Pressure Recovery in a Supersonic Ejector of a High Altitude Turbofan Engine Testing Chamber

Owino George Omollo,공창덕(Changduk Kong) 한국추진공학회 2010 한국추진공학회지 Vol.14 No.6

초음속 이젝터의 압력회복에 관한 연구

조지(Owino George Omollo),공창덕(Changduk Kong) 한국추진공학회 2010 한국추진공학회 학술대회논문집 Vol.2010 No.11

본 연구는 최소 압력 모사로 엔진 배기가스를 배출시키기 위한 최적 이젝터 크기를 결정하기 위한 것을 목적으로 한다. 실험 챔버로 유입되는 2차 냉각 공기는 유량제어 밸브들과 진공펌프가 장착된 배출구를 통해 엔진배기가스는 분리되어 배출된다. 기존 고도시험 장치와 달리, 본 연구에 제안한 형상은 기존 이젝터의 압력 회복을 개선한 좀 더 작은 포획 면적을 가진 배기 이젝트를 사용하면 가스에 스텔링 챔버로 부터 20% 냉각 공기를 부가하여 배출시키도록 크기가 정해진다. 제안된 형상은 벨마우스 이젝터와 엔진배기 출구의 면적비가 이론적으로 약 1.2를 갖는다. 제안된 형상의 혼합 공기 모사결과에 따르면 큰 에너지는 기존 시스템 비해 좀 더 개선된 압력 회복과 감소된 전력 소모를 같음을 확인하였다. This study aims at finding an optimal exhaust diffuser design of a high altitude testing chamber for a low bypass turbofan engine (F404-402) with thrust pound force of 17,700 and air mass flow rate of 66kg/s ejecting at a speed of Mach 1.66. The final proposed ejector size has better pressure recovery characteristics and targets to reduce operational cost at engine performance testing. Conventional high altitude test chamber layout was adopted and first drawn in two dimensions using Autocad software so as to determine the gas path, the ejector frontal size was then determined from gas dynamics equations considering traditional gas ejection method where both the engine exhaust and cell cooling air are exhausted via the ejector. Modification to a smaller ejector with an alternative secondary cell cooling exhaust port was then performed and modelled in 3D using Solid Works software.

고도모사 환경챔버 개념 설계

George Owino,공창덕,최경호 한국추진공학회 2009 한국추진공학회 학술대회논문집 Vol.2009 No.11

본 연구는 MIL-HDBK-310을 기준으로 한 고도별 대기상태 즉, 온도, 습도 및 압력을 모사하여 고도에 따른 피시험물의 성능을 MIL-STD-810F 및 AIAA-2466에서 정한 시험 절차에 따라 평가하는 챔버를 개발하는 것이다. 이를 위한 대기차단 구조물, 시험부 및 공기순환유로, 고도모사 배기장치, 온도제어장치, 습도제어장치 및 설비제어장치 등을 설계하는데 고려하여야 할 사항을 기술하였다 This research is based on the altitude temperature, pressure and humidity, as defined by MIL-HDBK-310 standard and modifies this conditions to conform to the new standard MIL-STD-810F and test procedure given in AIAA-2466 from this fundamental guideline optimal design and sizing of test section, inlet, exhauster duct, temperature and humidity control was performed

Equivalent Material Properties of Thin and Thick Perforated Plate by FEM simulation

Collins Owino JUMA,Ihn NAMGUNG 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12

Perforated plates are used for the steam generator tube sheet and the Reactor Vessel Closure Head in the Nuclear Power Plant. The structural integrity of these perforated structures is vital to the operation and safety of the Nuclear Power plant. ASME code addresses the analysis of perforated plates in Section III, Appendix A-8000, with triangular perforation pattern. This paper investigates the equivalent material properties by FEM methodology. Simulation of both thin and thick perforated plates and try to re-assess ASME Section III Appendix A-8000 curve. The isotropic material properties of the perforated plate were replaced with anisotropic material properties of the equivalent solid plate and subjected to same loading and boundary conditions. The difference between the deformation of the perforated and equivalent solid plate was optimized for convergence by varying the effective elastic constants. Curves of the effective elastic constants vs ligament efficiency were generated. The equivalent material property curves obtained using FEM methodology were in good agreement with the design curve provided in ASME Section. III Appendix A-8000.

HYGROSCOPIC SWELLING EFFECT ON THIN ELECTRO-DEPOSITED CONDUCTING POLYPYRROLE FILMS

Agumba Dickens Owino,Sung Yeol Kim 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.5

Use of Visual C++ program to generate Ramjet Simulation code

George Omollo Owino,Changduk Kong(공창덕) 한국항공우주학회 2008 한국항공우주학회 학술발표회 논문집 Vol.- No.-

This paper presents on research findings of how Visual C++ program can be used to generate codes capable of performing ramjet engine simulation To understand the diversity and applicability of this tool an arbitrary ramjet model will be considered for which generated output values will be compared with those from a commercial program GASTURB 9 iterated under the same input parameters. Several governing thermodynamic equations will first be discussed in order that we understand the fundamental idea behind values printed out on the GUI. C++ compiler was chosen as a tool of use due to its availability, ease of use, ability to compute functions faster and uniquely possible to make a stand alone GUI executable in DOS mode. The program is developed in such a way that given the ambient flight conditions, burner exit temperature and several geometry areas the program generates its own input values used in the succeeding stations. A close resemblance of output values that define performance and thermodynamic state of the engine was realized between GASTURB 9 and using this code made from C++ compiler.

Systems Engineering approach to Reliability Centered Maintenance of Containment Spray Pump

이용관,정재천,Ohaga, Eric Owino,Lee, Yong-Kwan,Jung, Jae Cheon 한국시스템엔지니어링학회 2013 시스템엔지니어링학술지 Vol.9 No.1

This paper introduces a systems engineering approach to reliability centered maintenance to address some of the weaknesses. Reliability centered maintenance is a systematic, disciplined process that produces an efficient equipment management strategy to reduce the probability of failure [1]. The study identifies the need for RCM, requirements analysis, design for RCM implementation. Value modeling is used to evaluate the value measures of RCM. The system boundary for the study has been selected as containment spray pump and its motor drive. Failure Mode and Criticality Effects analysis is applied to evaluate the failure modes while the logic tree diagram used to determine the optimum maintenance strategy. It is concluded that condition based maintenance tasks should be enhanced to reduce component degradation and thus improve reliability and availability of the component. It is recommended to apply time directed tasks to age related failures and failure finding tasks to hidden failures.

스마투무인 항공기용 터보엔진(PW206C)의 장착성능에 관한 연구

공창덕,George Omollo Owino 朝鮮大學校 機械技術硏究所 2006 機械技術硏究 Vol.9 No.1

The purpose of this study is to analyze both the design and off design performance simulation of the PW206C turbo shaft engine used in the development of the smart UAV (Unmanned Ariel Vehicle) by KARI(Korean Aerospace Research Institute). Its mainly aims to investigate performance behavior at the uri-installed and installed conditions. The ways employed to be able to analyze the performance extensively were mainly carried out by comparison of performance simulation results from both the commercial program 'GASTURB 9' using compressor maps generated by Genetic algorithms (GAs) or Scaling Method, and the engine manufacturer's program 'EEPP'. Off-design performance analysis was performed through matching of both mass flow and work between engine components. The set of performance simulations of the developed analytical models was performed by a commercial program package (GASTURB9) that provides great flexibility in the choice of independent variables of the overall system. The results from the simulations are used to compare turbo shaft engine (PW206C) performance data obtained by the EEPP. At uri-installed condition, it was found that the results with the compressor map generated by GAs were relatively agreed well than those with the compressor map generated by the Scaling Method. The performance calculation results using the compressor map generated by GAs were compared at uri-installed condition and installed conditions with ECS-off and ECS-Max in variation of altitude, gas generator speed and flight speed.

Mechanical behavior of conducting polymer electrode with adhesion

K. G. Kim(김경근),Owino A. Dickens,Do-Won Heo(허도원),S. Y. Kim(김성열) 한국생산제조학회 2017 한국생산제조시스템학회 학술발표대회 논문집 Vol.2017 No.4

Selection of Architect Engineering Concept for Barge Mounted SMR Using Systems Engineering Approach

Hossen, Muhammed Mufazzal,Owino, Ohaga Eric,Jung, J.C. The Korean Society of Systems Engineering 2014 시스템엔지니어링학술지 Vol.10 No.1

The trade-off studies in the concept development stage to assess the relative goodness of alternative systems concepts for AE (architect engineering) design for the Barge Mounted SMR (BMSMR) is introduced. With respect to design margin, system performance, schedule and risk, the design selection is cond ucted using the following characteristics; barge mobility, system safety under the natural disaster (seismic), power output, interfacing with the other system, and the additional supporting functions as desalination. There are three findings that should be remedied; deficiencies in the assumed characteristics of the system being modeled, deficiencies in the test model, and excessively stringent system requirements. This study is performed using systems engineering approach with trade off matrix method. In order to execute this work, concept development stage is divided into three (3) phases as NA (needs analysis), CE (concept exploration), and CD (concept definition).