An approximate calculation of the isentrope of a gas in chemical equilibrium

Fomin, P. A.; Trotsyuk, A. V.

doi:10.1007/bf00789366

Cited by 21 publications

(9 citation statements)

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“…Note that Eq. (5) with α = 0 transforms to the corresponding formula for the gas in chemical equilibrium [33]. As was noted in [36], this formula allows one to calculate the parameters of the two-phase mixture with an error within several percent if the above-made assumption are valid.…”

Section: Detonation-wave Parameters and Cell Size In Gas Mixtures Witmentioning

confidence: 97%

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Effect of chemically inert particles on parameters and suppression of detonation in gases

Fomin

Chen

2009

Combust Explos Shock Waves

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An algorithm for calculating the parameters of a steady one-dimensional detonation wave in mixtures of a gas with chemically inert particles and estimating the detonation-cell size in such mixtures is proposed. The calculated detonation parameters and cell size in stoichiometric hydrogen-oxygen mixtures with W, Al 2 O 3 , and SiO 2 particles are used to analyze the method of suppression of multifront gas detonation by injecting chemically inert particles ahead of the leading wave front. The ratio between the channel diameter and the detonation-cell size is used to estimate the limit of heterogeneous detonation in the mixtures considered. The minimum mass of particles and the characteristic cloud size necessary for detonation suppression are calculated. The effect of thermodynamic parameters of particles on the detonation suppression process is analyzed for the first time. Particles with a high specific heat and (if melting occurs) a high phase-transition heat are found to exert the most pronounced effect.

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Section: Detonation-wave Parameters and Cell Size In Gas Mixtures Witmentioning

confidence: 97%

“…The specific internal energy and the molar mass μ of the gas in the state of chemical equilibrium are calculated by the model described in [32,33]:…”

Section: Detonation-wave Parameters and Cell Size In Gas Mixtures Witmentioning

confidence: 99%

Effect of chemically inert particles on parameters and suppression of detonation in gases

Fomin

Chen

2009

Combust Explos Shock Waves

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“…The model of chemical equilibrium of gaseous mixtures [18][19][20][21] used in the present chapter makes it possible to calculate thermodynamic parameters with an error no higher than several percent. Therefore, the model of chemical equilibrium in a mixture of a gas with chemically inert particles presented in this work has nearly the same accuracy if the assumptions forming the basis of this model correspond to reality.…”

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“…It is noteworthy that if α is zero, formula (5) is transformed into the corresponding formula presented in [20,21] for the gas in a chemical-equilibrium state.…”

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Parameters, limits, attenuation, and suppression of detonation in mixtures of an explosive gas with chemically inert microparticles

Федоров

Fomin

Тропин

et al. 2012

J Eng Phys Thermophy

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UDC 534.222Chapman-Jouguet parameters and the cell size of a detonation wave in mixtures of an explosive gas with chemically inert particles have been calculated. The algorithm of calculation of the minimum mass and characteristic dimension of a particle cloud ensuring successful suppression of detonation in the gas has been proposed. The calculation results are in good agreement with the available experimental data. The influence of the initial composition of the gas on the efficiency of suppression of the detonation wave has been analyzed. The issue of the dependence of the concentration limits of detonation on the mass fraction of particles has been investigated. It has been established that the increase in the concentration of the condensed phase leads to a narrowing of the existence domain of detonation and that the propagation of the detonation wave becomes impossible when the concentration of the particles is fairly high.Introduction. Injection of chemically inert particles is an efficient method of control of detonation processes in gaseous mixtures. The theory of propagation and suppression of a detonation wave (DW) in gases with chemically inert particles is far from completion. It is only the influence of the size, density, and concentration of the particles of the wave parameters that has theoretically been investigated until recently [1][2][3][4][5][6][7][8][9][10][11][12]. Theoretical modeling was mainly one-dimensional. Two-dimensional modeling of detonation in mixtures of a gas with particles has been carried out in [9,11,12]. According to the results of theoretical investigations, an increase in the concentration of the condensed phase and a decrease in the particle size and the density of the particle material improve the efficiency of suppression of the wave by chemically inert particles. These results correlate with available experimental data.At the same time, the minimum total mass of the condensed phase and the spatial length of a particle cloud, which cause wave suppression, have not been calculated, except for [13]. The influence of the mixture's thermodynamic parameters (in particular, heat capacity, temperature, and melting heat) has not been analyzed. The issue of the criterion of successful suppression of a DW in reactive gases with particles remained open, too.In [14], we proposed an algorithm for the calculation of the parameters of a Chapman-Jouguet wave in mixtures of a gas with chemically inert microparticles and the method of evaluation of the relative size of a detonation cell. By analogy with gaseous detonation, we proposed the criterion (based on a comparison of the channel diameter and the cell size) for the limit of multifront detonation in such heterogeneous media. We calculated the minimum mass of the particles and the characteristic dimension of the cloud that are necessary for suppressing detonation. We were the first to analyze the influence of the thermodynamic parameters of the particles on the process of detonation suppression. Calculations of the DW velocity as a f...

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Dynamics of a single bubble in a liquid in the presence of chemical reactions and interphase heat and mass exchange

Kedrinskii¹,

Fomin²,

Taratuta³

1999

J Appl Mech Tech Phys

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As is known [1, 2], detonation of bubble media can be related to heat-and mass-transfer processes, whose rate increase markedly with development of instability of the bubble surface, which leads to formation of microdrops in them [3]. Evaporation of microdrops has a significant effect on the gas-phase chemical reaction in the bubble. Moreover, in a system where the fuel and oxidizer are in different phases [1], formation of a detonation wave is impossible without interphase heat and mass exchange, which leads to formation of a chemically reactive mixture." The detonation regime of the reactions in bubbles was studied in [4].In the present work, as the first stage in the development of an adequate model for bubble detonation in such media, we consider the influence of inert and chemically reactive additives in the active gas mixture of a bubble on bubble dynamics and explosive process, and reaction propagation during formation of the mixture.The dependences of the parameters of a single bubble on the time of injection tinj, the initial dimensions of microdrops Do, and the mass of evaporated liquid Mr~ are analyzed in the case of instantaneous evaporation of microdrops and with allowance for evaporation dynamics.Bubble dynamics is described by the Rayleigh equation under the assumption that the bubble retains its spherical shape, and the gas is ideal: 3 i ~fl" + 5 ~ = P -P~o.Here ~ = R/Ro is the dimensionless radius of the bubble, fl~ and/~" are the derivatives of fl with respect to dimensionless time r = (~L/Ro)t (PL is the liquid density and t is time), R and R0 are the current the and initial radii of the bubble, P~o is the external pressure referred to the initial pressure/9o, and P is given by the following relation, which takes into account losses in acoustic radiation of the bubble:

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An approximate calculation of the isentrope of a gas in chemical equilibrium

Cited by 21 publications

References 1 publication

Effect of chemically inert particles on parameters and suppression of detonation in gases

Effect of chemically inert particles on parameters and suppression of detonation in gases

Parameters, limits, attenuation, and suppression of detonation in mixtures of an explosive gas with chemically inert microparticles

Dynamics of a single bubble in a liquid in the presence of chemical reactions and interphase heat and mass exchange

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