• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.507-514
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• 2012

In the present research, NASA LRB plume radiation models are reconstructed with Thermal Desktop software, where the radiation to vehicle base environment can be calculated. The calculation shows the similar radiation heat compared to NASA prediction. Based on LRB plume radiation model, a KSLV-II thermal radiation model is proposed.

• 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 Radiation Protection and Research
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• v.15 no.2
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• pp.51-56
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• 1990

The dispersing model of radioactive plume in the atmosphere was assumed to form finite ellipseshaped volumes rather than a single plume and gamma absorbed doses from the plume were computed using the proposed model. The results obtained were compared with those computed by the Gaussian plume and the circular approximation models. The results computed by the proposed ellipse-shaped approximation model were close to those by the Gaussian plume model. and more accurate than those by the circular approximation model. The computing time for the proposed approximation model was one fortieth of that for the Gaussian plume model.

• Economic and Environmental Geology
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• v.52 no.5
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• pp.337-345
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• 2019

The hypothesis of ridge subduction which explains the Cretaceous igneous activities in East Asia including China, Korea and Japan, has been widely accepted in the society. Especially, the hypothesis explains the southwest-to-northeast migration of the Cretaceous adakite emergence in Southwest Japan. However, the hypothesis has several issues because the geochemical analyses and plate reconstruction model are not consistent with the consequences of the ridge subduction. To resolve the issues, a new hypothesis of the plume-continent and plume-slab interaction is suggested, which explains the igneous activities during the Cretaceous. In this review, I briefly introduce the two hypotheses and suggest an additional future study to prove the new hypothesis.

• Journal of Korean Port Research
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• v.11 no.2
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• pp.231-240
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• 1997

In the United States, a number of ocean outfalls discharge primary treated effluent into deep sea water and contribute for more efficient wastewater treatment. The long multiport diffuser connected by long pipe from a treatment plant discharge wastewater into deep water due to the steep slope of the sea bed. However, Plume discharged from the diffuser can have significant impacts on coastal communities and possibly immediate consequence on public health. Therefore, there have been growing interests about the dynamics of plume in the vicinity of the ocean outfalls. It is expected that the ocean outfall should be considered for more efficient and reliable wastewater treatments as soon as possible around coastal area in South Korea. A number of studies of plume ynamics have used various models to predict plume behavior. However, in many cases, the calculated values of plume behavior are in significantly poor agreement with realistic values. Therefore, in this study, it is recommended that improvements should be made in the application of the plume model to more simulate the actual discharge characteristics and ocean conditions. It should be noted that input parameters in plume models reflect realistic ocean conditions like waves as well as currents. In this study, as one of the new parameters, current and long wave-influenced plume rise and initial dilution have been taken into account by using simple linear wave theory under some specific assumptions for more reliable plume behavior description. Among the improved plume models approved by EPA (Environmental Protection Agency), the RSB(Roberts-Snyder-Baurngartner) and UM(Updated Merge) models were chosen for the calculation of plume behavior, and the variation calculated by both models on the basis of long period wave was compared in terms of plume rise and initial dilution.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.11
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• pp.1056-1062
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• 2008

The interaction between thrust plume and satellite base region was investigated by using direct simulate Monte-Carlo calculations. For the accurate simulation of N2 and H2 collisions and rotation-translation transition, a variable soft-sphere model and a recent rotational relaxation model of N2 and H2 were used. For the investigation of the interaction between thrust plume and base region, the number density distribution for each species, translational and rotational temperature distributions, heat flux, and pressure were examined by direct simulation of Monte-Carlo calculations. It was found that most of the surface properties are affected by H2 collisions and a strong non-equilibrium state is observed at the base region. It was demonstrated that an accurate model is needed to simulate H2 collisions and the rotation-translation transition. The results by the present calculation are more accurate than previous direct simulation Monte-Carlo calculations because more accurate rotational relaxation models were used in simulating the inelastic collisions.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.63-69
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• 2014

The oxidizer-rich preburner's combustion tests were fulfilled in the development process of staged combustion cycle rocket engines. The exhaust plume from an oxidizer-rich preburner is relatively transparent because combustion takes place in oxidizer rich state. During hot fire tests a still and infrared images were captured to visualize the plume structure, temperature distribution and so on. In addition, the exhaust plume was numerically investigated to figure out the detailed characteristics. The combustion was not considered for the numerical modeling, but the mixing of exhaust plume with circumstantial air was modeled by species transport model with several turbulence models. The inner structure of plume was configured out by the comparison of numerical results with experimental results, and the validity of applied numerical models was verified.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.3
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• pp.185-193
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• 2013

The plume infrared signature effects at various flight conditions of aircraft were investigated for the purpose of reducing infrared signature level. The nozzle of a virtual subsonic unmanned combat aerial vehicle was designed through a performance analysis. Nozzle and associated plume flowfields were first analyzed using a density-based CFD code and plume IR signature was then calculated on the basis of the narrow-band model. Finally, qualitative information for the plume infrared signature characteristics was obtained through the analysis of the IR signature effects at various flight conditions.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.4
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• pp.24-36
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• 2015

In the present study, numerical predictions of infrared spectrum of rocket plume with considering effect of particles based on approximation theories were performed by using a line-by-line radiation model with radiation databases. The high-resolution radiation databases were used to predict thermal emission spectra of gas molecules within the rocket plume regime. The particles were modeled as soot particles by using 1st term approximation of Mie theory and Rayleigh approximation. The reliability of modeled effect of soot particles using the two approximation theories was verified, and the spectral radiance of rocket plume was predicted based on the verification. The results were improved in the short wavelength range by considering the effect of soot particles.

• 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.