Chapman-Jouguet detonation

F. J. Zele2nik and S. Gordon, Ind. Eng. Chem. 60(6), 25 (June 1968) S. Gordon and B. J. McBride, Computer Programfor the Calculation of Complex Chemical Equilibrium Compositions, Pocket Peformance, Incident and Keflected S hocks and Chapman-Jouguet Detonations, NASA SP-273, Lewis Research Center, NTIS N-71-37775, U.S. Department of Commerce, Spriugfield, Va., 1971. 

Gordon, S. and McBride, B. J. 1976. Computer Program for Calculation of Complex Chemical Equilibrium Compositions, Rocket Performance, Incident and Reflected Shocks, and Chapman-Jouguet Detonations. Report SP-273. Interim Revision, Report N78-17724. National Aeronautics and Space Administration, Washington, DC. 

Q (see Vol 7, H38-L), or the related quantity, njTj, where nj is the number of moles of gas under steady (Chapman-Jouguet) detonation conditions and Tj is the detonation temp-. 

Gordon, S., and B. J. McBride. 1971. Computer program for calculation of complex chemical equilibrium compositions, rocket performance, incident and reflected shocks, and Chapman-Jouguet detonations. NASA SP-273. NASA Lewis Research Center. 

The minimum value of is the detonation velocity Up at point J (Chapman-Jouguet detonation velocity). 

Note 4 Calculation of Chapman-Jouguet detonation pressure was done using the equation derived by Cook. It is written by Dunkle... 

Detonation, Predetonation Phase. This is an intermediate phase in the DDT (Deflagration to Detonation Transition) between deflagration (or combustion) and detonation Oppenheim (Ref 3, p 475) describes how during this phase a combustion front is accelerated by a shock process until the shock front is overtaken and a (CJ) Chapman-Jouguet detonation sets in. 

Detonation, Sound Speed Frozen in. Under the heading "Chapman-Jouguet Detonation with Varying Product Composition Frozen Sound Speed , Evans 8t Ablow (Ref 4, pp 150-51) stated the following ... 

Pukhnachev (Ref 26) made a stability analysis of Chapman-Jouguet detonations to clarify the development of spinning detonations. The phenomena leading to them cannot be described by solution of simple hydrodynamic and reaction-kinetic equations for flat detonation fronts. The analysis was based on previous detonation stability analyses by Shchelkin et al with constant supersonic flow postulated along the z-axis at z <0. There is a sharp discontinuity at z=0, followed by the combustion zone. 

It was found also that the front of the reaction zone coincides with the front of self-ignition of gas warmed by the shock wave) 26) V.V. Pukhnachev, ZhPrikl-Mekhan i TekhnFiz No 6, 66-73(1963) (Stability of Chapman-Jouguet detonation)... 

Note 2 Dunkle (Ref 5) remarked that the "ideal or Chapman-Jouguet detonation is a steady-state process, and that the derivation of the Hugoniot equations is based on the process being steady-state, so that the mass velocity. ih (rate of mass flow per unit, area per unit, time) is constant thruout the (one-dimensional) process. 

Explicit Solutions of Equations for Chapman- Jouguet Detonations with Invariant Product Composition... 

Chapman- Jouguet Detonation with Varying Product Composition Frozen Sound Speed... 

Chemistry of Detonations. III. Evaluation of the Simplified Calculational Method for Chapman-Jouguet Detonation Pressures on the Basis of Available... 

Classification Weak deflagration Chapman-Jouguet deflagration Strong deflagration Weak detonation Chapman-Jouguet detonation Strong detonation... 

The process from E to B via A is a process made up of a shock from E to A and a deflagration from A to B. In this case, the high temperatures necessary for initiating the combustion are supplied by the shock rather than by the diffusion processes previously mentioned. This explanation for detonation phenomena was advanced independently by Chapman, and by Jouguet, around 1900. If Q/CPTX is sufficiently large to carry the process to point C, this is a Chapman-Jouguet detonation. As a consequence of the physical means by which detonations are produced, this is the type of detonation usually encountered. 

A Chapman-Jouguet detonation wave may be described as an exothermic supersonic wave that propagates itself at the minimum possible velocity consistent with the conservation laws, whereas a Chapman-Jouguet deflagration is an exothermic subsonic wave that propagates itself at the maximum possible velocity consistent with the conservation laws. 

Detonation. Past investigators have usually considered that a Chapman-Jouguet detonation wave is the only stable detonation wave that normally exists and have expended most of their analytic efforts in describing the change in thermodynamic properties that occurs across this wave. This is accomplished by use of the equations for conser-... 

In the case of an adiabatic process (shock), Q = 0, / = 0, and F = 2. For the case where/ = 1, Equation 13 becomes the equation describing the limiting value of Q/CPTX and hence a Chapman-Jouguet detonation. All the cases of a strong detonation are then described by 1 < F < 2. 

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