• 제목/요약/키워드: Gas Cylinder

검색결과 744건 처리시간 0.027초

수직평판을 삽입한 개구부의 헬륨 및 공기 치환류 (Helium-Air Exchange Flow Through Openings with Vertical Partitions)

  • 강태일
    • Journal of Advanced Marine Engineering and Technology
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    • 제24권3호
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    • pp.79-87
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    • 2000
  • This paper describes experimental investigations of helium-air exchange flow through openings with vertical partitions. Such exchange flows may occur following rupture accident of stand pipe in high temperature gas cooled reactor. Exchange flow rates are investigated experimentally by using partitioned opening and opening with extended partition to assess fluids interference of the exchange flow at the stand pipe rupture accident. A tests vessel with the two types of opening on top of test cylinder is used in the experiments. An estimation method of mass increment is developed and applied to measure the exchange flow rate. A technique of flow visualization by Mach-Zehnder interferometer is provided to recognize the exchange flows. Amplitude and progress of interference fringes of the flows are observed and used as a support in comparison with the exchange flow rates. Flow passages of upward flow of the helium and downward flow of the air for both two types of the opening are separated by inserted partition within the opening, but in the case of partitioned opening, unseparated flow is formed at the opening entrance and the two flows interface. The exchange flow rate for the partitioned opening is not greater than that of the opening with extended partition because of the fluids interference at the entrance of opening. Finally, the fluids interference at the opening entrance is found to be one of important factors on the helium-air exchange flow rate.

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포뮬러 형태의 자작자동차 설계 및 제작 (Design and Manufacture of a Hand-made Vehicle Based on a Formula)

  • 이수진;정원선;김근비;김성걸
    • 한국생산제조학회지
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    • 제24권5호
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    • pp.568-575
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    • 2015
  • A hand-made vehicle with a formula (VF-1) was designed and manufactured with the aim of realizing a lightweight and high-performance vehicle. The driver's body weight and stiffness of the frame were considered. The vehicle was equipped with a one-cylinder Exiv 250 engine with intake manifold potting for realizing weight reduction, high performance, and low cost. The suspension system for the formula was designed through the analyses and tests of vehicle motion and equipment. In a steering system, anti-Ackerman geometry was introduced to increase the transverse force during cornering. A full electric paddle shift system was adopted to decrease the braking distance. For protection against the distortion and warping of the frame, tungsten inert gas (TIG) welding technology was used.

극저온 헬륨가스 가열장치 개발 및 시험 (Heating Apparatus Development and Tests for Cryogenic Gaseous Helium)

  • 정용갑;조남경
    • 한국추진공학회지
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    • 제15권1호
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    • pp.63-68
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    • 2011
  • 산화제로 액체산소를 사용하고 산화제 탱크 내부에 가압제 용기가 설치된 액체추진기관의 가압시스템에서는 가압제 용기에서 극저온으로 토출되는 가압제가 가스발생기 후단의 열교환기를 통과하여 극저온에서 고온으로 온도가 상승되어 추진제 탱크의 얼리지로 공급된다. 이러한 가압시스템을 개발하기 위해서는 열교환기를 모사할 수 있는 가열장치를 적용하여 인증시험을 수행하여야 한다. 본 연구에서는 가압시스템 개발시험에 적용할 수 있는 극저온 헬륨가스 가열장치를 개발하였고 이에 대한 가열시험을 수행하였다.

디젤기관 추진축계의 연성진동에 관한 연구 (제2보: 강제 감쇠 연성진동 해석) (Studies on Coupled Vibrations of Diesel Engine Propulsion Shafting (2nd Report : Analyzing of Forced Vibration with Damping))

  • 이돈출;김의간;전효중
    • 한국마린엔지니어링학회:학술대회논문집
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    • 한국마린엔지니어링학회 2000년도 추계학술대회 논문집(Proceeding of the KOSME 2000 Autumn Annual Meeting)
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    • pp.99-107
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    • 2000
  • With the results of calculation for natural frequencies, the forced reponses of coupled vibration of propulsion shafting were analysed by the modal analysis method. For the forced response analysis, axial exciting forces, axial damper/detuner, propeller exciting forces and damping coefficients were extensively investigated. As the conclusion of this study, some items are cleared as next. - The torsional amplitudes are not influenced by the radial excitation forces. - The axial vibrational amplitudes are influenced by the tangential exciting forces. An increase of amplitude is observed for the speed range in the neighbourhood of any torsional critical speed. - The coupling effect becomes larger if torsional and axial critical speed are closer together. - The axial exciting force of propeller is relatively strong, comparing with those of axial forces of cylinder gas pressure and oscillating inertia of reciprocating mechanism. Therefore, as a resume one can say, that- Torsional vibration calculation with the classical one dimension model is still valid. - The influence of torsional excitation at each crank upon the axial vibration is impotent, especially in the neighbourhood of a torsional critical speed. That means that the calculation of axial vibration with the classical one dimension model is insufficient in most of cases. - The torsional exciting torque of propeller can be neglected in most of cases. But, the axial exciting forces of propeller can not be neglected for calculating axial vibration of propulsion shafting.

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대체냉매(HFC134a, HC600a)용 밀폐형 왕복동 압축기의 성능해석에 관한 연구 (Performance analysis of a hermetic reciprocating compressor using the alternative refrigerants, HFC134a and HC600a)

  • 김정우
    • 대한기계학회논문집B
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    • 제22권7호
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    • pp.966-979
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    • 1998
  • Thermodynamic and dynamic analysis has been conducted to investigate performance variations induced by substitution of alternative refrigerants, HFC134a or HC600a for CFC12 in hermetic reciprocating compressors. For the thermodynamic analysis, mass and energy conservation laws are applied to the cylinder volume and Helmholtz resonator modeling method is adopted to describe gas pulsations at suction and discharge system. The modeling of the dynamics of the compressor mechanism has been performed with lumped mass method to analyse the bearing loads and friction losses at each bearing. To verify the correctness of this analysis, results of the performance simulation have been compared to those of calorimetric measurrements of compressor operating with CFC12. Analysis of the various losses, noise and reliability as well as performance has been conducted to present the design guideline for the compressor development with alternative refrigerants. It is found that compressors with alternative refrigerants, HFC 134a or HC600a give better COPs than those with CFC12 under the same operating conditions and especially, compressors with HC600a show better reliability and noise characteristics also.

예연소실식 디젤기관의 운전조건변화에 따른 열발생률 형태변동에 관한 고찰 (A study on the heat release rate pattern variation according to the change of operating conditions in pre-combution chamber type diesel engine)

  • 이진우;최재성;전효중
    • Journal of Advanced Marine Engineering and Technology
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    • 제11권3호
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    • pp.31-44
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    • 1987
  • Nowadays, the problems of energy and environmental pollution become serious day by day and the diesel engine, which has been proved to be superior to gasoline engine with respect to fuel consumption and ecological problems of exhaust gas, has been adopted widely for various purposes from the marine diesel engine and the dynamo engine to all kinds of engine on land. Therefore, extensive parametric studies on combustion of diesel engine should be done for its desing and improvement. To predict the behavior of diesel engien according to variable operating conditions by means of cycle simulation, the reasonable pattern of heat release rate has to be asumed. But it is necessary to know the actual variation of heat release rate in order to assume the reasonable pattern of heat release rate according to the actual operating conditions. In this paper, on a high speed small bore diesel engine with pre-combustion chamber, experimental investigations were carried out to determine the relationship between the heat release pattern and parameters such as engine load and speed. And also, the theoretical investigations about the performance variations of the above diesel engine according to the predicted pattern of heat release rate variation were performed. From the above observations, it may be said that the Fanboro indicator, which was used to get the cylinder pressure, can be used to estimate a reasonable pattern of heat release rate and it is confirmed that the pattern of heat release rate for the pre-combustion type engine is different from that of the direct injection type engine.

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동하중(動荷重)을 받는 선박용(船舶用) 디젤 엔진의 저널 베어링 유막해석(油膜解析)에 관한 연구(硏究) (The Oil Film Analysis of Dynamically Loaded proceeding Bearing in Diesel Engine)

  • 차지협;이상수;김정렬;김주태;김종석
    • 한국마린엔지니어링학회:학술대회논문집
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    • 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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    • pp.160-165
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    • 2005
  • The proceeding bearings of marine diesel engine are affected by dynamic loads from the cylinder gas pressure and the inertia force from the crank mechanism. Oil film must support the load of the shaft and it also must protect the proceeding and the bearings from damage. This study uses Goenka's new curve fit to carry out the theoretical analysis of oil film in proceeding bearings for MAN B&W 12K90MC-C and Hyundai Heavy Industry Co., Ltd HiMSEN H21/32 Engine. The applied engine's analysis results show the behavior of the proceedings in main and crank pin bearings. The results of this study will be the proper criteria for the proceeding bearings design and be available for development of the new technology in the proceeding bearing and for the high strength lining coating.

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흡기포트 선회비 변경에 따른 유동특성 및 엔진성능에 관한 연구 (A Study on the Flow Characteristics and Engine Performance with Swirl Ratio Variance of Intake Port)

  • 윤준규;차경옥
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집B
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    • pp.899-905
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    • 2000
  • The characteristics of air flow and engine performance with swirl ratio variance of intake port In a turbocharged DI diesel engine was studied in this paper. The intake port flow is important factor which have influence on the engine performance and exhaust emission because the properties in the injected fuel depend on the combustion characteristics. The swirl ratio for ports was modified by hand-working and measured by impulse swirl meter. For the effects on performance and emission, the brake torque and brake specific fuel consumption were measured by engine dynamometer and NOx, smoke were measured by gas analyzer and smoke meter. As a result of steady flow test, when the valve eccentricity ratio are closed to cylinder wall, the flow coefficient and swirl intensity are increased. And as the swirl ratio is increased, the mean flow coefficient is decreasing, whereas the gulf factor is increasing. Also, through engine test its can be expected to meet performance and emission by optimizing the main parameters; the swirl ratio of intake port, injection timing and compression ratio.

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가변형 임계 노즐유동에 관한 기초적 연구 (A Fundamental Study of a Variable Critical Nozzle Flow)

  • 김재형;김희동;박경암
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 추계학술대회
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    • pp.484-489
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    • 2003
  • The mass flow rate of gas flow through critical nozzle depends on the nozzle supply conditions and the cross-sectional area at the nozzle throat. In order that the critical nozzle can be operated at a wide range of supply conditions, the nozzle throat diameter should be controlled to change the flow passage area. This can be achieved by means of a variable critical nozzle. In the present study, both experimental and computational works are performed to develop variable critical nozzle. A cone-cylinder with a diameter of d is inserted into conventional critical nozzle. It can move both upstream and downstream, thereby changing the cross-sectional area of the nozzle throat. Computational work using the axisymmetric, compressible Navier-Stokes equations is carried out to simulate the variable critical nozzle flow. An experiment is performed to measure the mass flow rate through variable critical nozzle. The present computational results are in close agreement with measured ones. The boundary layer displacement and momentum thickness are given as a function of Reynolds number. An empirical equation is obtained to predict the discharge coefficient of variable critical nozzle.

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반용융 단조품의 제조 (Manufacturing of Product by Semi-Solid Forging)

  • 박형진;강충길;김병민;최재찬
    • 한국정밀공학회지
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    • 제16권6호
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    • pp.45-51
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    • 1999
  • The semi-solid forging is a new forging technology in which the billet is heated to the semi-solid state coexisting liquid and solid phase for making globular microstructure and subsequently formed. As the semi-solid forging is compared with conventional casting such as die casting and squeeze casting for the characteristics of its process, the product without inner defects such as gas porosity and segregation can be obtained and its microstructure is globular grain. Simutaneously, its mechanical properties are improved by globular microstructure and the lower temperature of the slug causes the cycle time of manufacturing to be shortened and the die life to be lengthened. As it is compared with conventional cold and hot forging, it is possible to minimize the equipment of production owing to a lower forming load and reduce the number of process by a followed treatment for complex shaped product. Therefore it is needed to confirm the quality of a semi-solid forged product by defining its characteristics quantitatively under these advantages. This paper investigates the formability of a master cylinder by its forming variables. And the microstructural characteristics and mechanical property of it is also studied.

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