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이종 추진제를 적용한 이중추력 로켓모터 계면에서의 성능 과도 현상에 관한 연구
김경무(Kyungmoo Kim),이기연(Kiyeon Lee),김정은(Jeongeun Kim) 한국추진공학회 2021 한국추진공학회지 Vol.25 No.2
In this study, we developed a method to predict/analyze the performance of a dual thrust rocket motor that has 2 kinds propellant charged in axial direction. When transitioning from the booster to the suspender stage, a transient phenomenon related to performance occurred at the interface. The causes and characteristics of the transient phenomenon were investigated by comparing them with the results of the combustion test. It was confirmed that the performance transient phenomenon is sensitively generated not only by the shape design between the propellants with different properties of the propellant, but also by errors in manufacturing due to the propellant curing shrinkage.
김경무(Kyungmoo Kim),길태옥(Taeock Khil),류태하(Taeha Ryu) 한국추진공학회 2017 한국추진공학회지 Vol.21 No.2
Nozzleless booster is one of the applicable components for integral rocket ramjet (IRR). In order to predict nozzleless solid booster performance, the simplified theoretical analysis was applied for L/D=5, 6, 7, 9, 11, and 13. Al-HTPB and Zr-HTPB propellant with a high metal content were used to increase the hardness because of the combustion gas flow effect. It was found that the trends between the simplified theoretical analysis and experiments were similar.
김경무(Kyungmoo Kim),길태옥(Taeock Khil),홍명표(Myungpyo Hong),도은성(Yeunsung Doh) 한국추진공학회 2016 한국추진공학회지 Vol.20 No.1
The propellant mixer for charging of solid rocket motors is one of the most important equipments. For the propellant mixer is export control item, it’s hard to purchase it directly from abroad. The Mixer was developed locally to overcome export control which precludes us from import. This paper includes the introduction for general mixers and the process of mixer development progressed by LIGNex1. Finally, The mixer is verified the performance using measurements of clearance between blade-blade and blade-bowl and flow simulation with ADINA.
김경무(Kyungmoo Kim),김정은(Jeongeun Kim),임재일(Jaeil Lim),박성한(Sunghan Park) 한국추진공학회 2021 한국추진공학회지 Vol.25 No.1
This paper describes the development for the dual thrust rocket motor with two types of propellants with different combustion characteristics. We developed the composition of two kinds of propellant to be applied to a rocket motor, and improved a propellant charging process in a free grain type to improve the adhesion method and the problems of adhesion between different propellants. In addition, to meet the ignition phenomenon as a small rocket motor, the ignition delay was improved by applying a nozzle plug developed in a high density foam. The propulsion rocket motor reflecting this design and the improved manufacturing process was evaluated through a ground performance test.
양희성(Heesung Yang),임지환(Jihwan Lim),김경무(Kyungmoo Kim),이지형(Jihyung Lee),윤웅섭(Woongsup Yoon) 한국추진공학회 2008 한국추진공학회 학술대회논문집 Vol.2008 No.5
A simplified model for an isolated aluminum particle burning in air is presented. Burning process consists of two stages, ignition and quasi-steady combustion (QSC). In ignition stage, aluminum which is inside of oxide film melts owing to the self heating called heterogeneous surface reaction (HSR) as well as the convective and radiative heat transfer from ambient air until the particle temperature reaches melting point of oxide film. In combustion stage, gas phase reaction occurs, and quasi-steady diffusion flame is assumed. For simplicity, 1-dimesional spherical symmetric condition and flame sheet assumption are also used. Extended conserved scalar formulations and modified Shvab-Zeldovich functions are used that account for the deposition of metal oxide on the surface of the molten aluminum. Using developed model, time variation of particle temperature, masses of molten aluminum and deposited oxide are predicted. Burning rate, flame radius and temperature are also calculated, and compared with some experimental data.
최용규(Yongkyu Choi),최재성(Jaesung Choi),김미리(Miri Kim),김경무(Kyungmoo Kim) 한국추진공학회 2015 한국추진공학회 학술대회논문집 Vol.2015 No.11
액체 추진제의 취급과 저장 위험성을 해소하고, 고체 추진제의 추력 크기 조절 한계성을 극복하기 위하여 1950년대부터 고안된 젤 추진제는 목적에 따라 다양하게 연구 개발되어 왔으며, 최근 들어 젤 추진체계의 설계제작과 지상연소실험 및 비행시험 시현이 수행되고 있다. 본 논문에서는 과거 연구개발 이력을 정리하고, 추진기관 체계 구현화를 위한 소요기술을 분석함으로서 앞으로 나갈 방향을 제시한다. For eliminating the risk of storage and handling in liquid propellant and for overcoming the limitations of throttling in Solod Rocket, Gel propellant has been studying in various areas since 1950’s. Recently some outputs of those research areas are demonstrated through design, manufacturing, static test and flight test. In this paper, It presents a direction of the gel propulsion system by reviewing the past and now research history and analyzing the required technology for the its development.
김경무,윤용화 대구대학교 기초과학연구소 1997 基礎科學硏究 Vol.14 No.1
객관적인 성적평가를 하기위하여 성적자료를 변환하는 SAS 프로그램을 개발하였고 이를 실제 자료에 적용하여 분석하여 보았다. In order to make obsective scores, SAS program that transforms the original scores is developed and is applied to real data.
김경무 대구대학교 기초과학연구소 2003 基礎科學硏究 Vol.19 No.3
The Zero-Inflated Poisson regression is a model for count data with exess zeros. The Zero-Inflated regression model are useful for accommodating the overdispersion often observed among outcomes. For exmple, it is used in an experiment concerning soldering defects on printed wiring boards. In this article we try to simulate to estimate regression parameters for the Zero-Inflated Poisson Regression Model. We study aand simulate zero inflated Poisson regression model in this paper.