• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2000.04a
• /
• pp.26-26
• /
• 2000

KM(Kick Motor)는 항우연에서 주관하여 개발하고 있는 3단형 과학관측로켓(KSR-III)이다. 본 연구는 이 KM에 적용되는 추진제 개발로서 추진기관에서 요구하는 성능, 밀도, 연소특성, 기계적특성, 점화성, 추진제/라이너/EFDM 접착력을 달성하고, 장기저장시 추진제에 작용하는 온도, 중력등 하중에 대한 추진제의 내구성을 확인하는 수면예측시험을 통해 KM이 사용하는 기간중 요구성능을 발휘할 수 있는 추진제 개발을 목표로 하고 있다. 본 논문에서는 KM 추진제 개발중 1차적으로 추진기관 요구성능을 달성하기 위해서 추진제 성능분석을 통한 기본조성을 설정하고, 이 기간조성을 토대로 밀도, 연소특성, 기계적 특성, 추진제/라이너/EPDM 접착력 실험 결과등을 정리하였고, 추진제 성능을 확인하는데 일반적으로 널리 이용하는 있는 표준모타(ST-8)에 적용하여 이론적 성능분석 및 실제 연소시험을 실시하여 그 결과를 비교 분석하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.11
• /
• pp.1081-1086
• /
• 2010

The technical procedure of an enhancement of a 120 mm rocket assisted projectile has here addressed by analyzing the ballistic performance with several the solid rocket propellants and shell designs. The performance was evaluated by aero-ballistic analyses and static ground tests of the rocket motor. Consequently, firing tests showed that one of tested models gave about 70% of extended range compared with conventional projectiles.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2018.05a
• /
• pp.172-174
• /
• 2018

기존선형과 저항을 최소화하는 최적선형에 대한 에너지효율 성능을 평가하는 것이다. 설계 흘수와 설계 선속을 고려하여 대상선박의 선수부 형상을 검토하였다. 실제 운항 상태에서 대상선박의 저항성능을 평가하였다. 상용 전산유체역학(CFD) 코드와 수조 모형시험 자료는 유효마력 평가를 위해 사용되었다. 실제 운항 상태를 고려하여 최소저항을 가지는 최적선형을 제시하였다. 기존선형과 최적선형에 대하여 3가지 선속에서 유효마력을 추정하였다. 최적선형의 저항성능은 기존선형과 비교하여 볼 때 설계속도(12노트)에서 약 6% 향상된 결과를 보여 주었다. 준추진효율 계수(ETAD, ${\eta}D$)는 모형시험 자료를 활용하였다. 에너지 효율 성능은 년간 운항일수, 벙커C유 가격, 1일 연료사용량 그리고 연료소비계수를 바탕으로 작성되었다.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.05a
• /
• pp.602-607
• /
• 1996

원자력 발전소의 효율증대 및 경제적인 측면에서 2차계통 구성부품의 보수 및 유지를 위해서는 발전소 2차계통 구성 기기의 성능저하로 인한 Heat Rate의 변화와 그에 따른 출력변화를 감시하는 것이 무엇보다 중요하다. 이를 위하여, 영광 3호기의 성능보증 시험시 사용한 방법을 이용하여 Heat Rate를 계산하는 프로그램을 개발하였으며, 이 프로그램을 이용하여 2차계통 주요 구성 기기의 성능저하에 따른 Heat Rate의 변화율 계산을 수행하였다. 이 프로그램의 계산결과와 영광 3호기 성능보증시험결과를 비교하여 이 프로그램이 Heat Rate를 정확히 계산할 수 있음과, Heat Rate의 변화율 계산의 타당성을 확인하였다. 또한, Heat Rate의 변화율을 이용한 2차계통 주요 구성 기기의 성능진단 시스템의 논리를 제시하였다.

• Journal of the Korean Wood Science and Technology
• /
• v.36 no.1
• /
• pp.36-44
• /
• 2008

It is necessary to assess wood quality and strength of the clear specimens from used members in old wooden structures for the reuse of old members on the same structure or a new structure. Wood species classification by microscope observation of each wood member that was used in truss cord and temple, and several physical and strength tests by the specification of present KS standards were conducted to compare with some references. From the comparison of strengths with references, Korean larch gives relatively better wood quality and mechanical properties than other wood species. No significant deterioration of cell wall was found by microscopic observation for the sound wood part that was selected visually. Tensile specimens with 3 mm in thickness on the middle span showed greater strength than 5 mm thick specimens, which explains that dimension of tensile specimen should be examined for evaluating precise tensile strength properties. Other tests, compression, shear, and bending, are adoptable for each strength properties. Test methods for the evaluation of basic strengths and fastener connections for old wood species should be further examined.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.5
• /
• pp.507-517
• /
• 2010

The KOREAN AIR - R&D Center has developed a solar array for STSAT-2 Flight Model, SaTReC-KAIST, using a fully localized technology and has verified the performance through a launch vibration test, orbit environment test and electrical performance test. The solar array will be launched at NARO Space Center by KSLV-I which is the first Korean launch vehicle, in May 2010. In this paper, a current-voltage curve that shows the power characteristics of solar arrays was derived by applying elements that affects the power performance of STSAT-2's solar arrays to the solar cell equivalent models. The result was compared to LAPSS test results, and accuracy of the solar cell equivalent model and the power performance simulation has been analyzed.

• Journal of the Korean Wood Science and Technology
• /
• v.43 no.4
• /
• pp.511-517
• /
• 2015

Sound absorption capability of the flame resistant treated sawdust-mandarin peel composite particleboard was were estimated by two microphone transfer function methods. The weight of flame resistant treated board slightly increased by the treatment. The treatment improved fire retardant performance by decreasing the charred area of flame resistant treated board. Sound absorption capabilities of flame resistant treated sawdust-mandarin peel composite particleboard, in the entire estimated frequency range of 500-6,400 Hz was slightly lower than those of the control specimen. Sound absorption capability of both the control and flame resistant treated sawdust-mandarin peel composite particleboards were higher than that of commercial gypsum boards, being widely used as a sound absorber for ceiling at the estimated frequency.

• Journal of Aerospace System Engineering
• /
• v.15 no.5
• /
• pp.60-71
• /
• 2021

Propeller performance measurement system for commercial propeller was designed and applied to the wind tunnel test for 3 commercial propeller models with diameters of 30 inch. The thrust and torque of the propeller was directly measured by using 6-components balance installed on the rotating axis. The measurement system was validated by using wind tunnel balance calibration equipment. Propeller test stand including measurement and rotating system was validated by using QTP propeller. In the hovering condition, we compared the performance test results and the specifications of the commercial propeller provided by the manufacturer and confirmed that there are differences in the thrust and the torque. We measured the propeller performance with various wind speeds, propeller models and angles of attack and was summarized by thrust coefficients. We confirmed that the trend of the thrust coefficients was different in the low angle of attack and high angle of attack. An aerodynamics database that can be used for future aerodynamic design of an unmanned aerial vehicle was secured.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.21 no.4
• /
• pp.545-560
• /
• 2019

During EPB TBM tunnelling, an appropriate application of additives such as foam and polymer is an essential factor to secure the stability of TBM as well as tunnelling performance. From the '90s, there have been many studies on the optimal injection of additives worldwidely contrary to the domestic situation. Therefore, in this paper, the foam, which is widely adopted for soil conditioning, was selected as an additive in order to investigate the effect of foam injection on TBM performance through a series of laboratory excavation tests. The excavation experiments were carried out on artificial sandy soil specimens with consideration of the variance of FIR (Foam Injection Ratio), FER (Foam Expansion Ratio) and $C_f$ (Surfactant Concentration), which indicate the amount and quality of the foam. During the tests, torque values were measured, and the workability of conditioned soil was evaluated by comparing the slump values of muck after each experiment. In addition, a weight loss of the replaceable aluminum cutter bits installed on the blade was measured to estimate the degree of abrasion. Finally, the foam injection ratio for the optimal TBM excavation for the typical soil specimen was determined by comparing the measured torque, slump value and abrasion. Note that the foam injection conditions satisfying the appropriate level of machine load, mechanical wear and workability are essential in the EPB TBM operational design.

• Journal of the Korea Society of Computer and Information
• /
• v.26 no.6
• /
• pp.63-71
• /
• 2021

This paper propose an development of the unmanned automatic test system for a portable detector using TRIZ Methodology. A new development scheme among of the unmanned automatic test system configurations was obtained after application of the TESE(Trends of Engineering System Evolution) one of the TRIZ methods. Using Pugh matrix drives some improving ideas. The key idea of this unmanned automatic test system scheme is to minimize whole test procedure time of each portable detector and to maximize the amount of portable detectors at once. Between the before and the after configurations of the 3D mechanical model find out improvements. This paper shows that the proposed development scheme improves the test performance efficiency compared to previous scheme.