Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society of Propulsion Engineers
Journal Basic Information
Journal DOI :
The Korean Society of Propulsion Engineers
Editor in Chief :
Volume & Issues
Volume 6, Issue 4 - Dec 2002
Volume 6, Issue 3 - Sep 2002
Volume 6, Issue 2 - Jun 2002
Volume 6, Issue 1 - Mar 2002
Selecting the target year
Flow Characteristics of 2 Dimensional Supersonic Nozzle in Overexpanded Conditions
Journal of the Korean Society of Propulsion Engineers, volume 6, issue 2, 2002, Pages 1~7
In the modern propulsion systems, requited thrust is obtained using a nozzle. Sometimes shock and induced boundary layer separation is generated in an over-expanded convergent-divergent supersonic nozzle. It occurs because the nozzle expansion ratio is too large for a given nozzle pressure ratio (NPR). This phenomenon can be explained that it redefines effective nozzle geometry, shorer nozzle geometry and lower pressure ratio, in a given pressure ratio. Numerical studies were conducted about a fixed geometry 2D nozzle in overexpanded condition and compared with Hunter's experimental result. For the numerical simulation of the supersonic nozzle, Navier-Stokes equations are considered and as a turbulent model,
blended SST two equation turbulent model is used. The characteristics of
-shape shock systems due to the interaction of shock and boundary layer was investigated in a low NPR. And the result of comparison of thrust value shows that a fixed geometry nozzle can cover required flight mission.
Numerical Prediction of Spray Combustion and Film Cooling in a Liquid Rocket Engine
Journal of the Korean Society of Propulsion Engineers, volume 6, issue 2, 2002, Pages 9~17
For turbulent spray combustion flows a coupled numerical procedure was developed, This method was discretized by using generalized curvilinear coordinates to handle complex geometries. The preconditioning and eigenvalue rescaling techniques were employed to provide efficient convergences over a wide range of subsonic Mach numbers. The accuracy was validated by simulating the laminar cavity flow. The film cooling effect of a liquid rocket engine (KSR-III) were investigated by a spray combustion analysis. The film cooling showed a negative effect on the combustion efficiency. In the combustion chamber wall, the film cooling effect was revealed to be promoted by the production of fuel rich zone.
A study of the smokeless liner formulation and smoke characteristics
Journal of the Korean Society of Propulsion Engineers, volume 6, issue 2, 2002, Pages 19~27
The smokeless liner, was required to propulsion system of gas generator, was developed by appling oxamide as a filler and HTPB system as a binder. Relative quantities of smoke produced during burning of liner by propellant combustion was measured by using smoke chamber. The smoke of the smokeless liner containing 50% of oxamide as filler was reduced to 1/10 as compared with conventional liner containing silica as filler. This result was showed by ground test of gas generator.
Effect of Swirl Cup Geometry on Spray Characteristics in Gas Turbine Engine
Journal of the Korean Society of Propulsion Engineers, volume 6, issue 2, 2002, Pages 29~36
Experiments have been performed to investigate the effect of secondary venturi tip angle on flow and spray characteristics in gas turbine combustor with a swirl cup assembly. Three variations of secondary venturi tip angle are made: converging, straight and diverging angles. It is found that the variation of venturi tip angle results in the significant changes of flow and spray characteristics in gas turbine combustors, such as the size and location of recirculation zones. drop size and mass distribution affecting combustion efficiency and NOx emissions. In diverge case, central toroidal recirculation zone(CTRZ) exists near the exit, which is known to be beneficial for flame stability. But in converge case, the finest SMD distribution and uniform mass distribution are found and CTRZ is longer than other cases. Consequently, high combustion efficiency and low pollutant emission are expected in converge case.
Theoretical Model of Coaxial Twin-Fluid Spray In a Liquid Rocket Combustor
Journal of the Korean Society of Propulsion Engineers, volume 6, issue 2, 2002, Pages 37~44
A theoretical study of spray and combustion characteristics due to coaxial twin-fluid injection is conducted to investigate the effects of liquid jet property, droplet size, contact length and liquid jet velocity. Model is properly validated with measurements and shows good agreement. Prediction of jet contact length, droplet size, liquid jet velocity reflects genuine features of coaxial injection in physical and practical aspects. Both the jet contact length and tile droplet size are reduced in a linear manner with an increase of injector diameter. Cross sectional area of liquid intact core is reduced with augmented jet splitting rate, thus the jet is accelerated to maintain the mass continuity and with an assistant of momentum diffusion by burnt gas.
Experimental Observation of Instability of Supersonic Submerged Jets
Journal of the Korean Society of Propulsion Engineers, volume 6, issue 2, 2002, Pages 45~52
An experimental investigation on the structure and dynamic behavior of two dimensional over-expanded air jets exiting into water was carried out. The hish speed digital video imaging and static pressure distribution measurement were made to characterize the structure and time-dependant behavior of the jets. Mach number at the jet exit was 2.0 and was slightly less than the value predicted by the ideal nozzle calculation. Variance of jet spreading angle at different stagnation condition was measured as a function of mass flow rate. Periodic nature of the air jet distortion in water was observed and the frequency of the repetition was approximately 5-6 Hz for all cases tested. Three characteristic length scales were defined to characterize jet structure.
, maximum width of the plume when the periodic instability occurs,
, width of the jet where secondary reverse flow entrained jet flow and
, distance from the jet exit to the location where entrainment of the secondary reverse flow occurs. The ratio of
decreased with increasing stagnation pressure, i.e. mass flow rate.
increased with increasing stagnation pressure. The temporal behavior of static pressure measurements also showed peak around frequency of 5, which corresponds the frequency obtained by visual measurements
Steady-state and Transient Performance Simulation and Limit Control for Compressor Surge and Turbine Over-temperature of Turboprop Engine (PT6A-62)
Journal of the Korean Society of Propulsion Engineers, volume 6, issue 2, 2002, Pages 53~63
The steady-state and transient performance simulation program for a turboprop engine(PT6A-62) was developed. Specially this program included some algorithms, such as flat-rated behaviors in performance and limit control algorithms to prevent the compressor surge and the compressor-turbine inlet limit temperature overshoot. In order to minimize analysis errors, on interpolation method in component characteristics using matching errors and specific heat and specific heat ratio, which are functions of temperatures were used. The developed steady state performance analysis program can handle various conditions such as altitude, bleed extraction, inlet temperature and pressure and part throttle, and the transient performance analysis program incorporated a general mode for transient simulation and a control mode for prevention of the compressor surge and the turbine inlet limit temperature overshoot.
Optimal Supersonic Diffuser Design of Integrated Rocket Ramjet Engine
Journal of the Korean Society of Propulsion Engineers, volume 6, issue 2, 2002, Pages 65~74
Optimal supersonic diffuser shape of integrated rocket ramjet engine was derived which maximizes the total pressure recovery. Mass flux is considered as a design constraint and the second oblique shock angle of the external ramp, the cowl-lip angle and the throat area are selected as design variables. Refined response surface method through design space transformation technique was developed and employed, and high confidence level of the regression model could be obtained. Genetic algorithm was implemented for both system optimizer and subspace regression model optimization. Virtual nozzle was located at the end of throat to adjust the back pressure. With only 20 aerodynamic analyses, optimal supersonic diffuser shape which has 14% improved total pressure recovery characteristics was successfully designed.
Numerical Study of Turbulence Modeling for Analysis of Combustion Instabilities in Rocket Motor
Journal of the Korean Society of Propulsion Engineers, volume 6, issue 2, 2002, Pages 75~84
A numerical analysis of unsteady motion in solid rocket motors with a nozzle has been conducted. The numerical formulation including modified
turbulence model treats the complete conservation equation for the gas phase and the one-dimensional equations in the radial direction for the condensed phase. A fully coupled implicit scheme based on a dual time-stepping integration algorithm has been adopted to solve the governing equations. After obtaining a steady state solution, pulse and periodic oscillations of pressure are imposed at the head-end to simulate acoustic oscillations of a travelling-wave motion in the combustion chamber. Various steady and unsteady state features in the combustion chamber of a rocket motor has been analyzed as results of numerical calculations.