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Effects of confinement on combustion of TNT explosion products in air

Kuhl A. L., Ferguson R. E., Oppenheim A. K., Sum T-H.J., Reichenbach H., Neuwald P., Kuhl A. L., Ferguson R. E., Oppenheim A.

Archivum Combustionis

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2001

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Vol. 21 nr 1

3-25

EN

A numerical study of turbulent combustion following detonative explosions of TNT in geometrically similar cylinders filled with air reveals that the combustion rate depends significantly on the size of the chamber (confinement). The fluid-dynamic solution provides an insight into the evolution of combustion fields dominated by strong interactions between turbulence and shock waves. Time profiles of fuel consumption, extracted from this solution, demonstrate the dynamic (thermokinetic) features of the system, expressed by the rate of combustion (akin to velocity) and its change (akin to acceleration). Their evolution is described by means of bi-parametric life functions.

2

On the future of combustion technogy

Oppenheim A. K.

Archivum Combustionis

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1999

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Vol. 19 nr 1-4

3-13

EN

In its application to closed system, exemplified prominently by automovite piston engines, combustion technology is the least developed of any in practice today. This leaves an appreciable leeway for improvement - a fact in drastic contrast the widely held belief that internal combustion engines should be abandoned as the major envirinmental menace of our times. The obvious remedy for this paradoxical state of affairs can be derived from the exploitation of the best that modern technology can offer in terms of micro-electronic control associated with MEMS (Micro Electro-Mechanical Systems), whereby the iniection of fuel, its ignition, and mixing with air, are accomplished by turbulent jets. For this purpose the exothermic process of combustion has to be treated as a dynamic system - a task involving proper consideration of the fundamentals of aerodynamics, gasdynamics, thermodynamics, heat transfer and chemical kinetics, with their effects appropriately expressed by modern methods of numerical analysis.

3

Aerothermodynamics of closed combustion system

Oppenheim A. K., Kuhl A. L.

Archivum Combustionis

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1999

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Vol. 19 nr 1-4

15-65

EN

Fundamental concepts of two major subjects involved in the analysis of closed combustion systems: the aerodynamics of turbulence in the physical space (in Part 1), and the thermodynamics of exothermicity in the phase space (in Part 2), are exposed. Of principal significance to the former are the analytical properties of the principal two field elements: the rotational component of turbulence and the irrotational component of exothermicity. Direct implementation of this principle is provided by the random vortex method, illustrated here by solutions of simple two-dimensional, planar cases. Salient features of the latter are expressed in terms of the thermodynamics parameters, the thermostatics and the thermokinetics. Most instrumental for the first is the concept of the Le Chatelier diagram displaying the loci of states of the system components in terms of the relationships between the internal energy and the product of pressure and specific volume. The second provides a solution of the inverse problem in terms of an analytic expression for fuel consumption as a function of the measured pressure profile. The third furnishes a description of the system behavior in terms of its dynamic features: the amount (akin to displacement), rate (akin to velocity) and the change of rate (akin to acceleration).