• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.664-671
• /
• 2017

This paper presents a numerical analysis of behaviors of rear closer of vertical launch system under rocket plume based on fluid structure interaction analysis. The rocket plume loading is modeled by fully Eulerian method and elasto-plastic behavior of rear cover is calculated by total Lagrangian method based on a 9-node planar element. The interface motion and boundary conditions are described by a hybrid particle level-set method within the ghost fluid framework. We compare the fluid flow pattern between different rear closer models which are elast-plastic and rigid deformation.

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

• 한국전산유체공학회:학술대회논문집
• /
• 2008.03b
• /
• pp.440-443
• /
• 2008

Plume radiation has been measured during ground tests of KSLV-I kick motor in order to predict the thermal load on the equipment around the kick motor at flight. The measuring positions are the kick motor base, and the measured heats were about 2${\sim}$5 w/cm$^2$. The measured heat showed a lot of shot fluctuation in their values, and the radiative heats at the latter half of time are higher than those of the first half. A plausible explanation for these phenomena was given as the variation of alumina particles with time. The radiative heats along the plume axis were also measured recently at 8 positions with 1.5m radius from plume axis, but only the initial parts of the results could be acceptable because the sensor were damaged by the accumulated heat. The strongest heat occurred at the middle of the plume, which can be explained with different view factors. Despite of the plausible explanation, it seems to need more analysis because the plume structure such as temperature, alumina particle, after burning has not been revealed until yet. The measure heat flux has been reflected in the prediction of the plume radiation at high altitude where the kick motor operates.

• Aerospace Engineering and Technology
• /
• v.10 no.1
• /
• pp.129-135
• /
• 2011

A study of efficient plume cooling by core water injection type was performed by computational fluid dynamics. A side injection type is well known, on the contrary, a core injection type is not well known. In order to figure out the characteristics of core injection type, several calculations were performed by computational fluid dynamics along various mass flow rates and locations of water injection. On the basis of analysis it was the adequate cooling condition that water mass flow rate to total mass flow rate was two times at least and location of water injections was L/De=1.2.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2003.05a
• /
• pp.266-269
• /
• 2003

During liquid rocket engine combustion, the resulting combustion gas has flow characteristics of high temperature and high velocity. An experimental study was performed to obtain basic data for a flame deflector design that is endurable under such flow characteristics. While the injected-water cools down the combustion plume, temperature and pressure of the plume was measured. As the experiment is being performed, gas temperature was measured using infrared cameras, and the gas temperature data was compared with the temperature data from the sensor in the plume. With the results of this experiment, we were able to obtain applicable temperature data for flame deflector design and predict the performance and structural strength required for installation of water injector.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.739-740
• /
• 2010

Numerical studies were performed to investigate an effective water cooling type for reducing the thermal load of deflector in test facility with two cooling types and various mass flow rate conditions. According to analyses a core water injection type was superior to a side water injection fro the viewpoint of reducing the thermal load of deflector.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.11
• /
• pp.957-964
• /
• 2016

This paper presents numerical investigation on behaviors of the rear cover in the vertical launcher under rocket plume loading by using fluid-structure interaction analysis. The rocket plume loading is modeled by the fully Eulerian method and elasto-plastic behavior of the rear cover is predicted by the total Lagrangian method based on a 9-node planar element. The interface motion and boundary conditions are described by a hybrid particle level-set method within the ghost fluid framework. The present results will be compared with the experimental data in the future.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.1135-1139
• /
• 2017

Spatial distribution of chemical species in flame is a important indicator understanding the flame structure and combustion characteristics, and optical emission spectroscopy has been widely used for the measurement because of its simple and non-intrusive methodology. In this study, we suggest the feasibility of the measurement of chemical species (OH radical) distribution in rocket plume using optical emission spectrometer which was developed for the spatially resolved measurement along the line-of-sight. In order to predict the ground state concentration of species from the measured emission intensity by optical emission spectrometer, we consider thermal and chemical excitation mechanisms in flame, and assume thermodynamic equilibrium for the thermally excited species. We also present the spatial resolution and the correction of collection characteristics of the optical emission spectrometer depending on object distance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.03a
• /
• pp.266-271
• /
• 2008

Generation mechanisms of pressure waves from the H-IIA launch vehicle are analyzed numerically. The Mach wave radiated downstream from wavy shearlayer of supersonic exhaust plume is revealed to be the dominant noise source. Reflecting from the constructions of the launch-pad, the Mach wave turns to propagate to the vehicles. It was also found that the fluctuating supersonic plume entering into the flame duct is the dominant noise source that appears in the flame duct. Then, the pressure wave propagates through the flame duct and is ejected outside to the vehicle.

• Aerospace Engineering and Technology
• /
• v.11 no.1
• /
• pp.126-134
• /
• 2012

The Single Species, Unreacted Flow Model which is effectively applicable on the computational analysis of rocket exhaust flow is introduced in this paper. The basic concept of this model had been originated from chemically frozen analysis of hot air but it was complemented by compensating molecular weight and specific heat which was obtained CEA code analysis of exhaust plume. Comparing single species, unreacted model with the finite chemistry model, unreacted model can reduce calculation time to 1/5 while it makes similar simulation results.