Experimental Study and Modelling of Combustion Front Velocity in Ti-2B and Ti-C Based Reactant Mixtures

2006 ◽  
Vol 45 ◽  
pp. 2656-2663 ◽  
Author(s):  
M. Martinez Pacheco ◽  
R. Bouma ◽  
O. Arias Cuevas ◽  
Laurens Katgerman
Keyword(s):  
Experimental Study ◽  
Particle Size ◽  
Combustion Synthesis ◽  
Combustion Front ◽  
Theoretical Calculations ◽  
Heat Losses ◽  
Front Velocity ◽  
Experimental Results ◽  
Combustion Reaction ◽  
Analytical Expressions

Experiments on combustion synthesis for the Ti-2B and Ti-C systems diluted with an inert metal are presented. The paper shows the influence of geometry, composition, density and particle size of diluent on the combustion front velocity. A Ti-2B reactant mixture diluted with Al and Cu and a Ti-C reactant mixture diluted with Al are studied. The metallic diluent and its concentration are varied. Besides, each experiment is based on a stack of cylinders with decreasing diameter in order to vary the heat losses. In some experiments the eventual quenching of the combustion reaction has been observed. Furthermore these experimental results are compared with theoretical calculations based on analytical expressions derived for such systems.

Investigation of propagation modes and temperature/velocity variation on unstable combustion synthesis

2002 ◽  
Vol 17 (12) ◽  
pp. 3213-3221 ◽  
Author(s):  
H. P. Li
Keyword(s):  
Activation Energy ◽  
Combustion Synthesis ◽  
Combustion Front ◽  
Propagation Velocity ◽  
Combustion Temperature ◽  
Front Propagation ◽  
Combustion Reaction ◽  
Velocity Variation ◽  
Material Synthesis ◽  
Unstable Combustion

Combustion synthesis/micropyretic synthesis is a technique in which material synthesis is accomplished by the propagation of a combustion front across the sample. In some cases, the combustion front may propagate in an unstable mode where the propagation velocity and combustion temperature of the combustion front are altered periodically. In this study, the processing conditions leading to unstable combustion reaction were first studied theoretically. The boundary temperatures separating stable and unstable reactions were then determined. The numerical analysis showed that the combustion temperature and the propagation velocity changed periodically during unstable combustion. As the combustion reaction became unstable, the average propagation velocity and the oscillatory frequency of front propagation decreased. The products of unstable combustion synthesis possessed the banded structures, implying the occurrence of the unstable oscillatory propagation, as demonstrated experimentally. In this study, high activation energy combustion (Ti + 2B reaction) and low activation energy combustion (Ni + Al reaction) were both chosen to illustrate the effect of unstable combustion. It is the first time the experimental and numerical results were combined to investigate the temperature and propagation velocity variations during unstable combustion.

scholarly journals Experimental Study on the Local Drag of Completion String with Packers in Horizontal Wells

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 657 ◽  
Author(s):  
Qimin Liang ◽  
Bairu Xia ◽  
Baolin Liu ◽  
Zhen Nie ◽  
Baokui Gao
Keyword(s):  
Experimental Study ◽  
Oil And Gas ◽  
Theoretical Calculations ◽  
Horizontal Wells ◽  
Experimental Results ◽  
Economic Losses ◽  
Horizontal Section ◽  
Friction Coefficients ◽  
Oil And Gas Fields ◽  
Gas Fields

The multistage stimulation technology of horizontal wells has brought huge benefits to the development of oil and gas fields. However, the completion string with packers often encounters stuck due to the large drag in the horizontal section, causing huge economic losses. The local drag of the completion string with packers in the horizontal section is very complicated, and it has not been fully understood by theoretical calculations. A local drag experiment is designed to simulate the influence of microsteps and cuttings on the local drag of the completion string with packers in the inclined and horizontal sections. An obvious increase of the local drag of the packer is found at microsteps of the horizontal section, and the local drag is greatly affected by the amount of sand. In addition, the string with packers will vibrate during the tripping process in the deviated section, and the local drag is different when different amounts of sand are in the hole, but the change law is similar. The experimental results show that the friction coefficients of the packers with different materials in the horizontal section vary greatly, resulting in different local drags. It indicates that the local drag of the completion string not only depends on the microsteps and sand quantity in the wellbore, but also on the material difference of the packers. Only if microsteps and cuttings are removed can the completion string be tripped into horizontal wells smoothly.

Mechanistic studies in combustion synthesis of NiAl–TiB2 composites: Effects of gravity

2001 ◽  
Vol 16 (6) ◽  
pp. 1614-1625 ◽  
Author(s):  
Cheryl Lau ◽  
Alexander Mukasyan ◽  
Aleksey Pelekh ◽  
Arvind Varma
Keyword(s):  
Particle Size ◽  
Combustion Synthesis ◽  
Combustion Front ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Liquid Solution ◽  
Matrix Composites ◽  
Mechanistic Studies ◽  
Entire Surface ◽  
Microgravity Conditions

Combustion synthesis (CS) of NiAl-based materials reinforced by TiB2 particles was investigated under both terrestrial and microgravity conditions. The synthesized metal matrix composites (MMC) are characterized by very fine (<1 μm) reinforced particulates, which have strong bonding along their entire surface with matrix (NiAl) and are distributed uniformly in it. It was found that microgravity leads to a decrease in the average TiB2 particle size, while higher volume fraction of NiAl component in the material leads to the formation of coarser reinforced particulates. The mechanism of structure formation of different MMCs during CS was identified by using the quenching technique. For example, it was shown that TiB2 grains appear due to crystallization from the complex (Ni–Al–Ti–B) liquid solution formed in the combustion front. An overall decrease of microstructural transformation rates was observed under microgravity.

scholarly journals Experimental Evaluation of 79 and 300 GHz Radar Performance in Fire Environments

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 439
Author(s):  
Aleksandr Bystrov ◽  
Liam Daniel ◽  
Edward Hoare ◽  
Fatemeh Norouzian ◽  
Mikhail Cherniakov ◽  
...  
Keyword(s):  
Experimental Study ◽  
Water Vapour ◽  
Experimental Evaluation ◽  
Theoretical Calculations ◽  
Video Camera ◽  
Experimental Results ◽  
Radar Signal ◽  
Signal Attenuation ◽  
Millimetre Wave ◽  
In Fire

This paper presents an experimental study of the propagation of mm-wave/low-THz signals in the frequency ranges of 79 and 300 GHz through fire. Radar performance was investigated in various real scenarios, including fire with strong flame, dense smoke and water vapour. A stereo video camera and a LIDAR were used as a comparison with other common types of sensors. The ability of radars to enable the visibility of objects in fire environments was proven. In all scenarios, the radar signal attenuation was measured, and in the case of steam was compared with theoretical calculations. The analysis of the experimental results allows us to conclude that there are good prospects for millimetre wave and Low Terahertz radar in the field of firefighting imaging equipment.

Origins of filter effluent particles: experimental study of particle deposition and detachment

2004 ◽  
Vol 50 (12) ◽  
pp. 215-222
Author(s):  
J. Kim ◽  
J.E. Tobiason
Keyword(s):  
Mathematical Model ◽  
Experimental Study ◽  
Particle Size ◽  
Early Phase ◽  
Particle Deposition ◽  
Laboratory Experiments ◽  
Pore Space ◽  
Experimental Results ◽  
Fluorescent Microspheres ◽  
Filter Bed

This paper investigates the relative roles of particle deposition and detachment in controlling the origin of filter effluent particles. A conceptual mathematical model was developed and laboratory-scale experiments were conducted. Laboratory experiments were performed using three sizes of fluorescent microspheres (FMs), to determine the fraction of filter effluent particles that are filter influent particles that were never removed, as well as the fraction of filter effluent particles that were detached after deposition. Experimental results indicated that particle detachment is significant beginning from the early phase of filtration. FM removal increased with filter run time, depth and particle size. For each size FM at one filter depth, FM removal increased with filter runtime to a maximum due to ripening and then decreased with filter runtime after ripening due to limited pore space remaining in the filter. The fraction of effluent particles that were detached particles increased with particle size and filter bed depth.

Combustion synthesis and characterization of BaTiO3

1995 ◽  
Vol 10 (4) ◽  
pp. 945-952 ◽  
Author(s):  
Zhimin Zhong ◽  
Patrick K. Gallagher
Keyword(s):  
Thermal Analysis ◽  
Aqueous Solution ◽  
Particle Size ◽  
Combustion Synthesis ◽  
High Purity ◽  
Combustion Reaction ◽  
Synthesis And Characterization ◽  
Runaway Reaction ◽  
Spray Dried

An important, somewhat novel procedure for the bulk synthesis of finely divided crystalline BaTiO3 powder has been studied and is applicable to the synthesis of other compounds in the BaO-TiO2 system as well. An aqueous solution of Ba(NO3)2, TiO(NO3)2, and alanine is spray dried. A combustion reaction occurs when heating the product to 300 °C. The reaction converts the spray-dried mixture to BaTiO3. This BaTiO3 powder and its sinterability have been characterized by thermal analysis, XRD, SEM, dielectric, and particle size measurements. The powder resulting from the thermal runaway reaction is finely divided and sinters more readily than the conventionally prepared high purity BaTiO3.

Experimental Study of Particle Size, Sound Velocity, and Resonance Phenomena in a Two-Phase Foam Flow

2001 ◽  
Vol 32 (4-6) ◽  
pp. 5
Author(s):  
A. P. Sevast'yanov ◽  
I. V. An ◽  
S. I. Vainshtein ◽  
Yu. A. Sevast'yanov ◽  
A. V. Sidnev ◽  
...  
Keyword(s):  
Experimental Study ◽  
Particle Size ◽  
Sound Velocity ◽  
Two Phase ◽  
Foam Flow ◽  
Resonance Phenomena

scholarly journals Experimental study of the $ \gamma p \rightarrow K^{0}\Sigma^{+}$, $ \gamma n \rightarrow K^{0} \Lambda$, and $ \gamma n \rightarrow K^{0} \Sigma^{0}$ reactions at the Mainz Microtron

2019 ◽  
Vol 55 (11) ◽  
Author(s):  
C. S. Akondi ◽  
K. Bantawa ◽  
D. M. Manley ◽  
S. Abt ◽  
P. Achenbach ◽  
...  
Keyword(s):  
Experimental Study ◽  
Cross Sections ◽  
Differential Cross ◽  
Legendre Polynomials ◽  
Neutral Kaon ◽  
Experimental Results ◽  
Differential Cross Sections ◽  
Theoretical Predictions ◽  
Photoproduction Reactions ◽  
Insight Into

Abstract.This work measured $ \mathrm{d}\sigma/\mathrm{d}\Omega$dσ/dΩ for neutral kaon photoproduction reactions from threshold up to a c.m. energy of 1855MeV, focussing specifically on the $ \gamma p\rightarrow K^0\Sigma^+$γp→K0Σ+, $ \gamma n\rightarrow K^0\Lambda$γn→K0Λ, and $ \gamma n\rightarrow K^0 \Sigma^0$γn→K0Σ0 reactions. Our results for $ \gamma n\rightarrow K^0 \Sigma^0$γn→K0Σ0 are the first-ever measurements for that reaction. These data will provide insight into the properties of $ N^{\ast}$N* resonances and, in particular, will lead to an improved knowledge about those states that couple only weakly to the $ \pi N$πN channel. Integrated cross sections were extracted by fitting the differential cross sections for each reaction as a series of Legendre polynomials and our results are compared with prior experimental results and theoretical predictions.

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