Thermo-Hydro-Mechanical Simulation of a Heating and Hydration Experimental Study (the China-Mock-Up) in GMZ Bentonite

2011 ◽  
Author(s):  
L. Chen ◽  
J. Wang ◽  
Y. M. Liu ◽  
F. Collin ◽  
J. L. Xie
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Qualitative Analysis ◽  
Mechanical Behavior ◽  
Liquid Water ◽  
Numerical Study ◽  
Experimental Investigations ◽  
Gmz Bentonite ◽  
Present Stage ◽  
Proposed Model

This paper presents a numerical study of the China-Mock-up test, with the purpose of evaluating the performance of Gaomiaozi (GMZ) bentonite under coupled thermo-hydro-mechanical (THM) conditions. In the paper, the basic THM characteristics of GMZ bentonite are presented first. The formulation of coupling heat, moisture (liquid water and water vapour) and air transfer is given. The model of Alonso-Gens (1) is incorporated to reproduce the mechanical behavior of the GMZ bentonite under unsaturated conditions. With the parameters determined from experimental investigations, numerical simulations of the China-Mock-up test are carried out using the code of LAGAMINE. Owing to the lack of experimental data at present stage, a qualitative analysis of the predictive results is realized. The results suggest that the proposed model is able to reproduce the mechanical behavior of GMZ bentonite, and to predict moisture and air motions under thermal solicitations.

Mathematical Modelling of Materials Behavior Under Creep Conditions

2001 ◽  
Vol 54 (2) ◽  
pp. 107-132 ◽  
Author(s):  
J. Betten
Keyword(s):  
Experimental Data ◽  
Mathematical Modelling ◽  
Mechanical Behavior ◽  
Review Article ◽  
Material Behavior ◽  
Experimental Investigations ◽  
Rational Basis ◽  
Complex Material ◽  
Interpolation Methods ◽  
Materials Behavior

This article will provide a short survey of some recent advances in the mathematical modelling of materials behavior under creep conditions. The mechanical behavior of anisotropic solids requires a suitable mathematical modelling. The properties of tensor functions with several argument tensors constitute a rational basis for a consistent mathematical modelling of complex material behavior. This article presents certain principles, methods, and recent successful applications of tensor functions in creep mechanics. The rules for specifying irreducible sets of tensor invariants and tensor generators for material tensors of rank two and four are also discussed. Furthermore, it is very important that the scalar coefficients in constitutive and evolutional equations are determined as functions of the integrity basis and experimental data. It is explained in detail that these coefficients can be determined by using tensorial interpolation methods. Some examples for practical use are discussed. Finally, we have carried out our own experiments to examine the validity of the mathematical modelling. Furthermore, an overview of some important experimental investigations in creep mechanics of other scientists has been provided. There are 243 references cited in this review article.

scholarly journals Experimental Study and Modeling of Fouling in Immersed Membrane Bioreactor Operating in Constant Pressure Filtration

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Mostafa Hosseinzadeh ◽  
Mohammad Reza Mehrnia ◽  
Navid Mostoufi
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Constant Pressure ◽  
Initial Rate ◽  
Membrane Surface ◽  
Air Velocity ◽  
Pressure Filtration ◽  
Filtration Resistance ◽  
Proposed Model ◽  
Cake Formation

A new mathematical model is proposed based on filtration mechanisms for the prediction of fouling in airlift immersed membrane bioreactors (iMBRs). The cake formation on the membrane surface through constant pressure filtration process in the iMBR was explained by a proposed cake filtration mechanism which assumes that no particle enters the pores when forming the cake layer on the membrane surface. The cake porosity reduction due to diffusion of particles was described by an intermediate blocking mechanism. Experimental study of fouling was also performed in a lab-scale airlift flat-sheet iMBR operating at constant vacuum. The mixed liquor suspended solid (MLSS) concentration was changed within the range of 5000 to 15000 mg/L, while the superficial air velocity was varied between 32 and 128 m3/m2/h. The presented model includes two parameters, that is, ultimate filtration resistance and initial rate of cake formation. The effect of the MLSS concentration and superficial air velocity on the parameters of the proposed model was studied. The results obtained from the model demonstrated that the ultimate filtration resistance and the initial rate of cake formation are more sensitive to the aeration rate at lower superficial velocities. It was also shown that the ultimate filtration resistance has a linear relation with MLSS concentration. A good agreement exists between the results of the model and the experimental data. The proposed model also showed a better compatibility with the experimental data compared to other fouling models available in the literature.

scholarly journals Experimental study of the operation of the bolt joint of a bearerwith a column in precast-monolithic ceiling

Vestnik MGSU ◽  
2015 ◽  
pp. 27-35
Author(s):  
Aleksandr Aleksandrovich Koyankin ◽  
Valeriy Mikhaylovich Mitasov
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Crack Resistance ◽  
Strain State ◽  
Structural Reliability ◽  
Objective Assessment ◽  
Wide Distribution ◽  
Experimental Investigations ◽  
Building Structures ◽  
The Given

Precast-monolithic construction is becoming an increasingly popular form of housing. The wide distribution of this type of construction is explained by the possibility to successfully combine the advantages of precast and monolithic construction, at the same time reducing their disadvantages. Though there is a significant lack of data, including experimental data, for objective assessment of the stress-strain state of precast-monolithic floor structures. In order to investigate the structural reliability of the bolt joint of a bearer with a column in a precast-monolithic building a series of experimental investigations were carried out in the laboratory of testing the building structures of the Siberian Federal University.One of the main conclusions is that the bolt joint of a bearer with a column is characterized by sufficient rigidity, crack resistance and bearing capacity. The results of the given work have proved the data obtained in previously conducted investigations on a fragment of a precast-monolithic ceiling.

Numerical and experimental study on knocking combustion in turbocharged direct-injection engines for a wide range of operating conditions

2021 ◽  
pp. 146808742110601
Author(s):  
Magnus Kircher ◽  
Emmeram Meindl ◽  
Christian Hasse
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Numerical Study ◽  
Direct Injection ◽  
Operating Conditions ◽  
Auto Ignition ◽  
Spark Timing ◽  
Crank Angle ◽  
Wide Range ◽  
The Mean

A combined experimental and numerical study is conducted on knocking combustion in turbocharged direct-injection spark-ignition engines. The experimental study is based on parameter variations in the intake-manifold temperature and pressure, as well as the air-fuel equivalence ratio. The transition between knocking and non-knocking operating conditions is studied by conducting a spark timing sweep for each operating parameter. By correlating combustion and global knock quantities, the global knock trends of the mean cycles are identified. Further insight is gained by a detailed analysis based on single cycles. The extensive experimental data is then used as an input to support numerical investigations. Based on 0D knock modeling, the global knock trends are investigated for all operation points. Taking into consideration the influence of nitric oxide on auto-ignition significantly improves the knock model prediction. Additionally, the origin of the observed cyclic variability of knock is investigated. The crank angle at knock onset in 1000 consecutive single cycles is determined using a multi-cycle 0D knock simulation based on detailed single-cycle experimental data. The overall trend is captured well by the simulation, while fluctuations are underpredicted. As one potential reason for the remaining differences of the 0D model predictions local phenomena are investigated. Therefore, 3D CFD simulations of selected operating points are performed to explore local inhomogeneities in the mixture fraction and temperature. The previously developed generalized Knock Integral Method (gKIM), which considers the detailed kinetics and turbulence-chemistry interaction of an ignition progress variable, is improved and applied. The determined influence of spark timing on the mean crank angle at knock onset agrees well with experimental data. In addition, spatially resolved information on the expected position of auto-ignition is analyzed to investigate causes of knocking combustion.

scholarly journals Numerical study of mixing and heat transfer of SRF particles in a bubbling fluidized bed

2019 ◽  
Vol 142 (2) ◽  
pp. 1087-1096
Author(s):  
Mohamed Sobhi Alagha ◽  
Botond Szucs ◽  
Pal Szentannai
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Fluidized Bed ◽  
Present Model ◽  
Numerical Study ◽  
Sand Particle ◽  
Particle Sizes ◽  
Proposed Model ◽  
Bubbling Fluidized Bed ◽  
Good Agreement

AbstractIn this article, numerical investigations on mixing and heat transfer of solid refused fuel (SRF) particles in a bubbling fluidized bed are carried out. The numerical model is based on the Eulerian–Eulerian approach with empirical submodels representing gas–solid and solid–solid interactions. The model is verified by experimental data from the literature. The experimental data include SRF vertical distribution in SRF–sand mixtures of different sand particle sizes ($$d_{\mathrm{pm}} = 654,810$$ d pm = 654 , 810 and 1110 $$\upmu$$ μ m) at different fluidization velocities ($$u/u_{\mathrm{mf}} = 1.2$$ u / u mf = 1.2 –2.0). We proposed magnification of drag force exerted by the gas on SRF particles based on Haider and Levenspiel (Powder Technol 58(1):63–70, 1989) drag coefficient. The proposed model shows good agreement with the experimental data at high fluidization velocities ( $$u/u_{\mathrm{mf}} = 1.5$$ u / u mf = 1.5 –2.0) and poor predictions at low fluidization velocities ($$u/u_{\mathrm{mf}} = 1.2$$ u / u mf = 1.2 –1.5). Heat transfer results showed that the present model is valid and gives good agreement with the experimental data of wall–bed heat transfer coefficient.

Numerical Study on Turbulence Modification in Particle-Laden Pipe Flows

2011 ◽  
Vol 130-134 ◽  
pp. 3603-3606
Author(s):  
Fu Sheng Yan ◽  
Wei Jun Zhang ◽  
Ru Quan Liang
Keyword(s):  
Experimental Data ◽  
Turbulent Flows ◽  
Pipe Flow ◽  
Numerical Study ◽  
Vertical Pipe ◽  
Pipe Flows ◽  
Dilute Gas ◽  
Turbulence Modification ◽  
Proposed Model ◽  
Simulation Results

This investigation deals with the study on the processes involved in the phenomenon about turbulence modification in dilute gas-particle turbulent flows. The proposed model, along with other selected turbulence modification models from the literature, is used to simulate a particle-laden vertical pipe flow. The simulation results show that the new model provides improved predictions of the experimental data.

scholarly journals Experimental and Numerical Study of Bead Welding Behavior of HDPE Pipe Under Uniaxial Loading

2019 ◽  
Vol 23 (1) ◽  
pp. 183-191
Author(s):  
Azzeddine Belaziz ◽  
Mohamed Mazari
Keyword(s):  
Experimental Study ◽  
Mechanical Behavior ◽  
High Density Polyethylene ◽  
Numerical Study ◽  
Base Material ◽  
Welding Process ◽  
Experimental Tests ◽  
Experimental Results ◽  
Butt Welding ◽  
Hdpe Pipe

Abstract The present paper is devoted to the experimental study of the mechanical behavior of high-density polyethylene structure subjected to traction and welded by means of butt-welding process. We were based ourselves on experimental tests which have been carried out to characterize the material studied, introducing the ductility or fragility of the bead welded section, and understood the effect of crosshead speeds on the mechanical behavior of the weld bead. The experimental results of the welded specimens are compared with those corresponding to the base material. In this study, two crosshead speeds of 10 and 50 mm/min were applied to make the comparison.

EXPERIMENTAL STUDY OF THE KINEMATIC PARAMETERS OF MOVEMENT OF CARS FORCED IDLE MOTION

2018 ◽  
pp. 52-57
Author(s):  
Ivelin Kostov
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Experimental Research ◽  
Kinematic Parameters ◽  
Research Results ◽  
Software Product

In the work brought some experimental data of kinematic parameters of movement of cars forced idle, as the software product was used to diagnose 900 ATS, which recorded kinematic parameters of vehicle. On the basis of the conducted experimental research results are shown tabulated and analysed.

Dual Release Model to Evaluate Dissolution Profiles from Swellable Drug Polyelectrolyte Matrices

2020 ◽  
Vol 17 (6) ◽  
pp. 511-522 ◽  
Author(s):  
Alicia Graciela Cid ◽  
María Verónica Ramírez-Rigo ◽  
María Celeste Palena ◽  
Elio Emilio Gonzo ◽  
Alvaro Federico Jimenez-Kairuz ◽  
...  
Keyword(s):  
Experimental Data ◽  
Drug Release ◽  
Inflection Point ◽  
Release Profile ◽  
Experimental Point ◽  
Extended Model ◽  
Release Process ◽  
Proposed Model ◽  
Dual Release ◽  
Release Model

Background: Mathematical modeling in modified drug release is an important tool that allows predicting the release rate of drugs in their surrounding environment and elucidates the transport mechanisms involved in the process. Objective: The aim of this work was to develop a mathematical model that allows evaluating the release profile of drugs from polymeric carriers in which the swelling phenomenon is present. Methods: Swellable matrices based on ionic complexes of alginic acid or carboxymethylcellulose with ciprofloxacin were prepared and the effect of adding the polymer sodium salt on the swelling process and the drug release was evaluated. Experimental data from the ciprofloxacin release profiles were mathematically adjusted, considering the mechanisms involved in each stage of the release process. Results: A proposed model, named “Dual Release” model, was able to properly fit the experimental data of matrices presenting the swelling phenomenon, characterized by an inflection point in their release profile. This entails applying the extended model of Korsmeyer-Peppas to estimate the percentage of drug released from the first experimental point up to the inflection point and then a model called Lumped until the final time, allowing to adequately represent the complete range of the drug release profile. Different parameters of pharmaceutical relevance were calculated using the proposed model to compare the profiles of the studied matrices. Conclusion: The “Dual Release” model proposed in this article can be used to predict the behavior of complex systems in which different mechanisms are involved in the release process.

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