Formation of Vortex Structures in the Prenozzle Space of an Engine with a Vectorable Thrust Nozzle

Abstract

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...

Numerical Simulation of Intrachamber Processes in the Power Plant

“…Mathematical modeling of intrachamber processes in a power plant is considered in [14][15][16][17][18][19][20][21]. However, they lack practically useful criteria equations.…”

“…However, they lack practically useful criteria equations. In [13][14][15][16][17][18][19][20], it is shown that the spatial flow in the CC and PV is characterized by the presence of vortex structures. Heat exchange processes in different layouts of PP are studied in [15][16][17], but they do not provide criteria relations, and there is no assessment of the applicability for equations [1][2][3][4][5][6][7].…”

“…In [13][14][15][16][17][18][19][20], it is shown that the spatial flow in the CC and PV is characterized by the presence of vortex structures. Heat exchange processes in different layouts of PP are studied in [15][16][17], but they do not provide criteria relations, and there is no assessment of the applicability for equations [1][2][3][4][5][6][7]. The study of heat transfer in the CC PP in the one-dimensional statement is carried out in [14], but there is no assessment of the adequacy of the obtained results as applied to spatial objects.…”

“…The application of mathematical modeling methods to study the heat exchange processes in individual structures of PP is considered in [10][11][12][13][14][15][16][17][18][19][20]. In [10][11][12][13][14][15][18][19][20]22], the features of the flow structure in the pre-nozzle volume of CC PP with a recessed nozzle are shown, but there are no assessments of heat exchange near the surface of the recessed nozzle.…”

Fluid Dynamics of Thrust Vectorable Submerged Nozzle

“…For technological reasons, the subsonic part of the rotary nozzle is usually submerged into the combustion chamber (submerged nozzle). The immersion of the nozzle inside the pre-nozzle volume reduces the longitudinal size of the rocket, but generates a number of problems associated with the high-temperature flow of combustion products [7][8][9]. In a submerged nozzle, the impact of a two-phase flow of combustion products hits the frontal surface of the nozzle inlet, which poses the problem of organizing the flow in this area, excluding increased thermal and erosion effects [2].…”