scholarly journals Numerical Modeling of Combustion and Detonation in Aqueous Foams

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6233
Author(s):  
Alexey Kiverin ◽  
Ivan Yakovenko

Combustible aqueous foams and foamed emulsions represent prospective energy carriers. This paper is devoted to the overview of model assumptions required for numerical simulations of combustion and detonation processes in aqueous foams. The basic mathematical model is proposed and used for the analysis of the combustion development in the wet aqueous foam containing bubbles filled with reactive gas. The numerical results agree with the recent experimental data on combustion and detonation in aqueous foams containing premixed hydrogen–oxygen. The obtained results allowed for distinguishing the mechanisms of flame acceleration, transition to detonation, detonation propagation, and decay.

2015 ◽  
Vol 751 ◽  
pp. 211-216
Author(s):  
Vít Sháněl ◽  
Miroslav Španiel

This paper presents some experimental results of a bullet impact on composite armor together with numerical modeling approaches. The development of light composite sandwiches for ballistic protection is the target of a project in terms of which the research is being conducted. Traditionally, a vehicle ballistic protection is mainly achieved through metal-based armor which is extremely heavy, hence the increasing popularity of composite sandwiches. Numerical simulations allow for a reduction of the number of experiments needed to obtain appropriate design of ballistic protection, but they require verified modeling approaches and proper material data. Therefore, different modelling approaches for both parts of the composite sandwich have been tested and possibilities to adjust these models to experimental data were investigated.


2018 ◽  
Author(s):  
Sean McInerney ◽  
Elliot J Carr ◽  
Matthew J Simpson

AbstractIn this work we consider a recent experimental data set describing heat conduction in living porcine tissues. Understanding this novel data set is important because porcine skin is similar to human skin. Improving our understanding of heat conduction in living skin is relevant to understanding burn injuries, which are common, painful and can require prolonged and expensive treatment. A key feature of skin is that it is layered, with different thermal properties in different layers. Since the experimental data set involves heat conduction in thin living tissues of anesthetised animals, an important experimental constraint is that the temperature within the living tissue is measured at one spatial location within the layered structure. Our aim is to determine whether this data is sufficient to reliably infer the heat conduction parameters in layered skin, and we use a simplified two-layer mathematical model of heat conduction to mimic the generation of experimental data. Using synthetic data generated at one location in the two-layer mathematical model, we explore whether it is possible to infer values of the thermal diffusivity in both layers. After this initial exploration, we then examine how our ability to infer the thermal diffusivities changes when we vary the location at which the experimental data is recorded, as well as considering the situation where we are able to monitor the temperature at two locations within the layered structure. Overall, we find that our ability to parameterise a model of heterogeneous heat conduction with limited experimental data is very sensitive to the location where data is collected. Our modelling results provide guidance about optimal experimental design that could be used to guide future experimental studies.NomenclatureA brief description of all variables used in the document are given in Table 1.Table 1:Variable nomenclature and description.


2019 ◽  
Vol 9 (1) ◽  
pp. 668-673
Author(s):  
Tomasz Jachowicz ◽  
Ivan Gajdos ◽  
Volodymyr Krasinskiy

AbstractThe paper reports the experimental results of a study investigating the effect of different contents of a mineral filler on the rheological properties, p-v-T, of polypropylene. Using the pvT100 apparatus, we measured specific volume under isobaric cooling at different pressures for pure polypropylene and chalk-filled polypropylene (10 wt%, 20 wt% and 30 wt%). Next, we employed computer methods to determine the coefficients of a mathematical model describing the variations in specific volume in a function of temperature and pressure. The model was used in the numerical simulations of injection molding and shrinkage processes.


2002 ◽  
Vol 12 (2) ◽  
pp. 88-104 ◽  
Author(s):  
Evdokia Achilleos ◽  
Georgios C. Georgiou ◽  
Savvas G. Hatzikiriakos

Abstract The objective of this study is mainly to review recent work concerning the numerical modeling of the stick-slip and gross melt fracture polymer extrusion instabilities. Three different mechanisms of instability are discussed: (a) combination of nonlinear slip with compressibility; (b) combination of nonlinear slip with elasticity; and (c) constitutive instabilities. Furthermore, preliminary numerical simulations of the time-dependent, compressible extrudate-swell flow of a Carreau fluid with slip at the wall, using a realistic macroscopic slip equation that is based on experimental data for a high-density polyethylene, are presented.


2002 ◽  
Author(s):  
Pavlos G. Mikellides

Numerical modeling of the Pulsed Inductive Thruster exercising the magnetohydrodynamic code, MACH2 aims to provide bilateral validation of the thruster’s measured performance and the code’s capability of capturing the pertinent physical processes. Computed impulse values demonstrate excellent correlation to the experimental data for a range of energy levels and helium propellant-mass values. The effects of the vacuum tank wall and mass-injection scheme were investigated to show trivial changes in the overall performance.


2012 ◽  
Vol 9 (1) ◽  
pp. 41-46
Author(s):  
R.Kh. Bolotnova ◽  
U.O. Agisheva

Numerical investigations and comparison with experimental data of the shock wave interaction with aqueous foam barrier are conducted, taking into account the change of the foamy veil density on time. The efficiency of damping properties of foam barriers depends on water content is evaluated.


2015 ◽  
Vol 80 (4) ◽  
pp. 549-562 ◽  
Author(s):  
Ivan Tomanovic ◽  
Srdjan Belosevic ◽  
Aleksandar Milicevic ◽  
Dragan Tucakovic

A mathematical model of calcium sorbent reactions for simulation of sulfur dioxide reduction from pulverized coal combustion fl e gasses is developed, implemented within numerical code and validated against available measurements under controlled conditions. The model attempts to closely resemble reactions of calcination, sintering and sulfation, occurring during the sorbent particles motion in the furnace. The sulfation is based on PSSM (Partially Sintered Spheres Model), coupled with simulated particle calcination and sintering. Complex geometry of the particle is taken into account, with the assumption that it consists of spherical grains in contact with each other. Numerical simulations of drop down tube reactors were performed for both CaCO3 and Ca(OH)2 sorbent particles and results were compared with available experimental data from literature. The sorbent reactions model will be further used for simulations of desulfurization reactions in turbulent gas-particle flow under coalcombustion conditions.


1983 ◽  
Vol 105 (4) ◽  
pp. 736-743 ◽  
Author(s):  
A. K. Majumdar ◽  
A. K. Singhal ◽  
H. E. Reilly ◽  
J. A. Bartz

This paper presents several applications of the mathematical model described in Part 1 of the paper. Natural and mechanical draft towers of counterflow and crossflow arrangement have been considered. Predicted thermal performances compare well with the available data from operating towers. The distributions of air velocities, pressure, temperature, moisture fraction, and water temperature have been assessed from the considerations of physical plausibility only, since no experimental data are available for comparison. Some sample parametric computations for a mechanical draft crossflow tower are also presented. The parameters studied are: (a) air travel dimension of fill; (b) aspect ratio of fill; (c) fan power; and (d) atmospheric pressure. The results are self-consistent and demonstrate the applicability of the model as an analysis tool.


2015 ◽  
Vol 11 (2) ◽  
pp. 2972-2978
Author(s):  
Fouad A. Majeed ◽  
Yousif A. Abdul-Hussien

In this study the calculations of the total fusion reaction cross section have been performed for fusion reaction systems 17F + 208Pb and 15C + 232Th which involving halo nuclei by using a semiclassical approach.The semiclassical treatment is comprising the WKB approximation to describe the relative motion between target and projectile nuclei, and Continuum Discretized Coupled Channel (CDCC) method to describe the intrinsic motion for both target and projectile nuclei. For the same of comparsion a full quantum mechanical clacualtions have been preforemd using the (CCFULL) code. Our theorticalrestuls are compared with the full quantum mechaincialcalcuations and with the recent experimental data for the total fusion reaction  checking the stability of the distancesThe coupled channel calculations of the total fusion cross section σfus, and the fusion barrier distribution Dfus. The comparsion with experiment proves that the semiclassiacl approach adopted in the present work reproduce the experimental data better that the full quantal mechanical calcautions. 


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