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The joint international symposia "Gas and Chemical Lasers" (GCL) and "High-Power Lasers" (HPL) are among the regular forums held by SPIE and EOS (The International Society for Optical Engineering and European Optical Society). Usually the national optical society of the host country and corresponding governmental bodies also take part in organization of the current conference. These conferences obtain financial support from European affiliates of research departments of U.S. Air Forces (U.S. Air Force Research Laboratory, Air Force Office of Scientific Research, etc.). P.569-570

Several concepts and scheme solutions are discussed for pressure recovery systems (PRS) in application to specific technical problems. The main features of the diffuser, ejector and steam-gas generator are considered. The specific design schemes for PRS on the base of aviation gas turbine engines were analysed with application to HF(DF)- and COIL-lasers; the workable variants were picked up. Analysis confirmed the opportunity for development of a PRS for a high-power gas chemical laser with modern technologies. The problem of sound suppressing for a stationary and mobile variants of PRS was considered. P. 571-587

Here we consider the problems of a reasonable choice of working parameters for supersonic diffuser (SD) and ejector (EJ), used by the systems of pressure recovery (PRS) of continuous chemical lasers (CCL). The matching condition for SD and EJ parameters was analysed at their merger into a single system. Data presented are mainly attributed to the case of HF(DF) continuous chemical lasers. P. 589-600

The start processes and stationary flow in the diffuser of the laboratory HF/DF laser are investigated on the basis of the computer simulation technology using the non-stationary three-dimensional Navier

The laser-free test methods for the pressure recovery system (PRS) of the HF/DF Continuous Chemical Laser (CCL) are discussed. The method of physical modelling of the HF/DF-CCL flow using a generator of a model gas (GMG) is suggested here. Some scheme and construction solutions as well as a brief technical description of such a system are presented in this paper. Test results for the PRS with GMG are compared with data of actual tests for PRS with DF-CCL. P. 609-617

By means of hydrodynamic and thermodynamic calculations, it is shown that the ignition of a discharge in a closed-flow

By the example of natural flames with energy excess, it is shown that these flames can exist in various systems and combustion regimes. The mere existence of some flames, such as cellular and spin flames, is caused by the excess energy. Mechanisms of energy concentration are also numerous. In addition to heat-transfer processes (conduction, convection, and radiation), energy concentration may be caused by mass-transfer processes, phase transitions, filtration, gas compressibility, etc. Examples of flames with artificial conditions for energy concentration demonstrate a wide range of possible applications of this phenomenon.  P.1-8

Self-drifting combustion spots or flame balls localized in space that have been recently found by numerical simulation of combustion of near<!dash!>limit premixed gases with low Lewis numbers are considered as bifurcations of stationary spherical flame balls.P. 9-18

A two-dimensional steady&-state structure of a film flow of a combustible liquid on a heat-conducting substrate in the case of combustion-wave propagation is considered in the hydrodynamic formulation. The physical mechanism of formation of this structure is analyzed. It is shown that the thermocapillary effect plays an important role. The conclusion is justified that the existence of a two<!dash!>dimensional regime is possible only for rather low values of the temperature gradient on the film surface. A critical condition is obtained, which determines the transition to a three<!dash!>dimensional regime. This condition implies that the flow velocity is equal to the velocity induced by the thermocapillary force. If the temperature gradient is higher than a certain critical value, a zone with a reverse flow should appear, in accordance with the two<!dash!>dimensional model. It is assumed that such a regime cannot exist due to its instability to three<!dash!>dimensional perturbations. Experiments with a liquid film flowing down due to gravity in the presence of an immovable heat source (without the combustion wave) support the conclusion of the transition to a three<!dash!>dimensional regular flow structure if the temperature gradient is rather high. The first part of the paper deals with simulation of the film structure for the critical condition satisfied. The second part deals with generalization of the problem to the case of a movable heat source moving with a constant velocity. This formulation of the problem includes the situation with combustion<!dash!>wave propagation. The mathematical formulation of this problem allows us to assume that the existence of a two<!dash!>dimensional steady<!dash!>state regime in this case is limited by the same critical condition. If the temperature gradient on the film surface is higher than the critical value, the two<!dash!>dimensional steady<!dash!>state solution does not exist. This concept justified in the present work offers a generic explanation of phenomena observed in liquid films in the presence of local heat sources of various natures. P. 19-23

The paper reports results of experimental ignition of litter layers consisting of needles of cedar, pine, and firtree, birch leaves, lichen Cladonia, and moss Pleurozium shreberi. It is established that the moss is ignited faster than the other combustible forest materials. It is shown that with equal moisture contents, the ignition times of needle litter from different trees are identical within the experimental error, and for litter of birch leaves, the ignition time is shorter than that for litter of coniferous trees. This difference is found to be due to differences in the interaction of the radiant flux with litter layers of needles and leaves. Minimum values of the ignition heat pulses for needle and leaf litter layers are estimated for various heatflux densities. These values tend to a minimum for a heatflux density of 0.50.8 MWm². P. 24-29