热熔融盐单元与超临界二氧化碳储能的互补优势。研究发现,提高储能压力比和加热温度可以提高储能效率和储能密度,但储能压力比存在最佳值;优化后的SCES-CSTP系统在储能压力比为4.0,加热温度为773.15 K时,储能效率、电-电效率分别为72.37%和432.9%,储能密度为12.94 kW·h/m^(3),(火用)效率为74.4%。SCES-CSTP+SC系统显著增强了回热器传热和系统性能,优选出最佳分流比为0.15和加热温度713.15 K时储能效率最高为75.51%,总(火用)损降低至526.62 kW,(火用)效率提升至77.7%。结果表明,光热对超临界CO_(2)储能系统性能提升具有积极影响。展开更多
昆仑能源湖北黄冈液化天然气工厂是中国唯一的百万吨级天然气液化工厂,经过10年的平稳运行,证明我国自主开发的百万吨级天然气液化工艺技术和国产化装备可靠性较高。中国已实现百万吨级液化天然气工厂的自主建设和运营,但在工艺优化和...昆仑能源湖北黄冈液化天然气工厂是中国唯一的百万吨级天然气液化工厂,经过10年的平稳运行,证明我国自主开发的百万吨级天然气液化工艺技术和国产化装备可靠性较高。中国已实现百万吨级液化天然气工厂的自主建设和运营,但在工艺优化和降低能耗方面仍存在较大提升空间。为此,以昆仑能源湖北黄冈液化天然气工厂为例,重点对该工厂的工艺流程进行了介绍和模拟验证,并在此基础上对工艺参数进行了优化。研究结果表明:(1)采用工厂实际运行数据对多级单组分制冷天然气液化工艺(Multistage Single Component refrigeration natural gas liquefaction process,MSC)的计算模型进行了验证,并采用热力学分析方法对MSC工艺的换热系统进行了优化;(2)模拟计算结果和实际运行数据吻合度高,单位能耗数据相差2.40%,证实计算模型可信度高;(3)基于热力学分析,优化了对数平均温差,换热过程的总?损降低了15.67%,单位能耗为每千克LNG 0.318 k W·h,比验证计算模型下降2.15%。结论认为,研究成果可指导该工厂下一步的节能降耗,同时为开发单线规模800×10^(4) t/a的超大型天然气液化成套技术提供理论支撑,实践经验对指导中国超大型天然气液化工厂高质量发展具有重要的工程应用价值。展开更多
文摘Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging from 278.15 K to 318.15 K.The solubility in each system was found to be positively correlated with temperature.Furthermore,solubility data were analyzed using four equations:the modified Apelblat equation,Van’t Hoff equation,λh equation and CNIBS/R-K equations,and they provided satisfactory results for both two systems.The average root-mean-square deviation(105RMSD)values for these models were less than 13.93.Calculations utilizing the Van’t Hoff equation and Gibbs equations facilitated the derivation of apparent thermodynamic properties of NTO dissolution in the two systems,including values for Gibbs free energy,enthalpy and entropy.The%ζ_(H)is larger than%ζ_(TS),and all the%ζ_(H)data are≥58.63%,indicating that the enthalpy make a greater contribution than entropy to theΔG_(soln)^(Θ).
基金Projects(51774208,52074186,U1860205)supported by the National Natural Science Foundation of China。
文摘TiN,which is ubiquitous in Ti-bearing steel,has a critical influence on both the mechanical properties and the welding process of steel,and therefore researche on the precipitation behavior of TiN in molten steel bath is of great significance.In this paper,Ti-bearing peritectic steel was taken as the study object and FactSage was adopted to explore how the precipitation behavior of typical inclusions in steel was affected by the steel composition.Furthermore,microsegregation models were used to analyze the precipitation process of TiN at solidification front,and the calculation results were finally verified by scanning electron microscope(SEM).Research showed that a multitude of dispersed particles of high melting oxide MgAl2O4 or MgO always existed in molten steel after magnesium treatment.In consideration of the segregation and enrichment of solute elements at the solidification front,the Ohnaka microsegregation model was employed to compute the precipitation during solidification.In the event of the solid fraction reaching 0.95 or more,the concentration product of[Ti][N]at the solidification front exceeded the equilibrium concentration product,then TiN began to precipitate.MgO or MgAl2O4 cores were generally found in TiN particles of peritectic steel after the magnesium treatment,which was consistent with the thermodynamic calculation results.Moreover,the average size of TiN particles was reduced by approximately 49%.This demonstrated that Mg-rich high melting inclusions were formed after the magnesium treatment,by which the heterogeneous nucleation of TiN was promoted it;therefore,favorable nucleation sites were provided for further refining the high-temperature ferrite phase.
文摘In this article, we considers the thermodynamics analysis of creeping viscous nanofluid flow in a horizontal ciliated tube under the effects of a uniform magnetic field and porous medium. Moreover, energy analysis is performed in the presence of an internal heat source and thermal radiation phenomena. The thermal conductivity of base fluid water is strengthened by considering the carbon nanotubes (CNTs). Mathematical formulation operated, results in a set of non-linear coupled partial differential equations. The governed differential system is transformed into an ordinary differential system by considering suitable similarity variables. Exact solutions in the closed form are computed for the temperature, momentum and pressure gradient profiles. In this study, special attention is devoted to the electrical conductivity of the CNTs. Streamlines patterns are also discussed to witness the flow lines for different parameters. Thermodynamics analysis shows that entropy of the current flow system is an increasing function of Brinkmann number, magnetic parameter, nanoparticle concentration parameter and Darcy number.
基金The University of Ilorin,Nigeria financially supported this research through scholarship grant from Tertiary Education Trust Fund
文摘Numerous innovative heat recovery-to-power technologies have been resourcefully and technologically exploited to bridge the growing gap between energy needs and its sustainable and affordable supply.Among them,the proposed trilateral-cycle(TLC) power system exhibits high thermodynamic efficiency during heat recovery-to-power from low-to-medium temperature heat sources.The TLCs are proposed and analysed using n-pentane as working fluid for waste heat recovery-to-power generation from low-grade heat source to evaluate the thermodynamic efficiency of the cycles.Four different single stage TLC configurations with distinct working principles are modelled thermodynamically using engineering equation solver.Based on the thermodynamic framework,thermodynamic performance simulation and efficiency analysis of the cycles as well as the exergy efficiencies of the heating and condensing processes are carried out and compared in their efficiency.The results show that the simple TLC,recuperated TLC,reheat TLC and regenerative TLC operating at subcritical conditions with cycle high temperature of 473 K can attain thermal efficiencies of 21.97%,23.91%,22.07% and 22.9%,respectively.The recuperated TLC attains the highest thermodynamic efficiency at the cycle high temperature because of its lowest exergy destruction rates in the heat exchanger and condenser.The efficiency analysis carried out would assist in guiding thermodynamic process development and thermal integration of the proposed cycles.
文摘二氧化碳储能(carbon dioxide energy storage,CES)是一种兼具储能效率高、地理适配性高、安全环保的新型压缩气体储能技术,受到业内广泛关注。该文提出一种耦合聚光式光热利用的超临界二氧化碳储能发电系统(supercritical carbon dioxide energy storage-concentrated solar thermal power,SCES-CSTP)和采用分流再压缩、两级回热的改进系统(supercritical carbon dioxide energy storage-concentrated solar thermal power+split compression,SCES-CSTP+SC),探索了光热熔融盐单元与超临界二氧化碳储能的互补优势。研究发现,提高储能压力比和加热温度可以提高储能效率和储能密度,但储能压力比存在最佳值;优化后的SCES-CSTP系统在储能压力比为4.0,加热温度为773.15 K时,储能效率、电-电效率分别为72.37%和432.9%,储能密度为12.94 kW·h/m^(3),(火用)效率为74.4%。SCES-CSTP+SC系统显著增强了回热器传热和系统性能,优选出最佳分流比为0.15和加热温度713.15 K时储能效率最高为75.51%,总(火用)损降低至526.62 kW,(火用)效率提升至77.7%。结果表明,光热对超临界CO_(2)储能系统性能提升具有积极影响。
文摘昆仑能源湖北黄冈液化天然气工厂是中国唯一的百万吨级天然气液化工厂,经过10年的平稳运行,证明我国自主开发的百万吨级天然气液化工艺技术和国产化装备可靠性较高。中国已实现百万吨级液化天然气工厂的自主建设和运营,但在工艺优化和降低能耗方面仍存在较大提升空间。为此,以昆仑能源湖北黄冈液化天然气工厂为例,重点对该工厂的工艺流程进行了介绍和模拟验证,并在此基础上对工艺参数进行了优化。研究结果表明:(1)采用工厂实际运行数据对多级单组分制冷天然气液化工艺(Multistage Single Component refrigeration natural gas liquefaction process,MSC)的计算模型进行了验证,并采用热力学分析方法对MSC工艺的换热系统进行了优化;(2)模拟计算结果和实际运行数据吻合度高,单位能耗数据相差2.40%,证实计算模型可信度高;(3)基于热力学分析,优化了对数平均温差,换热过程的总?损降低了15.67%,单位能耗为每千克LNG 0.318 k W·h,比验证计算模型下降2.15%。结论认为,研究成果可指导该工厂下一步的节能降耗,同时为开发单线规模800×10^(4) t/a的超大型天然气液化成套技术提供理论支撑,实践经验对指导中国超大型天然气液化工厂高质量发展具有重要的工程应用价值。
