• Journal of the Korean Society of Propulsion Engineers
• /
• v.14 no.3
• /
• pp.9-15
• /
• 2010

Numerical investigation was carried out on axisymmetric over-expanded rocket nozzle to predict flow fields of transitional shock separation patterns. The unsteady, compressible N-S equations with k-$\omega$ SST for turbulence model closure were solved using a fully implicit finite volume scheme. Computed results were in good agreement with previous experimental works. It was found that strong side-loads were generated during the transition of RSS to FSS due to the development of a vortex ring in the inviscid jet core region. Hysteresis phenomenon exhibited by the shock-separation patterns was also found during the start-up and shut-down processes.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.12 no.3
• /
• pp.9-15
• /
• 2008

Nozzle flow analyses of $30\;ton_f$-class KARI liquid rocket engine for high altitude propulsion are carried out using a chemically frozen and equilibrium flow analysis code developed previously. It is considered that the combined frozen- and shifting- equilibrium analysis is cost-effective regarding the convergence characteristics and modeling uncertainties, though the non-equilibrium analysis is most reliable approach. A dependable performance prediction could be attainable through the present analyses that account for the recombination process and thermal and kinetic energy recovery during the expansion process with viscous effects.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.11a
• /
• pp.89-93
• /
• 2008

The effect of pintle shapes and position to the thrust performance of Solid Rocket Motor was studied by experimental-aided Computational Fluid Dynamic(CFD). Among the turbulent models for RANS in Fluent, Spalart-Allmaras model was better agreement with the nozzle wall pressure distribution attained by cold-flow test than other models. When nozzle throat area was decreased, magnitude of thrust was increased. The bigger pintle size was, the more thrust of pintle tip pressure was obtained. Meanwhile the more thrust of nozzle and chamber pressure decreased. Hence, total thrust of big pintle was less than a small pintle under same throat area condition.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.15 no.3
• /
• pp.31-39
• /
• 2011

The flowfield in a solid rocket motor was simulated at the wall-injection test model, which has a fin-slot grain and submerged nozzle, and visualized by a smoke-wire. The high speed CCD camera captured the visualized images around the nozzle inlet through the grain center port. The vortical tube structure and circumferential flow patterns at the nozzle throat were visualized. The radial momentum transfer caused by the shear-interactions of slot-outlet flow, fin-base flow and grain port flow from upstream worked as the source of these phenomena.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2006.05a
• /
• pp.331-336
• /
• 2006

This paper studies the effects of the nozzle-rotor axial clearance of a supersonic turbine on turbine performance. The nozzle-rotor axial clearance of the supersonic turbine developed to drive a turbopump for 30 ton class liquid rocket engines was varied and a numerical analysis of the turbines having the different nozzle-rotor axial clearances was conducted. It has been found that turbine performance degrades with an increasing axial clearance due to the increased stagnation pressure loss in the axial clearance region.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.758-759
• /
• 2010

In this study, it was experimentally confirmed that the phenomenon of resonance effect of wave drag in two wavy walls. The channel had saw-tooth type of relief surfaces when supersonic gas flows into this channel. Experiment was carried out on the differential apparatus by conducting the comparative test of two nozzles (round sonic nozzle and two-dimensional nozzle with wavy walls). The two-dimensional nozzle was joined alternately with flat walls which had saw-tooth type of symmetrical and asymmetric reliefs. Two-dimensional nozzle was designed for the M=3 and profiled parabolic contour.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2006.05a
• /
• pp.393-397
• /
• 2006

In this study, combustion characteristics of solid propellants using sorbitol and potassium nitrate were found out. Burning rate was calculated with several combustion experiments, also specific impulse and characteristic exhaust velocity were compared with theoretical value. Thrust measured with thrust measurement system using plate spring. Mixture ratio of propellants was varied in experiments, also combustion characteristics of solid propellants which consulted experimental results was used micro solid rocket design having 1mm nozzle throat.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2007.11a
• /
• pp.248-251
• /
• 2007

The blowdown oxidizer feeding system is effective in the respect of higher reliability by the small number of parts and the absence of additional pressurization tanks, but it also has the unfavorable disadvantage such as thrust variation during the operation. Thus, in order to understand the these performance characteristics inherent in the Hybrid Rocket Motor (HRM) with blowdown oxidizer feeding system, this study proposed the integrated mathematical model to describe physical phenomena in the following parts: the oxidizer tank, combustion chamber, fuel grain, nozzle and injector.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.5 no.4
• /
• pp.40-49
• /
• 2001

The basic research on AKM(Apogee Kick Motor) for space launch vehicle was carried out. AKM which will be used as 3rd stage solid rocket motor in 3-stage Korean Sounding Rocket(III) has been developing. KM is a solid rocket motor using composite propellant based on HTPB and is composed of composite motor case and submerged nozzle. To develop KM rocket motor satisfing a given set of requirement, firstly the full-scale KM with diameter 520mm was designed, then sub-scale motors reduced about 60% were manufactured and tested. Full-scale ground firing test is accomplished two times.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2012.05a
• /
• pp.238-238
• /
• 2012

Report is devoted to place and role of numerical simulation in design of rocket propulsion systems. In introduction advanced solutions in liquid propellant rocket engines design are presented. Further essence of design process described briefly. The central place of method of solution of direct problem in design process was shown. Numerical simulation for solving direct problem of fluid dynamic was used as the alternative to theoretical and experimental approaches. Main features of numerical models of processes in propulsion systems were observed. Some results of simulation and (or) design of different types of chemical propulsion system were presented also. The combined rocket engine, rocket engine with injection of after-turbine gas into supersonic part of the nozzle, solid propellant engine and hybrid propulsion engine are under consideration.