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Results of an experimental study of controlled continuous spin detonation of acetylene-air and hydrogen-air mixtures, as well as propane-air-oxygen and kerosene-air-oxygen mixtures in a flow-type cylindrical combustor 30.6 cm in diameter are described. The flow structure and the conditions, properties, and areas of existence of continuous detonation are considered.

A two-dimensional unsteady mathematical model of spin detonation in an annular cylindrical ramjet-type combustor is formulated. The wave dynamics in the combustor filled by a hydrogen-oxygen mixture is studied numerically.

An acetylene-oxygen mixture is burned in two annular chambers 100 mm in diameter in the spin detonation regime with supercritical and subcritical differences of oxygen pressure in the annular slot. By varying the flow rates of components of the mixture, width of the slot for oxidizer injection, point of fuel injection, and initial ambient pressure, the regions of existence and the structure of transverse detonation waves are studied, and the limits of existence of continuous detonation in terms of pressure in the chamber are determined. The losses of the total pressure in the flow in oxygen-injection slots and in fuel-injector orifices are estimated.

A comprehensive numerical and experimental study of continuous spin detonation of a hydrogen-oxygen mixture in annular combustors with the components supplied through injectors is performed. In an annular combustor 4 cm in diameter, burning of a hydrogen-oxygen gas mixture in the regime of continuous spin detonation is obtained. The flow structure is considered for varied flow rates of the components of the mixture and the combustor length and shape. The dynamics of the transverse detonation wave is numerically studied in a two-dimensional unsteady statement of the problem with the geometric parameters of the combustors consistent with experimental ones. A comparison with experiments reveals reasonable agreement in terms of the detonation velocity and pressure in the combustor. The calculated size and shape of detonation fronts are substantially different from the experimental data.

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It is known that during fluid or gas outflow through an orifice in a thin wall or through a short nozzle (L < 2-3d) the minimum cross-sectional area of the jet is always smaller than that of the orifice, because of the perpendicular component of the flow velocity and the nonuniform velocity field. Therefore, the actual fluid-or gas-mass flows are always smaller than those calculated from the cross-sectional area of the orifice (their ratio is known as the discharge coefficient /~). Problems of discharge were first studied theoretically by Saint-Venant, Boussinesq, and Kirchhoff. In Russia N. E. Zhukovskii was first to derive formulas for the contraction coefficient of a liquid jet for discharge through a narrow slot [1]. To date, many investigations have been performed in this line, and the results are best presented in [2, 3]. This paper is devoted to the search for nozzles and their combinations such that the difference between discharge coefficients for the forward/~1 and reverse/~2 directions is maximum. We studied the range of fairly large supercritical pressure drops in nozzles when the outflowing jet was supersonic.Experimental Setup. A schematic diagram of the experimental setup is shown in Fig. 1. A nozzleor a combination of nozzles 1 in a 16-mm-diameter channel 2 were placed in a vessel 3 of volume V = 1.6 liters. The vessel was filled with air (to a pressure of 2.0 MPa) which discharged into the atmosphere through the nozzle upon opening of a quick-acting valve 4. The cross-sectional areas of the valve and of the short pipelines were larger than those of the nozzles by a factor of 10 and greater. The Mr-pressure drop in the vessel was measured by the semiconducting pressure gauge 5 connected in a bridge circuit and recorded by an oscilloscope. Figure 2 shows the tested nozzle shapes: a) is a cylindrical nozzle (for reverse flow it is known as the Borda nozzle) with d = 5.1 mm and L = 15 mm; d = 3.4 mm and L = 9 mm; b) is a conic nozzle with an apex angle of 450 and d = J = 3.4 mm; c) is a profile nozzle with a smooth entry with diameters d = 5.1, 4.65, 4.45, 3.55, and 2.9 mm; d) is a cylindrical nozzle with a flattened exit and a smooth entry; e) is a thin orifice plate with sharp rectangular edges; and f) is a thin orifice plate nozzle with a conic orifice and a sharpened edge.Nozzles with both sharp and blunt edges and also their combinations were tested. To avoid air outflow past the orifices, the outer contours of the nozzle edges were sealed with Teflon rings.Experimental Procedure. The volume of the vessel and the cross-sectional area of the tested nozzles were chosen so that the time t of supersonic air discharge ranged from 0.5 sec to 1.0 sec. Estimations show that, for this time, the characteristic thickness of the thermal air layer near the vessel walls z ~ V~ (a is the thermal diffusivity of air) does not exceed 2-3 ram. Since the process of discharge was analyzed for sufficiently high (at least fivefold) pressure drops in nozzles, the value of z decreases at least twofold and did not exceed...