• Title/Summary/Keyword: Ram Air

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Experimental Study on the Effect of Air Chamber Size and Operation Parameters on the Performance of a Hydraulic Ram Pump (압력실의 크기와 운전 조건에 따른 수격펌프의 성능에 대한 실험적 고찰)

  • Ngolle, Enongene Ebong George;Hong, Seong Gu
    • Journal of The Korean Society of Agricultural Engineers
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    • v.61 no.4
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    • pp.55-61
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    • 2019
  • Motor pumps cannot be used in those areas where electricity is not accessible such as remote rural areas in many African countries. Hydraulic ram pump is one of the solutions for supplying water for irrigation or domestic uses. The hydraulic ram pumps are working based on the water hammer effect for pumping without external power or electricity. This study was conducted to investigate the effect of air chamber volume and operation parameters on the performance of the hydraulic ram pump which was assembled with common plumbing parts. The experimental results showed the volume of the air chamber did not affect the performance such as discharge rate and head. When drive heights were 1.7 and 2.35 m, the maximum discharge heads were up to 7 m and 10 m, respectively. When the air chamber volume was 1 L, discharge rates were 0.23 and 2.12 L/min under the drive heights of 1.7 and 2.35 m, respectively. The average energy efficiency of the hydraulic ram pump assembled in this study was about 60% for all the experimental conditions.

A Study on Fundamental Characteristics of Underwater Ram-Jet Propulsion by PIV (PIV에 의한 수중램제트추진의 기본특성에 관한 연구)

  • 양창조;김춘식;최민선;김진구;이영호
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.3
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    • pp.36-42
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    • 2000
  • A fundamental experimental study for an alternative proposal to super-speed craft propulsion system called underwater ram-jet propulsion by high pressure air ejection as driving force was investigated. For basic study of the effects of ram-jet propulsion performance, a simple underwater ram-jet flow field was established and PIV(Particle Image Velocimetry) method was adopted to analyse the jet-induced flow appearing at ram intake, mixing chamber and nozzle. Some flow dynamics relating to the high-speed ram-jet effect were discussed for the basic understanding of the its propulsion principle.

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Comparison of RAM Target Value and Operation Data in Air Weapon Systems (야전운용자료를 활용한 항공무기체계의 RAM 목표값 비교분석)

  • Kim, In Seok;Jung, Won
    • Journal of Applied Reliability
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    • v.15 no.4
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    • pp.282-288
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    • 2015
  • Purpose : The purpose of this study is to compare the RAM (reliability, availability and maintainability) value in the acquisition phase with operational period for air weapon systems. The objective is to determine if the value of RAM is sufficient in the field, and look for any difference from the target value to some extent. Methods : For a case study, the ${\bigcirc}{\bigcirc}$ training aircraft is selected. Data from the two acquisition sources are utilized. One is the operational data in domestic aircraft through research and development, and the other is the data from imported aircraft. The two different sources were collected independently and distinctly. Results : According to the analysis, the domestic aircraft shows high deviation in RAM value compare to the imported systems. This is due to the effort of continuous reliability improvement. In the aspect of maintainability, the result shows a slight deviation, and the availability meets the requirement. Conclusion : The results of this study can be used in finding a way that can be effectively applied to the sustainability in the weapon system. If the RAM performance is significantly lower than the target value, then it is necessary to improve the design activities so that they can achieve the RAM target value.

A Study on the Autonomous Powered Ram Air Parafoil System Considering Wind Effect (바람 효과를 고려한 동력 램에어 파라포일 자동비행 시스템 연구)

  • Kim, Tae-Wook;Song, Yongkyu;Jeong, Dongho;Gwon, Oseong
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.24 no.1
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    • pp.55-61
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    • 2016
  • In this work a guidance and control system for an a powered ram air parafoil under wind disturbance is considered. After analyzing a 6 Dof and 9 Dof nonlinear dynamic models of the parafoil, wind effect is added to them. In order to actively respond to the wind acting on the transverse direction of the vehicle a new guidance algorithm is proposed. After a Hardware-In-the-Loop Simulation (HILS) study, flight tests are performed to demonstrate its potential under wind disturbances.

Study on Numerical Analysis for Ram-Air flow of Cooling Duct on the Propulsion System (추진시스템 냉각유로의 주행풍 유동에 대한 수치해석적 연구)

  • Ryoo, Seong-Ryoul;Jo, Jung-Rae;Jo, Tae-Sik;Kim, Chul-Ju
    • Proceedings of the KSR Conference
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    • 2009.05b
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    • pp.507-513
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    • 2009
  • The cooling technology of power conversion semiconductors in the propulsion system for the HEMU(High Electrical Multi Unit) are applied in water cooling method and phase change method such as the immersed type and the heat pipe type. Both of cooling systems need a condenser and a fan through forced wind to emit that is radiated heat from electric power conversion semiconductor(IGBT) stack effectively, now in the case of Japanese Fastec 360S, is using ram-air that is flowed in establishing cooling passage to propulsion system for cooling of condenser. In this research, it is that achieved the computing numerical analysis using ADINA of commertial program to examine flow characteristics and pressure distribution of ram-air for a condenser in cooling passage.

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Fundamental Experiment of Underwater Ram-jet by PIV Measurement (PIV에 의한 수중램제트의 기초실험)

  • 김춘식
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2000.05a
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    • pp.165-170
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    • 2000
  • A fundamental experimental study for a substitute proposal to super-speed craft propulsion system called underwater ram-jet propulsion by high pressure air ejection as driving force was investigated. for basic study of effect of ram-jet propulsion performances ismple underwater ram-jet flow field was established and PIV(Particle Image Velocimetry) method was adopted to analyse the jet-induced flow appearing at ram intake mixing chamber and nozzle. Some flow dynamics relating to the high-speed ejector effect were discussed for the basic understanding for the ram-jet propulsion principle.

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Spray and Combustion Characteristics of a Dump-type Ramjet Combustor

  • Lee, Choong-Won;Moon, Su-Yeon;Sohn, Chang-Hyun;Youn, Hyun-Jin
    • Journal of Mechanical Science and Technology
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    • v.17 no.12
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    • pp.2019-2026
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    • 2003
  • Spray and combustion characteristics of a dump-type ram-combustor equipped with a V-gutter flame holder were experimentally investigated. Spray penetrations with a change in airstream velocity, air stream temperature, and dynamic pressure ratio were measured to clarify the spray characteristics of a liquid jet injected into the subsonic vitiated airstream, which maintains a highly uniform velocity and temperature. An empirical equation was modified from Inamura's equation to compensate for experimental conditions. In the case of insufficient penetration, the flame in the ram-combustor was unstable, and vice versus in the case of sufficient penetration. When the flame holder was not equipped, the temperature at the center of the ram-combustor had a tendency to decrease due to the low penetration and insufficient mixing. Therefore, the temperature distribution was slanted to the low wall of the ram-combustor. These trends gradually disappeared as the length of the combustor became longer and the flame holder was equipped. Combustion efficiency increased when the length of the combustor was long and the flame holder was equipped. Especially, the effect of the flame holder was more dominant than that of the combustor length in light of combustion efficiency.

A Proposal on Analyzing Operational Mission Summary/Mission Profile and RAM Goal Setting from Operational Concepts on the Next-MILSATCOM (차기 군 위성통신체계 OMS/MP 분석 및 운용개념으로부터의 RAM 목표값 산출 제안)

  • Park, Heung-Soon;Kwon, Tae-Wook;Lee, Chul-Hwa;Park, Dae-Hyun
    • Journal of the Korea Institute of Military Science and Technology
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    • v.16 no.3
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    • pp.295-303
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    • 2013
  • The Operational Mode Summary/Mission Profile(OMS/MP) is a document which describes how a system or training device will be used in wartime and/or peacetime at the time it is field with focus on the future. OMS/MP is also typically used for the RAM goal setting in an early phase of weapon system development. This paper provides OMS/MP and RAM goal of the Next-MILSATCOM which is following military satellite system after ANASIS. We propose operational concepts, user-side OMS/MP model and RAM goal.

Performance Test and Evaluation of ACM for Fighter's External POD (전투기 외장 포드용 ACM의 성능 시험평가)

  • Paek, Seung-Yun;Seo, Ja-Won;Song, Deok-Hee;Kim, Kyeong-Su;Hong, Jae-Pyo;Park, Sung-Soon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.11a
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    • pp.527-530
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    • 2010
  • A performance test of an air cycle machine with an air to air heat exchanger was performed. The air cycle machine designed for avionics cooling in a fighter's external pod is a small turbo machine operated on the reverse Brayton air cycle driven by captured ram air which is the source of driving energy and it can be used as cooling fluid going through electronics in the pod during the flight. The air to air heat exchanger was also used to avoid moisture for avionics. The performance test have verified that the developed ACM and heat exchanger meet the design requirements.

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Thermodynamic Characteristics of an Aircraft Environmental Control System (항공기 환경제어 계통의 열역학적 특성)

  • 차재병;강병찬;오태식
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.4
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    • pp.1116-1124
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    • 1995
  • Using a cycle simulation program developed by authors, some thermodynamic characteristics of an aircraft ECS under various operating conditions are studied. When the inlet temperature of cockpit and avionics bay, as well as ram air flow, is held fixed, the effect of the change of regulated bleed pressure is examined. When the regulated bleed pressure, and the cockpit and avionics bay inlet temperature are fixed, the effect of the change of ram air flow is also investigated.