• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.19-25
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• 2011

A vehicle fuel economy is very important issue in view of fuel cost and environmental regulation. The technology development for the fuel economy improvement improved the engine, power train and many components of vehicle. So, the fuel economy is much improved, but up to now the measurement of it tests the given mode(LA-4, FTP-75, etc) within computer simulation program and engine dynamo. In this paper, to deduct the method of its improvement of real road, the test vehicle ran 213Km Youngdong real highway using 3 different algorithms in computer simulation. For this, I extracted the distance and altitude data from received GPS data and calculated the grade angle, road load and accomplished the velocity profiles according to algorithms in all 213Km distance. The vehicle runs in computer with AVL Cruise simulation program using velocity profile. I calculate the fuel economy using AVL Cruise simulation result and propose the Eco-driving method of them.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.4
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• pp.67-74
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• 1999

Problems created by supersonic jet impinging on solid objects or ground arise in a variety of situations. For example multi-stage rocket separation, deep-space docking, V/STOL aircraft, jet-engine exhaust, gas-turbine blade, terrestrial rocket launch, and so on. These impinging jet flows generally contain a complex structures. (mixed subsonic and supersonic regions, interacting shocks and expansion waves, regions of turbulent shear layer) This paper describes experimental works on the phenomena (surface pressure distribution, flow visualization) when underexpanded supersonic jets impinge on the perpendicular, inclined plate using a supersonic cold-(low system. The used supersonic nozzle is convergent-divergent type, exit Mach number 2, The maximum on the plate when it was inclined was much larger than perpendicular plate, owing to high pressure recoveries through multiple shocks. Surface pressure distribution as to underexpanded ratio showed similar patterns together.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.346-350
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• 2005

Effects of the changes of a film cooling mass flow rate and operating conditions on the heat flux characteristics of the subscale calorimeter were studied. A film cooling ring with twelve orifices is inserted between the injector head and the calorimeter. The calorimeter is composed of nineteen cooling channels. When a mass flow rate of film cooling is 10.5 % of a main fuel mass flow rate, maximum heat flux at the nozzle throat is decreased by 30% compared to that without film cooling. In the OD3(of-design point) test result, maximum heat flux at the nozzle throat is increased by 31% compared to that of the DP(design point) test when a film cooling flow rate is zero.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.353-357
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• 2005

LOx post damage occurs from the development process of the full-scale gas generator which is necessary to 30 tonf class engine development was described. The cause and analysis for damage was described. The combustion test result of 4 injector, the full-scale gas generator and redesigned injector was described. Combustion instability, purge, the low momentum of LOx spray, small recess number, the low flow of LOx, and the high spray angle is main reason the possibility of knowing. The redesign for the injector in the direction of increase of recess number, increase of LOx and fuel spray angle, decrease of gap interval between the LOx post outer wall and fuel screen and increase of LOx post wall thick became accomplished.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.11
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• pp.2115-2120
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• 2017

Presently, It is required to change convergence the role of hardware system and software technology that promoted trust of In-Vehicle for integrated complex system visibility evaluation. There is possibility for the period system can invoke unpredictable confusing blank state. The blank state systems have ecosystem characteristics that are supplied, maintained and operated through the complex interactions of technology and culture. Using universal middleware can support the life-cycle model and increase the visibility of complex systems and prepare for confusing situations. In this study, based on universal middleware, data and service dynamic standardized modules were evaluated to support stable system visibility platform. The system visibility module consists of Intelligent Pervasive Cloud module, Memorial Service module and Life Cycler connection module. In addition, the analysis results are supported by various network application service standards through platform independent system and architecture.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.149-152
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• 2008

Effects of chamber configuration on combustion characteristic velocity of full-scale combustion chamber for 30-tonf-class liquid rocket engine were studied. The configurations of combustion chamber are ablative and channel cooling chamber (${\varepsilon}$=3.2) which have detachable mixing head, and single body regenerative cooling chamber which has nozzle expansion ratio of 3.5 and 12, respectively. The combustion chambers have chamber pressure of 53${\sim}$60 bar and propellant mass flow rate of 89 kg/s, and the injectors of all combustion chamber have recess number 1.0 and double-swirl characteristics. The hot firing test results at design point show that the combustion characteristic velocity of the regenerative cooling chamber which has nozzle expansion ratio of 12 is higher than that of other combustion chambers. The reasons for the above result are the increases of combustion pressure and enthalpy of kerosene which is heated due to cooling of the chamber wall before injection into the combustion field.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.168-172
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• 2008

Hot firing tests of sub-scale combustors were carried out to study the characteristic velocity according to the variation of propellant mass flow and injector arrangement. Test results show that there exists an effective range of relative flow-rate density on the condition of similar combustion pressure and mixture ratio. Numerical analysis has also revealed that the increase of the distance between the outermost injector array and the cylindrical chamber wall with film cooling increases the region of low mixture ratio near combustion chamber wall and it decreases the characteristic velocity of the combustor. Thus, it was confirmed that these two factors play an important part in improving the performance of LRE combustor on a predetermined chamber pressure.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.627-630
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• 2009

Ejector system can induce the secondary flow or affect the secondary chamber pressure by both shear stress and pressure drop which are generated in the primary jet boundary. Ejectors are widely used in a range of applications such as a turbine-based combined-cycle propulsion system and a high altitude test facility for rocket engine, pressure recovery system, desalination plant and ejector ramjet etc. The primary interest of this study is to set up an configuration and operating conditions for an ejector in the condition of sonic and subsonic. Experimental and theoretical investigation on the sonic and subsonic ejectors with a converging-diverging diffuser was carried out. Numerical simulation was adopted for an optimal geometry design and satisfying the required performance. Also, some ejectors with a various of nozzle throat and mixing chamber diameter were manufactured precisely and tested for the comparison with the calculation results.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.451-454
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• 2006

This paper describes the results of cold flow test and hot firing tests of an uni-element coaxial swirl injector and hot firing tests of a subscale combustor, as to the development effort of coaxial swirl injector for high performance liquid rocket engine combustor. A major design parameter for coaxial swirl injector is the recess number of a bi-swirl injector. The results of hot firing tests of the uni-element injector combustor and the sub-scale combustor are analyzed to investigate the effect of the recess number influencing on the combustion performance and pressure fluctuation. The test results of a cold flow test of the unielement combustor shows that it was shown that the change in recess number has significant effect on mixing characteristics and efficiency, while the effect of recess number on atomization characteristic is not The results of a series of firing tests using unielement and subscale combustor show that the recess length significantly affects the hydraulic characteristics, the combustion efficiency, and the dynamics of the liquid oxygen/kerosene bi-swirl injector. As a point of combustion performance, combustion efficiencies are 90% for unielement combustor and 95% for subscale combustor. The difference in the characteristic velocities between the unielement combustor and the subscale combustor may be caused by the difference in thermal loss to the combustor wall and the relative lengths of the combustion chamber. For a mixed type coaxial swirl combustor, the pressure drop across the injector increases as recess number becomes larger. The low frequency pressure fluctuation observed in unielement combustor can be related to the propellant mixing characteristics of the coaxial bi-swirl injector. The effect of the recess number on the pressure fluctuation inside the combustion chamber is more significant in un i-element combustor than the subscale combustor, of which the phenomena are also observed in time domain and frequency domain.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.11
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• pp.1087-1093
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• 2008

Regenerative cooling passage to guarantee the thermal survivability in high performance rocket engine combustors could have complex configurations of the branching/merging of channels and flow turning, etc. By applying the classical hydraulic coefficients which can be found in the literature according to the flow conditions, hydraulic characteristics in regenerative cooling passages can be obtained effectively through dividing the pressure loss into friction loss and local resistance loss. Satisfactory agreement has been obtained by comparing the present results with experimental measurement of water flow test. In addition, the present results were in good agreement with CFD results when the actual coolant, kerosene was used. Therefore, the application of the present method is expected to be useful to design regeneratively cooled combustors.