A numerical simulation of the hydrodynamic effects arising in the process of work of the vectorable thrust nozzle of a solid-propellant rocket engine has been performed. The fi elds of the fl ows of combustion products in the channel of a charge, the prenozzle space, and the nozzle unit were calculated for different angles of vectoring of the nozzle. The distributions of the gasdynamic parameters of the fl ow of combustion products in the prenozzle space, corresponding to their effl ux from the cylindrical and star-shaped channels of charges, were compared. The formation of a vortex fl ow in the neighborhood of the back cover of the nozzle was considered. Introduction.A method of increasing the effi ciency of work of a solid-propellant rocket engine (SPRE) is the use of reliable control members in it [1,2]. Control moments can be created in the structure of an SPRE with the use of a vectorable thrust nozzle vectored by steering gears in accordance with commands from the system controlling a fl ight [3][4][5][6].In modern SPREs, the subsonic section of the vectorable nozzle usually enters into (is submerged in) the combustion chamber for engineering reasons. The submergence of the nozzle of an SPRE into the space upstream of it decreases the longitudinal size of the engine but gives rise to a number of problems associated with the fl ow of high-temperature combustion products around the nozzle. The frontal surface of the input-part of a submerged nozzle is subjected to the action of a twophase fl ow of combustion products, which poses the problem of organization of the fl ow in this region so that this fl ow does not increase the heat and erosion actions on the indicated surface [5]. The gasdynamic situation in the prenozzle space of an SPRE is additionally complicated in the case where charges of different types are used in it [3][4][5].The formation of longitudinal large-scale vortices near the perforated wall of the supersonic section of a nozzle and the possibility of using porous inserts for passive control of the nozzle thrust were considered in the work [7]. It is shown in [8] that large-scale longitudinal pair vortices rotating in the opposite directions arise in the case where subsonic plane and circular jets fl ow around a submerged nozzle. These vortices are formed in the subsonic section of the nozzle and then are transferred to its supersonic section where their intensity decreases due to the widening of the vortex tubes. The formation of the indicated vortices is explained by the curvature of the lines of the fl ow around the subsonic section of the nozzle [7].The work of an SPRE with a vectorable thrust nozzle is associated with a nonsymmetric gas fl ow in the channels of the combustion chamber and the nozzle, due to which there arise a side force and a gasdynamic moment acting on the nozzle. This complex three-dimensional gas fl ow involves spread and drain lines, vortex structures, and separation zones, which leads to the intensifi cation of the heat exchange, the nonsymmetric transfer of the cond...

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A numerical simulation of the gas-dynamic processes in the thrust vectorable nozzle of the solid rocket motor is considered. Construction of a geometric model and a generation of computational mesh, and reconstruction of model and mesh at each time step are discussed. Calculations of the flowfield of combustion products in the pre-nozzle chamber and nozzle block are carried out for various angles of nozzle rotation. The distributions of the gas dynamic quantities in the pre-nozzle volume corresponding to the outflow of the combustion products from the cylindrical channel and star-shaped channel are compared, as well as the solutions of the problem obtained with quasi-stationary and unsteady formulations. The effects of the channel shape on the distribution of flow quantities and formation of a vortical flow structure in the nozzle block are discussed.