Pub Date : 2024-04-22DOI: 10.1134/s001050822401012x
E. N. Boyangin, O. V. Lapshin
Abstract
This paper describes the effect of preliminary low-energy mechanical activation of nickel powder on the thermal explosion of a Ni3Al intermetallic compound. Two synthesis methods are considered. The first method requires that a mixture is continuously heated by an external energy source. The second method requires that an external source is turned off upon reaching a certain temperature. It is revealed that low-energy mechanical activation of nickel intensifies the Ni3Al synthesis. With continuous heating, the ignition temperature does not depend on activation time and is equal to the melting point of aluminum. In the case of heating with an external source turned off, preliminary activation of nickel reduces the solid-phase ignition temperature. It is established that nickel activation in a laboratory mill allows one to eliminate its passivation factors.
{"title":"Thermal Explosion in a Powder Mixture of Aluminum with Nickel Preactivated in a Low-Energy Laboratory Mill","authors":"E. N. Boyangin, O. V. Lapshin","doi":"10.1134/s001050822401012x","DOIUrl":"https://doi.org/10.1134/s001050822401012x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>This paper describes the effect of preliminary low-energy mechanical activation of nickel powder on the thermal explosion of a Ni<sub>3</sub>Al intermetallic compound. Two synthesis methods are considered. The first method requires that a mixture is continuously heated by an external energy source. The second method requires that an external source is turned off upon reaching a certain temperature. It is revealed that low-energy mechanical activation of nickel intensifies the Ni<sub>3</sub>Al synthesis. With continuous heating, the ignition temperature does not depend on activation time and is equal to the melting point of aluminum. In the case of heating with an external source turned off, preliminary activation of nickel reduces the solid-phase ignition temperature. It is established that nickel activation in a laboratory mill allows one to eliminate its passivation factors.</p>","PeriodicalId":10509,"journal":{"name":"Combustion, Explosion, and Shock Waves","volume":"218 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140637117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-22DOI: 10.1134/s0010508224010027
V. A. Bunev
Abstract
The combustion of rich mixtures of methanol and hydrogen with air has been studied by experimental and numerical methods. It has been shown that the deviation from Le Chatelier’s principle for the rich flammability limits is due to two factors: flame inhibition by methanol in rich mixtures of hydrogen and the presence of superadiabatic temperatures in rich mixtures of methanol. It has been found that the effect of adding small amounts of hydrogen to rich methanol mixtures is the same as the effect of adding inert nitrogen and carbon dioxide. Numerical simulation has shown that the addition of small amounts of hydrogen to rich methanol mixtures has only a physical effect on the normal flame speed. The addition of H2 affects the occurrence of superadiabatic temperatures in methanol flames in the same way as the addition of inert CO2 and N2.
{"title":"Experimental and Numerical Study of Combustion of Rich Mixtures of Methanol and Hydrogen with Air","authors":"V. A. Bunev","doi":"10.1134/s0010508224010027","DOIUrl":"https://doi.org/10.1134/s0010508224010027","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The combustion of rich mixtures of methanol and hydrogen with air has been studied by experimental and numerical methods. It has been shown that the deviation from Le Chatelier’s principle for the rich flammability limits is due to two factors: flame inhibition by methanol in rich mixtures of hydrogen and the presence of superadiabatic temperatures in rich mixtures of methanol. It has been found that the effect of adding small amounts of hydrogen to rich methanol mixtures is the same as the effect of adding inert nitrogen and carbon dioxide. Numerical simulation has shown that the addition of small amounts of hydrogen to rich methanol mixtures has only a physical effect on the normal flame speed. The addition of H<sub>2</sub> affects the occurrence of superadiabatic temperatures in methanol flames in the same way as the addition of inert CO<sub>2</sub> and N<sub>2</sub>.</p>","PeriodicalId":10509,"journal":{"name":"Combustion, Explosion, and Shock Waves","volume":"123 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140636749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-22DOI: 10.1134/s0010508224010064
A. V. Shcherbakov, V. A. Shcherbakov
Abstract
Mathematical modeling is applied to study the electrothermal explosion conditions of a gasless system surrounded by a dielectric medium. It is shown how conductive heat exchange intensity and Joule heating power affect the formation of dimensionless temperature and concentration profiles, the integral depth of transformation, and the reaction front propagation velocity. The stages of ignition and reaction propagation are divided using a criterion that assumes a conversion depth of 0.99 at any point in the sample. The amount of product formed at the ignition stage is determined. It is demonstrated that a large transformation depth is achieved near critical conditions during ignition on the axis of the sample, thereby causing the displacement of the ignition zone from the axis to the surface of the sample.
{"title":"Simulation of an Electrothermal Explosion of a Gas-Free System. Effect of Conductive Heat Exchange and Joule Heating Power","authors":"A. V. Shcherbakov, V. A. Shcherbakov","doi":"10.1134/s0010508224010064","DOIUrl":"https://doi.org/10.1134/s0010508224010064","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Mathematical modeling is applied to study the electrothermal explosion conditions of a gasless system surrounded by a dielectric medium. It is shown how conductive heat exchange intensity and Joule heating power affect the formation of dimensionless temperature and concentration profiles, the integral depth of transformation, and the reaction front propagation velocity. The stages of ignition and reaction propagation are divided using a criterion that assumes a conversion depth of 0.99 at any point in the sample. The amount of product formed at the ignition stage is determined. It is demonstrated that a large transformation depth is achieved near critical conditions during ignition on the axis of the sample, thereby causing the displacement of the ignition zone from the axis to the surface of the sample.</p>","PeriodicalId":10509,"journal":{"name":"Combustion, Explosion, and Shock Waves","volume":"4 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140637255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-22DOI: 10.1134/s0010508224010143
A. M. Shul’pekov, R. M. Gabbasov, O. K. Lepakova, N. I. Afanas’ev
Abstract
The widespread use of flat electric heaters in equipment and household appliances requires the search for simpler and cheaper technologies for their production. This paper proposes a method for producing an electrically conductive coating (NiAl) and an electrically insulating layer (glass ceramics) in one stage: self-propagating high-temperature synthesis in a thermally coupled (Ni + Al)/(PbO2 + B + Al2O3 + glass) powder mixture. The combustion wave front propagation process is investigated, and the effect of layer thickness along with the ratio of the PbO2 + B + Al2O3 + glass powder mixture components on the wave front propagation velocity and the wave front temperature is described. It is revealed that the wave front of the exothermic process expands when a PbO2 + B mixture is added to the bottom layer. The addition of this mixture makes it possible to reduce the NiAl layer thickness and ensure the formation of a uniform dielectric coating. The phase composition and microstructure of the coating are studied. Optimal ratios are determined for layer thicknesses and the composition of the powder mixture of the layers. The fundamental possibility of forming an electrically conductive and dielectric coating by the method of self-propagating high-temperature synthesis in one stage is shown.
摘要 随着平面电加热器在设备和家用电器中的广泛使用，需要寻求更简单、更廉价的生产技术。本文提出了一种在一个阶段内生产导电涂层（NiAl）和电绝缘层（玻璃陶瓷）的方法：在热耦合（Ni + Al）/（PbO2 + B + Al2O3 + 玻璃）粉末混合物中进行自蔓延高温合成。研究了燃烧波前传播过程，并描述了层厚度以及 PbO2 + B + Al2O3 + 玻璃粉混合物组分比例对波前传播速度和波前温度的影响。结果表明，当在底层加入 PbO2 + B 混合物时，放热过程的波前会扩大。加入这种混合物可以减少 NiAl 层厚度，确保形成均匀的介电涂层。对涂层的相组成和微观结构进行了研究。确定了层厚度和层粉末混合物成分的最佳比例。结果表明，采用自蔓延高温合成法在一个阶段内形成导电和介电涂层的基本可能性。
{"title":"Self-Propagating High Temperature Synthesis in Two-Layer (Ni + Al)/(PbO2 + B + Al2O3 + Glass) Powder Mixtures","authors":"A. M. Shul’pekov, R. M. Gabbasov, O. K. Lepakova, N. I. Afanas’ev","doi":"10.1134/s0010508224010143","DOIUrl":"https://doi.org/10.1134/s0010508224010143","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The widespread use of flat electric heaters in equipment and household appliances requires the search for simpler and cheaper technologies for their production. This paper proposes a method for producing an electrically conductive coating (NiAl) and an electrically insulating layer (glass ceramics) in one stage: self-propagating high-temperature synthesis in a thermally coupled (Ni + Al)/(PbO<sub>2</sub> + B + Al<sub>2</sub>O<sub>3</sub> + glass) powder mixture. The combustion wave front propagation process is investigated, and the effect of layer thickness along with the ratio of the PbO<sub>2</sub> + B + Al<sub>2</sub>O<sub>3</sub> + glass powder mixture components on the wave front propagation velocity and the wave front temperature is described. It is revealed that the wave front of the exothermic process expands when a PbO<sub>2</sub> + B mixture is added to the bottom layer. The addition of this mixture makes it possible to reduce the NiAl layer thickness and ensure the formation of a uniform dielectric coating. The phase composition and microstructure of the coating are studied. Optimal ratios are determined for layer thicknesses and the composition of the powder mixture of the layers. The fundamental possibility of forming an electrically conductive and dielectric coating by the method of self-propagating high-temperature synthesis in one stage is shown.</p>","PeriodicalId":10509,"journal":{"name":"Combustion, Explosion, and Shock Waves","volume":"30 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140636876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-22DOI: 10.1134/s0010508224010052
A. G. Knyazeva
Abstract
There are various methods for the synthesis of composites from mixtures of metal powders forming intermetallic phases and from mixtures of metal and non-metal powders (e.g., carbon or boron). In the 1970s, an approach was proposed to describe combustion and explosion processes with the identification of reactive cells, which from a modern standpoint can be classified as two-level synthesis models. This approach has been actively developed for binary systems, but remained rather conditional. This paper presents an overview of similar models and discusses their development by taking into account accompanying processes (not only diffusion, but also the evolution of the stress–strain state) and modifications for synthesis driven by a laser or electron beam.
{"title":"Two-Level Models of Composite Synthesis: History and Potential","authors":"A. G. Knyazeva","doi":"10.1134/s0010508224010052","DOIUrl":"https://doi.org/10.1134/s0010508224010052","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>There are various methods for the synthesis of composites from mixtures of metal powders forming intermetallic phases and from mixtures of metal and non-metal powders (e.g., carbon or boron). In the 1970s, an approach was proposed to describe combustion and explosion processes with the identification of reactive cells, which from a modern standpoint can be classified as two-level synthesis models. This approach has been actively developed for binary systems, but remained rather conditional. This paper presents an overview of similar models and discusses their development by taking into account accompanying processes (not only diffusion, but also the evolution of the stress–strain state) and modifications for synthesis driven by a laser or electron beam.</p>","PeriodicalId":10509,"journal":{"name":"Combustion, Explosion, and Shock Waves","volume":"48 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140637233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-22DOI: 10.1134/s0010508223060011
A. V. Tupikin, P. K. Tretyakov
Abstract
Results of studying stabilization of a homogeneous hydrogen–air flame on an optical discharge plasma in a high-velocity flow are reported. The main aspect of experiments is providing stable combustion behind the region of laser beam focusing without any mechanical flame holders. The laser radiation parameters are sufficient for creating a quasi-steady plasma in the flow. It is shown that the optical discharge stabilizes the flame front in a wide range of equivalence ratios for flow velocities up to (u = 200) m/s. The laser radiation parameters within the range of their variation from one experiment to another exert a minor effect on the turbulent flame velocity. Flame stabilization behind the optical discharge region has some specific features. An important parameter is heat release due to hydrogen combustion. A dimensionless criterion is derived: the turbulent flame velocity is a linear function of this criterion.
摘要 报告了在高速流动的光学放电等离子体上稳定均质氢气-空气火焰的研究结果。实验的主要方面是在激光束聚焦区域后方提供稳定燃烧，而无需任何机械火焰支架。激光辐射参数足以在气流中形成准稳定等离子体。实验结果表明，在流速高达 (u = 200) m/s 的情况下，光放电可以在很大的等效比范围内稳定火焰前沿。激光辐射参数在不同实验的变化范围内对湍流火焰速度的影响很小。光放电区域后的火焰稳定具有一些特殊的特征。其中一个重要参数是氢燃烧释放的热量。得出了一个无量纲标准：湍流火焰速度是该标准的线性函数。
{"title":"Stabilization of the Hydrogen–Air Flame in a High-Velocity Flow by an Optical Discharge","authors":"A. V. Tupikin, P. K. Tretyakov","doi":"10.1134/s0010508223060011","DOIUrl":"https://doi.org/10.1134/s0010508223060011","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Results of studying stabilization of a homogeneous hydrogen–air flame on an optical discharge plasma in a high-velocity flow are reported. The main aspect of experiments is providing stable combustion behind the region of laser beam focusing without any mechanical flame holders. The laser radiation parameters are sufficient for creating a quasi-steady plasma in the flow. It is shown that the optical discharge stabilizes the flame front in a wide range of equivalence ratios for flow velocities up to <span>(u = 200)</span> m/s. The laser radiation parameters within the range of their variation from one experiment to another exert a minor effect on the turbulent flame velocity. Flame stabilization behind the optical discharge region has some specific features. An important parameter is heat release due to hydrogen combustion. A dimensionless criterion is derived: the turbulent flame velocity is a linear function of this criterion.</p>","PeriodicalId":10509,"journal":{"name":"Combustion, Explosion, and Shock Waves","volume":"137 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139556262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-22DOI: 10.1134/s0010508223060023
D. A. Tropin
Abstract
Injection of inert particles into a stoichiometric hydrogen–air mixture with velocities ranging from 0.1 to 1.0 of the Chapman–Jouguet detonation velocity is calculated. Resultant flow regimes are analyzed. It is found that an increase in the particle temperature leads to ignition of the mixture, while an increase in the particle velocity leads to detonation wave initiation. Critical conditions of detonation initiation in terms of the particle concentration, particle size, and injection velocity are determined. Various possible scenarios of detonation initiation are demonstrated, depending on the particle diameter and concentration, including regimes with multiple initiation sites. Flow charts are constructed in the plane of the parameters “injection velocity–temperature of particles of various sizes."
{"title":"Initiation of Detonation of a Hydrogen–Air Mixture due to Injection of Chemically Inert Solid Particles","authors":"D. A. Tropin","doi":"10.1134/s0010508223060023","DOIUrl":"https://doi.org/10.1134/s0010508223060023","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Injection of inert particles into a stoichiometric hydrogen–air mixture with velocities ranging from 0.1 to 1.0 of the Chapman–Jouguet detonation velocity is calculated. Resultant flow regimes are analyzed. It is found that an increase in the particle temperature leads to ignition of the mixture, while an increase in the particle velocity leads to detonation wave initiation. Critical conditions of detonation initiation in terms of the particle concentration, particle size, and injection velocity are determined. Various possible scenarios of detonation initiation are demonstrated, depending on the particle diameter and concentration, including regimes with multiple initiation sites. Flow charts are constructed in the plane of the parameters “injection velocity–temperature of particles of various sizes.\"</p>","PeriodicalId":10509,"journal":{"name":"Combustion, Explosion, and Shock Waves","volume":"32 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139556132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-22DOI: 10.1134/s0010508223060126
H. Y. Yu, L. Huang, L. M. Wang, X. Zhou
Abstract
An attempt to understand the relation between the burning characteristics and thermal decomposition in a wide range of pressure is made in the present investigation based on solid propellants with ammonium perchlorate as an oxidizer and 3,3-diazomethylepoxybutane and tetrahydrofuran as a fuel binder. The burning rate measurement is carried out in a wide range of pressure: 1.0, 3.0, 7.0, 13.8, 15.0, and 20.0 MPa. The inflection point of the pressure exponent for ammonium perchlorate with and without oxalate and the flame extinguishing point both appear at 13.8 MPa. Various mechanisms of burning rate reduction by the quaternary ammonium salt and oxalate are analyzed by theoretical analysis, thermogravimetric analysis, and differential scanning calorimetry analysis. The burning rate and decomposition of the oxidizer and fuel binder with combustion modifiers and their overall impact on propellant combustion are studied. Due to modifiers, a transition between kinetically controlled combustion and diffusion controlled combustion is found to occur.
{"title":"Burning Characteristics in a Wide Range of Pressure and Thermal Decomposition of AP/PBT Solid Propellants","authors":"H. Y. Yu, L. Huang, L. M. Wang, X. Zhou","doi":"10.1134/s0010508223060126","DOIUrl":"https://doi.org/10.1134/s0010508223060126","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>An attempt to understand the relation between the burning characteristics and thermal decomposition in a wide range of pressure is made in the present investigation based on solid propellants with ammonium perchlorate as an oxidizer and 3,3-diazomethylepoxybutane and tetrahydrofuran as a fuel binder. The burning rate measurement is carried out in a wide range of pressure: 1.0, 3.0, 7.0, 13.8, 15.0, and 20.0 MPa. The inflection point of the pressure exponent for ammonium perchlorate with and without oxalate and the flame extinguishing point both appear at 13.8 MPa. Various mechanisms of burning rate reduction by the quaternary ammonium salt and oxalate are analyzed by theoretical analysis, thermogravimetric analysis, and differential scanning calorimetry analysis. The burning rate and decomposition of the oxidizer and fuel binder with combustion modifiers and their overall impact on propellant combustion are studied. Due to modifiers, a transition between kinetically controlled combustion and diffusion controlled combustion is found to occur.</p>","PeriodicalId":10509,"journal":{"name":"Combustion, Explosion, and Shock Waves","volume":"8 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139556315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-22DOI: 10.1134/s0010508223060151
A. A. Boriskin, A. A. Vasil’ev
Abstract
Formal extrapolation of kinetic data obtained in studying the processes of ignition and low-velocity combustion to supersonic detonation processes most often leads to noticeable underestimation of the critical initiation energy, detonation cell size, and other dimensional parameters of detonation as compared to experimental data. Thus, numerical predictions of the combustible system behavior become less reliable. However, because of the instability-induced non-one-dimensional, nonuniform, and oscillating character of the multifront detonation wave, it is next to impossible to perform reliable experimental measurements of the kinetic parameters of combustible mixtures under the detonation conditions. In the present paper, we propose and approve a method that allows one to get over the above-mentioned limitations by using a technique as close to the detonation conditions as possible. The technique is based on using a decaying shock wave for combustible mixture initiation instead of the classical steady shock wave. Such a decaying wave is formed in the case of reaction failure behind a steadily propagating detonation wave due to its propagation in a channel with sudden expansion (so-called detonation wave diffraction). The basic issues of the technique are discussed, required estimates are made, experimental verification is performed, and results obtained are reported.
{"title":"Excitation of Cylindrical Detonation by a Decaying Shock Wave","authors":"A. A. Boriskin, A. A. Vasil’ev","doi":"10.1134/s0010508223060151","DOIUrl":"https://doi.org/10.1134/s0010508223060151","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Formal extrapolation of kinetic data obtained in studying the processes of ignition and low-velocity combustion to supersonic detonation processes most often leads to noticeable underestimation of the critical initiation energy, detonation cell size, and other dimensional parameters of detonation as compared to experimental data. Thus, numerical predictions of the combustible system behavior become less reliable. However, because of the instability-induced non-one-dimensional, nonuniform, and oscillating character of the multifront detonation wave, it is next to impossible to perform reliable experimental measurements of the kinetic parameters of combustible mixtures under the detonation conditions. In the present paper, we propose and approve a method that allows one to get over the above-mentioned limitations by using a technique as close to the detonation conditions as possible. The technique is based on using a decaying shock wave for combustible mixture initiation instead of the classical steady shock wave. Such a decaying wave is formed in the case of reaction failure behind a steadily propagating detonation wave due to its propagation in a channel with sudden expansion (so-called detonation wave diffraction). The basic issues of the technique are discussed, required estimates are made, experimental verification is performed, and results obtained are reported.</p>","PeriodicalId":10509,"journal":{"name":"Combustion, Explosion, and Shock Waves","volume":"117 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139556263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-22DOI: 10.1134/s0010508223060035
A. A. Chernov, K. V. Toropetsky, O. P. Korobeinichev
Abstract
This paper first presents particle image velocimetry measurements of the chemical time scales versus equivalence ratio and the concentration of the inhibitor trimethyl phosphate for premixed methane–air and dimethyl ether–air flames at atmospheric pressure. Comparison of the experimental results with theoretical estimates based on the Zel’dovich–Barenblatt hypothesis shows their qualitative agreement. Within the accuracy of the experiment, the chemical time scale depends only on the burning rate, rapidly decreasing as it increases. At fuel–air flame speeds close to and above 0.6 m/s, the results of the experiments show the high accuracy of theoretical estimates based on the Zel’dovich–Barenblatt hypothesis.
{"title":"Estimation of the Characteristic Time Scale of a Laminar Flame by Particle Image Velocimetry","authors":"A. A. Chernov, K. V. Toropetsky, O. P. Korobeinichev","doi":"10.1134/s0010508223060035","DOIUrl":"https://doi.org/10.1134/s0010508223060035","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>This paper first presents particle image velocimetry measurements of the chemical time scales versus equivalence ratio and the concentration of the inhibitor trimethyl phosphate for premixed methane–air and dimethyl ether–air flames at atmospheric pressure. Comparison of the experimental results with theoretical estimates based on the Zel’dovich–Barenblatt hypothesis shows their qualitative agreement. Within the accuracy of the experiment, the chemical time scale depends only on the burning rate, rapidly decreasing as it increases. At fuel–air flame speeds close to and above 0.6 m/s, the results of the experiments show the high accuracy of theoretical estimates based on the Zel’dovich–Barenblatt hypothesis.</p>","PeriodicalId":10509,"journal":{"name":"Combustion, Explosion, and Shock Waves","volume":"14 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139556264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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