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Influence of Metal Material Properties on Heat and Mass Transfer into Thermal Protection Surface with phenomenological Catalytic model

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Journal of Thermal Science 2023年第3期32卷 993-1006页

作者： LI Qin YANG Xiaofeng DONG Wei DU Yanxia School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Aerodynamics China Aerodynamics Research and Development CenterMianyang 621000China

Surface heterogeneous catalysis in a high-enthalpy dissociated environment leads to a remarkable enhancement of aerodynamic heating into the thermal protection surface of hypersonic aircraft.To more accurately predict this catalytic heating,a kinetic catalytic model was constructed.This model involved four elementary reactions,the rates of which were determined on mean-field approximation and surface steady-state reaction assumption.By coupling this model into the viscous wall boundary condition of computational fluid dynamics(CFD)solver,the influences of metal material catalytic properties on heat and mass transfer into thermal protection materials were numerically investigated.Numerical results showed that atomic oxygen recombination catalyzed by surface material accounts for a major contribution to aerodynamic heating and thus variation in recombination rates from different materials leads to the significant difference in surface heat fluxes.From a comparative analysis of various materials,the catalytic activity increases from the inert platinum(Pt)to nickel(Ni)and finally to the active copper(Cu).As a result,the catalytic heating on Cu surface was more than twice of that on Pt surface.Further parametrical research revealed that the proper layout of inert material at the nose of aircraft could prevent stagnation catalytic heating from thermal damage by carrying near-wall dissociated atoms from the stagnation zone downstream.The material-relied heterogeneous catalysis mechanism in this study provides some technical support for the thermal protection system design of hypersonic aircraft.

关键词： aerodynamic heating chemical non-equilibrium flow heterogeneous catalysis phenomenological model high-temperature interface effects

phenomenological model for torsional galloping of an elastic flat plate due to hydrodynamic loads

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Journal of Hydrodynamics 2014年第1期26卷 57-65页

作者： FERNANDES Antonio Carlos ARMANDEI Mohammadmehdi Department of Naval and Ocean Engineering COPPE/UFRJ

This study investigates the torsional galloping phenomenon, an instability type flow-induced oscillation, in an elastic stru-cture due to hydrodynamic loads into the water current. The structure applied here is a rectangular flat plate with an elastic axis in its mid-chord length. The elasticity is provided by torsion spring. The flat plate has only one degree of freedom which is rotation in pure yaw about its axis. It is observed that as the current speed is higher than a critical velocity, the flat plate becomes unstable. The instability leads to torsional galloping occurrence, as a result of which the flat plate begins to yaw about the elastic axis. By testing two different chord lengths each with several torsion spring rates, the flat plate behavior is investigated and three different responses are recognized. Then, a phenomenological model is developed with the original kernel in the form of the van der Pol-Duffing equa-tion. The model explains these three responses observed experimentally.

关键词： torsional galloping flow-induced oscillation phenomenological model van der Pol-Duffing equation

A Generalized phenomenological model to Simulate Complex Chemical Processes

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A Generalized Phenomenological Model to Simulate Complex Che...

A comparative study of 85 hyperelastic constitutive models for both unfilled rubber and highly filled rubber nanocomposite material

第一届国际测量仪器与测试自动化学术会议

作者： Zheng Rao Wang Kuisheng Wang Yun ( Beijing University of Chemical Technology Beijing 100029 China) ( Beijing University of Chinese Medicine Beijing 100102 China)

＜正＞The complex chemical processes are composed of many different nonlinear sub-systems, possibly including continual dynamical systems, discrete events dynamic systems and hybrid dynamical systems. The analytical modeling and simulation of complex chemical processes is time-consuming and the model-based fault detection methodology does not work well on these systems. In order to provide a practical modeling method in the simulation and the fault detection of complex systems , a generalized system and its phenomenological model were proposed in the paper. The fault detection method based on the phenomenological model is explored. Using TE process as example, the modeling capability of the method is analyzed. The results indicated that the simple phenomenological model could be used in the simulation and fault detection of TE process in some specific conditions.

关键词： Complex chemical process phenomenological model fault detection.

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Nano Materials Science 2022年第2期4卷 64-82页

作者： Hong He Qiang Zhang Yaru Zhang Jianfeng Chen Liqun Zhang Fanzhu Li State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing100029China College of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing100029China Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials Beijing University of Chemical TechnologyBeijing100029China

Nonlinear finite element analysis is widely used for structural optimization of the design and the reliability analysis of complex elastomeric components.However,high-precision numerical results cannot be achieved without reliable strain energy functions(SEFs)of the rubber or rubber nanocomposite material.Although hyperelastic constitutive models have been studied for nearly 80 years,selecting one that accurately describes rubber's mechanical response is still a challenge.This work reviews 85 isotropic SEFs based on both the phenomenological theory and the micromechanical network theory proposed from the 1940s to 2019.A fitting algorithm which can realize the automatic fitting optimization and determination of the parameters of all SEFs reviewed is developed.The ability of each SEF to reproduce the experimental data of both the unfilled and highly filled rubber nanocomposite is quantitatively assessed based on a new proposed evaluation index.The top 30 SEFs for the unfilled rubber and the top 14 SEFs for the highly filled rubber nanocomposite are presented in the ranking lists.Finally,some suggestions on how to select an appropriate hyperelastic constitutive model are given,and the perspective on the future progress of constitutive models is summarized.

关键词： Rubber-like materials Hyperelastic constitutive model Strain energy function phenomenological model Micromechanical network model UHYPER subroutine

A minimal model for the auxetic response of liquid crystal elastomers

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Chinese Physics B 2022年第10期31卷 253-255页

作者：於冰宇高袁晨曦郑斌孟凡龙方羽叶方富欧阳钟灿 CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Beijing 101 Middle School Beijing 100091China Wenzhou Institute University of Chinese Academy of SciencesWenzhou 325000China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Oujiang Laboratory(Zhejiang Laboratory for Regenerative Medicine Vision and Brain Health)Wenzhou 325000China

We develop a minimal phenomenological model to describe the auxetic response recently observed in liquid crystal elastomers, and further determine by theoretical calculation the critical condition required for the aux... 详细信息

关键词： auxetic response liquid crystal elastomers phenomenological model

Effect of curing, capillary action, and groundwater level increment on geotechnical properties of lime concrete: Experimental and prediction studies

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第4期9卷 638-647页

作者： Mohammad Saberian Soheil Jahandari Jie Li Farzad Zivari School of Engineering RMIT University Melbourne Australia Department of Geotechnical Engineering Graduate University of Advanced Technology Kerman Iran Department of Civil Engineering Shahid Bahonar University of Kerman Kerman Iran

Lime concrete and lime treatment are two attractive techniques for geotechnical engineers.However,researches have rarely been carried out to study the effects of moisture and capillary action due to increasing groundwater level on geotechnical properties of lime concrete.The aim of this study is to investigate the effects of curing time and degree of saturation on some of geotechnical properties of lime concrete such as unconfined compressive strength(UCS),secant modulus(ES),failure strain,brittleness index(IB),and deformability index(ID) using unconfined compression tests.First of all,geotechnical and chemical properties of used materials were determined.After curing times of 14 d,28 d,45 d,and 60 d in laboratory condition,the specimens were exposed to saturation levels ranging from 0 to 100%.The results showed that the moisture and curing time have significant effects on the properties of lime concrete.Based on the results of scanning electron micrograph(SEM) test,it was observed that the specimen was characterized by a rather well-structured matrix since both the filling of a large proportion of the coarse-grained soil voids by clay and the pozzolanic activity of lime led to retaining less pore water in the specimen,increasing the UCS and ES,and consequently resisting against swelling and shrinkage of the clay soil.Moreover,due to the pozzolanic reactions and reduction of water,by increasing the curing time and decreasing the degrees of saturation,UCS,ES,and IBincreased,and IDdecreased.Based on the experimental results,a phenomenological model was used to develop equations for predicting the properties in relation to the ratio of degree of saturation/curing time.The results showed that there was a good correlation(almost R2> 90%) between the measured parameters and the estimated ones given by the predicted equations.

关键词： Lime concrete Degree of saturation Curing time Unconfined compressive strength(UCS) Secant modulus Failure strain Deformability and brittleness indices phenomenological model

RECENT DEVELOPMENTS IN FLOW FILM BOILING HEAT TRANSFER

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Progress in Natural Science:Materials International 1992年第6期 481-490页

作者：王补宣石德惠彭晓峰马骥 Beijing 100084 Institute for Thermal Science and Engineering Tsinghua University PRC

Ⅰ.INTRODUCTIONFilm boiling heat transfer dates from the so-called “Leidenfrost phenomenon”,whichwas found through experiments in 1756.That is,liquid droplets dance on the surface and afilm of superheated vapor will exist between the heating surface and the bulk of liquid.Thefilm serves as a thermal insulation layer,and hence,the surface temperature is much higherthan that for nucleate boiling.Film boiling occurs when the surface temperature exceeds the“eidenfrost temperature”,which is,for example,about 275℃ for water boiling under atmos-pheric pressure,much higher than the corresponding saturation temperature of boiling liquid.

关键词： flow fill boiling heat transfer subcooled liquid phenomenological model semi-empirical theory

modeling Diesel Engine Flow Processes For Performance and Emissions

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Modeling Diesel Engine Flow Processes For Performance and Em...