Direct experimental impulse measurements for detonations and deflagrations

Cooper, Marcia A.; Jackson, Steve; Austin, Joanna; Wintenberger, E.; Shepherd, J. E.

doi:10.2514/6.2001-3812

Cited by 47 publications

(41 citation statements)

References 8 publications

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“…[4,35,36] and Refs. [37,38] for what concerns numerical studies and experimental results, respectively. Moreover, the response of the steady solution to the simulations widely reflects the resources incorporated in the mathematical model, especially those resources defining the chemical kinetics framework.…”

Section: Boundary Conditionsmentioning

confidence: 99%

Equilibrium and stability properties of detonation waves in the hydrodynamic limit of a kinetic model

Marques¹,

Soares²,

Bianchi³

et al. 2015

J. Phys. A: Math. Theor.

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A shock wave structure problem, as the one which can be formulated for the planar detonation wave, is analyzed here for a binary mixture of ideal gases undergoing the symmetric reaction A 1 + A 1 A 2 + A 2 . The problem is studied at the hydrodynamic Euler limit of a kinetic model of the reactive Boltzmann equation. The chemical rate law is deduced in this frame with a second-order reaction rate, in a chemical regime such that the gas flow is not far away from the chemical equilibrium. The caloric and the thermal equations of state for the specific internal energy and temperature are employed to close the system of the balance laws. With respect to other approaches known in the kinetic literature for detonation problems with a reversible reaction, this paper is addressed to improve some aspects of the wave solution. Within the mathematical analysis of the detonation model, the equation of the equilibrium Hugoniot curve of the final states is explicitly derived for the first time and used to define the correct location of the equilibrium Chapman-Jouguet point in the Hugoniot diagram. The parametric space is widened to investigate the response of the detonation solution to the activation energy of the chemical reaction. At last, the mathematical formulation of the linear stability problem is given for the wave detonation structure via a normal-mode approach, when bidimensional disturbances perturb the steady solution. The stability equations with their boundary conditions and the radiation condition of the considered modeling are explicitly derived for small transversal deviations of the shock wave location. The paper shows how a second-order chemical kinetics description, derived at the microscopic level, and an analytic deduction of the equilibrium Hugoniot curve, lead to an accurate picture of the steady detonation with reversible reaction, as well as to a proper bidimensional linear stability analysis.

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Section: Boundary Conditionsmentioning

confidence: 99%

Equilibrium and stability properties of detonation waves in the hydrodynamic limit of a kinetic model

Marques¹,

Soares²,

Bianchi³

et al. 2015

J. Phys. A: Math. Theor.

View full text Add to dashboard Cite

show abstract

“…They used a ballistic pendulum to measure the impulse from the tube's maximum horizontal displacement. Cooper et al 3 and Falempin et al 4 also used a ballistic pendulum to measure single-cycle impulse values of ethylene-oxygen mixtures in detonation tubes with attached extensions having a constant cylindrical cross section and also in extensions of varying dimensions. Cooper et al 3 extended their tests to study the effect of diluent amount.…”

mentioning

confidence: 99%

The Effect of Nozzles and Extensions on Detonation Tube Performance

Cooper¹,

Shepherd²

2002

38th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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The effect of nozzles on the impulse obtained from a detonation tube has been the focus of many experimental and numerical studies. We develop a partial-fill model to predict the impulse obtained from a detonation tube containing an extension (considered a partially-filled detonation tube). The experimental impulse values are found to be linearly dependent on the fraction of the tube volume filled with the explosive mixture. Data from numerical simulations were used to predict the impulse for small fill fractions not experimentally tested. The analytical Gurney model provides a method for correcting the experimental data for the tamping provided by diaphragms of a finite mass. A thermodynamic cycle analysis of a detonation is conducted to evaluate the fraction of stored chemical energy in an explosive mixture that can be converted into mechanical work. It is found that approximately 46%-64% of the ideal work from a detonation can be converted into impulse. This fraction increases with increasing nitrogn dilution. The partial-fill model is validated with multi-cycle experimental data and numerical simulations. We compare the partial-fill model with experimental data of diverging nozzles. Ideal ideal detonation efficiency calculated from Jacobs cycle Isp detonation efficiency based on predicted specific impulse ρ 1 density of reactants ρ air density of air mixture in extension

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“…Also, orifice plates with different sizes and geometries with blockage ratio between 0.54 and 0.98 were analyzed for the effect. Copper et al [9] analyzed detonation to deflagration in the closed tube using ballistic pendulum arrangement. The result was with 15% error when compared with the experimental result for internal obstacles on DDT transition.…”

Section: Introductionmentioning

confidence: 99%

Computational Study on Effect of Obstacles in Pulse Detonation Engine

Tripathi¹,

Pandey²,

Randive³

2018

IJET

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Deflagration to Detonation transition is an important factor in the operation of pulse detonation engine which is basically working on the constant volume cycle. Insertion of obstacles decreases the DDT length. Hydrogen and the oxygen-enriched air was used as fuel and oxidizer respectively. The Purge gas is not required used. K-ԑ turbulence model is being used for the simulation and for combustion species transport model is being used. Effect of blockage ratio and obstacle spacing is also discussed. A blockage ratio of 0.5 is considered for the Shchelkin spiral. Temperature profile, flame propagation velocity and average peak pressure variation are discussed. Twodimensional geometry and Shchelkin shape of obstacles are being considered. The comparison is done between straight tube and tube with obstacles. Numerical simulation is done and the results are being compared with those obtained through experimental investigation.

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Direct experimental impulse measurements for detonations and deflagrations

Cited by 47 publications

References 8 publications

Equilibrium and stability properties of detonation waves in the hydrodynamic limit of a kinetic model

Equilibrium and stability properties of detonation waves in the hydrodynamic limit of a kinetic model

The Effect of Nozzles and Extensions on Detonation Tube Performance

Computational Study on Effect of Obstacles in Pulse Detonation Engine

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