Jouguet

The pressure developed by decomposition of acetylene in a closed container depends not only on the initial pressure (or more precisely, density), but also on whether the flame propagates as a deflagration or a detonation, and on the length of the container. For acetylene at room temperature and pressure, the calculated explosion pressure ratio, / initial > deflagration and ca 20 for detonation (at the Chapman-Jouguet plane). At 800 kPa (7.93... 

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. 

A linear relationship between Chapman-Jouguet pressure and density was confirmed for Cyclotol and Octol (Ref 28). Despite the near-equal performance of RDX and HMX at equal densities there appears to be no economical way of making the density of RDX equal to the cast density of HMX. Dinitrobenzene (DNB) has been evaluated as an economical or emergency substitute for TNT but charges prepared with DNB gave somewhat poorer performance than... 

Chapman-Jouguet Pressures of Several Pure and Mixed Explosives , NOL-TR 64-58, AD 603540... 

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-. 

Pressure, Detonation. Detonating condensed expls develop very-high pressures. For most military expls and many of the commercial expls the pressures attained within the expl column do not depend on confinement, provided the column diameter is appreciably larger than the critical diameter of the expl. This confinement-independent pressure associated with a steady detonation is called the Chapman-Jouguet pressure or PCJ... 

The chronology of the most remarkable contributions to combustion in the early stages of its development is as follows. In 1815, Sir Humphry Davy developed the miner s safety lamp. In 1826, Michael Faraday gave a series of lectures and wrote The Chemical History of Candle. In 1855, Robert Bunsen developed his premixed gas burner and measured flame temperatures and flame speed. Francois-Ernest Mallard and Emile Le Chatelier studied flame propagation and proposed the first flame structure theory in 1883. At the same time, the first evidence of detonation was discovered in 1879-1881 by Marcellin Berthelot and Paul Vieille this was immediately confirmed in 1881 by Mallard and Le Chatelier. In 1899-1905, David Chapman and Emile Jouguet developed the theory of deflagration and detonation and calculated the speed of detonation. In 1900, Paul Vieille provided the physical explanation of detonation... 

Jouguet E., Sur la propagation des deflagration dans les mUanges, Compt. Rend., 156 872-875,1913. 

Detonation pressure and temperature of hydrogen-oxygen mixtures starting from 101.3 kPa (1 atm) and 298 K (25°C). Chapman-Jouguet calculations using the Gordon-McBride code. (After Gordon, S. and McBride, B.J.,... 

Chapman und Jouguet gehorten zu den Pionieren auf dem Gebiet der Stoliwellen-Theorie. 

Thermodynamic cycles are a useful way to understand energy release mechanisms. Detonation can be thought of as a cycle that transforms the unreacted explosive into stable product molecules at the Chapman-Jouguet (C-J) state,15 which is simply described as the slowest steady-state shock state that conserves mass, momentum, and energy (see Figure 1). Similarly, the deflagration of a propellant converts the unreacted material into product molecules at constant enthalpy and pressure. The nature of the C-J state and other special thermodynamic states important to energetic materials is determined by the equation of state of the stable detonation products. 

Figure 1 A thermodynamic picture of detonation The unreacted material is compressed by the shock front and reaches the Chapman-Jouguet point. From there adiabatic expansion occurs, which leads to a high-volume state. Finally, detonation products may mix in air and combust.

A purely thermodynamic treatment of detonation ignores the important question of reaction time scales. The finite time scale of reaction leads to strong deviations in detonation velocities from values based on the Chapman-Jouguet theory.16 The kinetics of even simple molecules under high-pressure conditions is not well understood. 

There is no condition by which one can rule out strong detonation however, Chapman stated that in this region only velocities corresponding to J are valid. Jouguet [8] gave the following analysis. 

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. 

In Fig. 30.3, the thermodynamic efficiencies of a constant-pressure Bra3don cycle, a constant-volume Humphery cycle (which approximates a PDE cycle), and a true detonation Chapman-Jouguet (CJ) cycle for a typical hydrocarbon fuel are compared [11]. Though the constant-volume cycle shows substantial efficiency advantage, this zeroth order comparison cannot be taken as the correct quantitative comparison, since PDE operates in a pulsed transient mode. How-... 

Fig. 3.6 Detonation wave formation from shock wave to von Neumann spike, and then to the Chapman-Jouguet point.

---