• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.3
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• pp.85-91
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• 2005

Radiative heating of a liquid rocket base plane due to plume emission is numerically investigated. Calculation of flow and temperature fields around rocket nozzle precedes and thereby realistic plume shape and temperature distribution inside the plume are obtained. Based on the calculated temperature field, radiative transfer equation is solved by discrete ordinate method. With the sample rocket plume, the averaged radiative heat flux reaching the base plane is calculated about 5 kw/m$^{2}$ at the flight altitude of 10.9 km. This value is small compared with radiative heat flux caused by constant-temperature (1500 K) plume emission, but it is not negligibly small. At higher. altitude (29.8km), view factor between the base plane and the exhaust plume is increased due to the increased expansion angle of the plume. Nevertheless, the radiative heating disappears since the base plane is heated to high temperature (above 1000 K due to convective heat transfer.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.4
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• pp.302-306
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• 1993

Assuming Gaussian distribution of the density difference between a turbulent jet river plume and its ambient saline water, a hydrodynamic solution for the lateral spreading of a river plume is developed. Two advantages can be expected from the assumption we made. Firstly, we need not consider mixing processes in the plume in dealing with this Problem. Secondly, by Putting pressure gradients which can be obtained from the density distribution, into the equation of motion, we can solve them easily. We compared the analytic solution with the fold data of the Nakdong river plume and found reasonably good correspondence.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.1
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• pp.114-123
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• 2002

A supersonic rocket plum flowfield of kerosene/liquid-oxygen based propulsion system has been analysed using the Reynolds-averaged Navier-Stokes equations coupled with a 9-species 14-reaction finite-chemistry model. The result were compared with chemically frozen flow solution to investigate the effect of finite-rate chemistry on the plume flowfield. The computations were performed using a commercial CFD software, FLUENT 5. The finite-rate chemistry solution exhibited higher temperature caused by the reactions within the nozzle. All the chemical reactions within the plum were dominated only in the shear layer and behind the barrel shock reflection region where the temperatures are high and the effect of finite-rate chemical reactions on the flowfield was found to be insignificant. However, the present plume computation including the finite-rate chemical reaction within the plume has revealed major reactions occurring in the plum and their reaction mechanisms.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.1
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• pp.12-20
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• 2002

An integrated analysis of kerosine/LOX based KSR-III rocket body/plume flowfield has been performed. The analysis has been executed employing three kind of gas thermo-chemical models including calorically perfect gas, multiple species chemically reacting gas, and chemically frozen gas models and their effect on rocket flowfield has been accessed to provide the most appropriate gas thermo-chemical model which meets a specific purpose of performing rocket body and plume analysis. The finite-rate chemically reacting flow solution exhibited higher temperature throughout the flowfield than other gas models due to the increased combustion gas temperature caused by the chemical reactions within the nozzle. All the reactions were dominated only in the shear layer and behind the barrel shock reflection region where the gas temperature is high and the effect of finite-rate chemical reactions on the flowfield was found to be minor. However, the present plume computation including finite-rate chemical reactions revealed major reactions occurring in the plume and their reaction mechanisms and as well.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.6 no.4
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• pp.413-420
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• 1994

Dynamics of the river plume is a very complicated non-linear problem with the free boundary changing in time and space. Mixing with the ambient water through the boundary makes the problem more complicated. In this paper we reduced 3-dimensional problem into 1-dimensional one by using the integral analysis method. Basic equations have been integrated over the lateral and vertical variations. For these integrations we adopted the well-established assumption that the flow-axis component of plume velocity and the density difference of the plume with the ambient water have Gaussian distributions in directions which are perpendicular to the flow-axis of the plume. We also used the result of our previous study on the lateral spreading velocity of the plume derived under the same assumption. And entrainment was included as a mixing process. The resultant 1-dimensional equations were solved by Runge-Kutta numerical method. Consequently, comparatively easy method of numerical analysis is presented for the 3-dimensional river plume. The method can also be used for the analysis of the thermal plume of cooling water of power plants.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.399-402
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• 2005

The present numerical study describes the flow physics on the interaction between the supersonic freestream and jet plume. The compressible flow past a simplified afterbody model with a sonic nozzle is investigated using mass-averaged Navier-Stokes equations, discretized by a fully implicit finite volume scheme, and the standard $k-{\omega}$ turbulence model. The results obtained through the present study are discussed specifically regarding the effect of the plume pressure ratio, freestream Mach number and base dimensions on the location of the plume-induced shock wave generated on the afterbody by the underexpansion of the jet plume.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.1
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• pp.35-45
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• 2005

Numerical study is carried out to investigate the effects of chemistry and thermal radiation on the rocket plume flow field at various altitudes. Navier-Stokes equations for compressible flows were solved by a fully-implicit TVD code based on the finite volume method. An infinitely fast chemistry module for hydrocarbon mixture with detailed thermo-chemical properties and a thermal radiation module for optically thick media were incorporated with the fluid dynamics code. The plume flow fields of a kerosene-fueled rocket flying at Mach number zero at sea-level, 1.16 at altitude of 5.06 km and 2.90 at 17.34 km were numerically analyzed. Results showed the plume structures at different altitude conditions with the effects of chemistry and radiation. It is understood that the excess temperature by the chemical reactions in the exhaust gas may not be ignored in the view point of propulsion performance and thermal protection of the rocket base, especially at higher altitude conditions.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.68-77
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• 2012

Flow characteristics of base region of small scaled 4 nozzle clustered engine has been analyzed with CFD approach along with the tests of numerical methods. The numerical test shows that Spalart-Allmaras turbulence model is appropriate for the present research. Plumes expanded from nozzles exits collide with each other and make high pressure stagnation region. Some of collided plumes expand again reversely into the base region with supersonic speeds. The reversed plume in the base region goes out to the outer region through the minimum vent area formed by the nearest nozzle exterior surfaces. But different from the empirical theory, the minimum vent area does not play a role of throat. Additionally the temperature of the nozzle inner surface strongly affects the temperature of the reversed plumes.

• Korean Journal of Optics and Photonics
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• v.30 no.1
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• pp.1-7
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• 2019

MANPADS (man-portable air defense system) is a counterweapon system against enemy aircraft, tracking the MWIR (mid-wavelength of infrared) signature of the plume. Under foggy conditions, however, multiple scattering phenomenon caused by the particles affects the MWIR transmittance, and the MANPADS detection performance. Therefore, in this study we analyzed the lock-on range of MANPADS with varying fog conditions and plume characteristics. To analyze the optical extinction properties and transmittance in fog, Mie scattering theory and analytic solution of the radiative-transfer equation are utilized. In addition, we used flare signature as an alternative MWIR light source. We confirmed that the lock-on range could be noticeably reduced under conditions of mist, and proportional to the flare temperature.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.6
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• pp.27-33
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• 2014

2nd stage of KSLV-I, NaRo-Ho, performs CCAM not to collide with Naro Science Satellite. At that moment, the satellite should pass through the Plume Density area which was generated by KSLV-I KM residual thrust. Therefore, it is necessary to predict Plume Density field of KM residual thrust and guarantee the safety of the trajectory of payload. In this paper, DSMC method was used to simulate Plume Density by KM residual thrust and the simulation showed that the trajectory of Naro Science Satellite was safe.