Numerical simulations of the cellular structure of detonations in liquid nitromethane - Regularity of the cell structure

Journal Article · Mon Sep 01 00:00:00 EDT 1986 · Combust. Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(86)90046-5· OSTI ID:5160110

Guirguis, R; Oran, E S; Kailasanath, K

The detailed structure of planar detonation waves in liquid nitromethane was studied using time-dependent two-dimensional numerical simulations. The walls are assumed to confine heavily the liquid explosive and boundary layer effects are neglected. The solution thus simulates the detonation structure near the center of a wide channel. Chemical decomposition of nitromethane is described by a two-step model composed of an induction time followed by energy release. A simplified equation of state based on the Walsh and Christian technique for condensed phases and the BKW equation of state for gas phases is used. When mixtures of both phases are present, pressure and temperature equilibrium between them is assumed. The simulations show a cellular pattern traced by a system of triple points dividing the detonation front into sections. However, a substructure of weaker triple points also traces out a nonuniform pattern within the main pattern, resulting in an irregular cellular structure. A correlation exists between the regularity of the cellular pattern and both the curvature of the front and the change in induction zone thickness at the triple points. If the induction time is a stronger function of temperature, the weaker triple points disappear and a more regular structure is produced. When the structures are regular, the detonation front is more curved and there is a larger change in induction zone thickness at the triple points. However, the large change in induction zone thickness also leads to the formation of unburned pockets that eventually disturb the symmetry and uniformity of the structure. The authors conclude that the regularity of the cellular pattern is strongly influenced by the temperature-dependence of the induction time.

• Research Organization: Berkeley Research Associates, Springfield, VA 22150
• OSTI ID: 5160110
• Journal Information: Combust. Flame; (United States), Vol. 65:3
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
DETONATION WAVES
MATHEMATICAL MODELS
NITROMETHANE
DETONATIONS
BOUNDARY LAYERS
DECOMPOSITION
EQUATIONS OF STATE
INDUCTION
PHASE STUDIES
PRESSURE DEPENDENCE
SYMMETRY
TEMPERATURE DEPENDENCE
THICKNESS
TIME DEPENDENCE
CHEMICAL EXPLOSIVES
CHEMICAL REACTIONS
DIMENSIONS
EQUATIONS
EXPLOSIVES
LAYERS
NITRO COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
SHOCK WAVES
400800* - Combustion
Pyrolysis
& High-Temperature Chemistry