Numerical Computation of Specific Impulse and Internal Flow Parameters in Solid Fuel Rocket Motors with Two-Phase Сombustion Products

Eulerian --- Lagrangian method was used in the Fluent computational fluid dynamics system to calculate motion of the two-phase combustion products in the solid fuel rocket motor combustion chamber and nozzle. Condensed phase is assumed to consist of spherical particles with the same diameter, which dimensions are not changing along the motion trajectory. Flows with particle diameters of 3, 5, 7, 9, and 11 μm were investigated. Four versions of the engine combustion chamber configuration were examined: with slotted and smooth cylindrical charge channels, each with external and submerged nozzles. Gas flow and particle trajectories were calculated starting from the solid fuel surface and to the nozzle exit. Volumetric fields of particle concentrations, condensed phase velocities and temperatures, as well as turbulence degree in the solid propellant rocket engine flow duct were obtained. Values of particles velocity and temperature lag from the gas phase along the nozzle length were received. Influence of the charge channel shape, degree of the nozzle submersion and of the condensate particles size on the solid propellant rocket engine specific impulse were determined, and losses were estimated in comparison with the case of ideal flow

An investigation of the interaction between a travelling shock wave and a solid rocket motor nozzle

A gasdynamic mechanism has been identified as a potential source of combustion instability in solid-propellant rocket motors (SRMs). This mechanism involves the reinforcement of a reflected shock wave in the nozzle convergence region of an SRM's exhaust nozzle. A shock tube apparatus was developed for the experimental component of this study. Various factors, such as the effect of different nozzle geometries and driven channel pressures, were examined. Also, a model of the shock tube was developed for computational fluid dynamics (CFD) simulations. These simulations were generated for comparison with the experimental results and to provide additional information regarding the nature of the flow behaviour. A gasdynamic mechanism has been identified as a potential source of combustion instability in solid-propellant rocket motors (SRMs). This mechanism involves the reinforcement of a reflected shock wave in the nozzle convergence region of an SRM's exhaust nozzle.A shock tube apparatus was developed for the experimental component of this study. Various factors, such as the effect of different nozzle geometries and driven channel pressures, were examined. Also, a model of the shock tube was developed for computational fluid dynamics (CFD) simulations. These simulations were generated for comparison with the experimental results and to provide additional information regarding the nature of the flow behaviour.Experimental and numerical pressure-time profiles confirm the appearance of transient radial wave activity following the initial incidence of the normal shock wave on the convergence region of the nozzle. The results establish that the strength of this activity is markedly dependent upon the nozzle convergence wall angle and the location within the shock tube

A study of the interaction of a travelling shock wave with a solid-propellant rocket motor head end

Experimental and numerical studies have been undertaken to examine various aspects pertaining to the interaction of an incident travelling shock wave with a solid rocket motor's head end (forward section), in order to identify any potential gasdynamic mechanism of wave reinforcement pertinent to combustion instability behaviour in these motors. A cold-flow experiment, based on a shock tube scheme tailored to the present application, has proved to be useful in providing information surrounding the interaction process. Both experimental and numerical results (CFD simulations) confirm the existence of substantial transient radial wave development superimposed on the base reflected axial shock wave. These results illustrate the potential weakness of one-dimensional flow models for certain engineering applications, where important multidimensional phenomena, such as those observed in this work, may not be captured. By analogy to actual propulsion system combustion chambers, the transverse wave activity is potentially a factor in supporting an augmentation of the local combustion rate in the head-end region of a rocket motor combustor.

An investigation of the interaction between a travelling shock wave and a solid rocket motor nozzle

A gasdynamic mechanism has been identified as a potential source of combustion instability in solid-propellant rocket motors (SRMs). This mechanism involves the reinforcement of a reflected shock wave in the nozzle convergence region of an SRM's exhaust nozzle. A shock tube apparatus was developed for the experimental component of this study. Various factors, such as the effect of different nozzle geometries and driven channel pressures, were examined. Also, a model of the shock tube was developed for computational fluid dynamics (CFD) simulations. These simulations were generated for comparison with the experimental results and to provide additional information regarding the nature of the flow behaviour. A gasdynamic mechanism has been identified as a potential source of combustion instability in solid-propellant rocket motors (SRMs). This mechanism involves the reinforcement of a reflected shock wave in the nozzle convergence region of an SRM's exhaust nozzle.A shock tube apparatus was developed for the experimental component of this study. Various factors, such as the effect of different nozzle geometries and driven channel pressures, were examined. Also, a model of the shock tube was developed for computational fluid dynamics (CFD) simulations. These simulations were generated for comparison with the experimental results and to provide additional information regarding the nature of the flow behaviour.Experimental and numerical pressure-time profiles confirm the appearance of transient radial wave activity following the initial incidence of the normal shock wave on the convergence region of the nozzle. The results establish that the strength of this activity is markedly dependent upon the nozzle convergence wall angle and the location within the shock tube

A study of the interaction of a travelling shock wave with a solid-propellant rocket motor head end

Experimental and numerical studies have been undertaken to examine various aspects pertaining to the interaction of an incident travelling shock wave with a solid rocket motor's head end (forward section), in order to identify any potential gasdynamic mechanism of wave reinforcement pertinent to combustion instability behaviour in these motors. A cold-flow experiment, based on a shock tube scheme tailored to the present application, has proved to be useful in providing information surrounding the interaction process. Both experimental and numerical results (CFD simulations) confirm the existence of substantial transient radial wave development superimposed on the base reflected axial shock wave. These results illustrate the potential weakness of one-dimensional flow models for certain engineering applications, where important multidimensional phenomena, such as those observed in this work, may not be captured. By analogy to actual propulsion system combustion chambers, the transverse wave activity is potentially a factor in supporting an augmentation of the local combustion rate in the head-end region of a rocket motor combustor.