• Title/Summary/Keyword: Gas regulator

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Performance Dispersion Analysis of Gas Generator Cycle Liquid Rocket Engine (가스발생기 사이클 액체 로켓 엔진의 성능 분산 해석)

  • Choi Hwan Seok;Nam Chang Ho
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2004.10a
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    • pp.87-91
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    • 2004
  • It is definitely required to control dispersion of the rocket engine performance in order to accomplish the mission of launch vehicle successfully. We performed the dispersion analysis of gas generator cycle LRE (liquid rocket engine) accompanied with ANASYN. As a result, the vacuum thrust dispersion of the engine was $+5.34\%,\;-5.27\%$ and the mixture ratio deviated $+9.07\%,\;-9.82\%$ from the nominal value due to the errors of components and engine inlet condition of propellants. By applying the gas generator regulator only, the dispersion of the engine performance increases. Error in turbine efficiency is the most influential factor to the dispersion of engine performance.

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Design of Optimized Fuzzy Controller by Means of HFC-based Genetic Algorithms for Rotary Inverted Pendulum System (회전형 역 진자 시스템에 대한 계층적 공정 경쟁 기반 유전자 알고리즘을 이용한 최적 Fuzzy 제어기 설계)

  • Jung, Seung-Hyun;Choi, Jeoung-Nae;Oh, Sung-Kwun
    • Journal of the Korean Institute of Intelligent Systems
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    • v.18 no.2
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    • pp.236-242
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    • 2008
  • In this paper, we propose an optimized fuzzy controller based on Hierarchical Fair Competition-based Genetic Algorithms (HFCGA) for rotary inverted pendulum system. We adopt fuzzy controller to control the rotary inverted pendulum and the fuzzy rules of the fuzzy controller are designed based on the design methodology of Linear Quadratic Regulator (LQR) controller. Simple Genetic Algorithms (SGAs) is well known as optimization algorithms supporting search of a global character. There is a long list of successful usages of GAs reported in different application domains. It should be stressed, however, that GAs could still get trapped in a sub-optimal regions of the search space due to premature convergence. Accordingly the parallel genetic algorithm was developed to eliminate an effect of premature convergence. In particular, as one of diverse types of the PGA, HFCGA has emerged as an effective optimization mechanism for dealing with very large search space. We use HFCGA to optimize the parameter of the fuzzy controller. A comparative analysis between the simulation and the practical experiment demonstrates that the proposed HFCGA based fuzzy controller leads to superb performance in comparison with the conventional LQR controller as well as SGAs based fuzzy controller.

Aging Characteristics of Low Pressure LPG Regulators for Domestic Use (가정용 LPG 저압조정기의 경년특성에 관한 연구)

  • Kim Young-Gyu;Kwon Jeong-Rock
    • Journal of the Korean Institute of Gas
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    • v.3 no.1
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    • pp.58-63
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    • 1999
  • Experimental works were carried out to evaluate how the lapse of time affects the performance characteristics and the service life of low pressure LPG regulators for domestic use. Experimental results showed that the operating pressure of safety devices deviated from the opening pressure value and the closing pressure value from just 1 year after service, and the operating pressure of regulators used for 7${\~}$8 years notably deviated from the reference value of the adjusting pressure and the closing pressure. And the material properties of springs and diaphragms deteriorated after 5${\~}$6 years of service. Thus, it is estimated that low pressure LPG regulators have approximately 6 years of service life. However, it is highly recommended that regulators exceeding 5 years of service should be replaced for the safety of consumer and accident prevention even if they are operating normally.

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A Study on the Natural Evaporation Capacity of LPG Container (액화석유가스 용기의 자연 증발량에 관한 연구)

  • Jo Young-Do;Kim Ji-Yoon
    • Journal of the Korean Institute of Gas
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    • v.5 no.2 s.14
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    • pp.22-29
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    • 2001
  • The number of gas containers and the period of exchanging gas containers are vsy important in designing liquefied petroleum gas(LPG) supply system for small capacity domain. And also the evaluation of remaining LPG in containers to be exchanged is very useful information in commerce. However seldon has been studied on calculating method about those with respect to gas consumption pattern. In this study, a simulation method was developed to estimate the evaporation capacity of LPG container, the mass gas flow rate from LPG container, the temperature and vapor pressure of LPG, and the remained LPG at containers to be exchange by using LPG property equations, mass balance equation, and heat balance equation. The simulation results were correlated well with experimental data. The overall heat transfer coefficient from air to LPG is approximately $9{\~}13 kcal/m^2{\cdot}hr{\cdot}^{\circ}C$ and does not strongly affect on the evaporation capacity of LPG container. The mass gas flow rate from LPG container is constant when the vapor pressure of LPG is within pressure regulator's control range. While, out of range, it suddenly reduce to a evaporation rate which is balanced with heat transfer from air. The evaporation capacity of LPG container increased with surrounding temperature and the composition of propane, and decreased drastically with continuous gas consumption. The number of gas containers divided the number of houses using gas supply system was reduced by using automatic gas feeding device.

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A Study on Synthetic Method and Material Analysis of Calcium Ammine Chloride as Ammonia Transport Materials for Solid SCR (Solid SCR용 암모니아 저장물질인 Calcium Ammine Chloride의 합성방법 및 물질분석 연구)

  • Shin, Jong Kook;Yoon, Cheon Seog;Kim, Hongsuk
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.2
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    • pp.199-207
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    • 2015
  • Solid materials of ammonia sources with SCR have been considered for the application of lean NOx reduction in automobile industry, to overcome complex problems of liquid urea based SCR. These solid materials produce ammonia gas directly with proper heating and can be packaged by compact size, because of high volumetric ammonia density. Among ammonium salts and metal ammine chlorides, calcium ammine chloride was focused on this paper due to low decomposition temperature. In order to make calcium ammine chloride in lab-scale, simple reactor and glove box was designed and built with ammonium gas tank, regulator, and sensors. Basic test conditions of charging ammonia gas to anhydrous calcium chloride are chosen from equilibrium vapor pressure by Van't Hoff plot based on thermodynamic properties of materials. Synthetic method of calcium ammine chloride were studied for different durations, temperatures, and pressures with proper ammonia gas charged, as a respect of ammonia gas adsorption rate(%) from simple weight calculations which were confirmed by IC. Also, lab-made calcium ammine chloride were analyzed by TGA and DSC to clarify decomposition step in the equations of chemical reaction. To understand material characteristics for lab-made calcium ammine chloride, DA, XRD and FT-IR analysis were performed with published data of literature. From analytical results, water content in lab-made calcium ammine chloride can be discovered and new test procedures of water removal were proposed.

Separation Permeation Characteristics of N2-O2 Gas in Air at Cell Membrane Model of Skin which Irradiated by High Energy Electron (고에너지 전자선을 조사한 피부의 세포막모델에서 공기 중의 O2-N2 혼합기체의 분리투과 특성)

  • Ko, In-Ho;Yeo, Jin-Dong
    • Journal of the Korean Society of Radiology
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    • v.13 no.2
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    • pp.261-270
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    • 2019
  • The separation permeation characteristics of $N_2-O_2$ gas in air at cell membrane model of skin which irradiated by high energy electron(linac 6 MeV) were investigated. The cell membrane model of skin used in this experiment was a sulfonated polydimethyl siloxane(PDMS) non-porous membrane. The pressure range of $N_2$ and $O_2$ gas were appeared from $1kg_f/cm^2$ to $6kg_f/cm^2$. In this experiment(temperature $36.5^{\circ}C$), the permeation change of $N_2$ and $O_2$ gas in non-porous membrane by non-irradiation were found to be $1.19{\times}10^{-4}-2.43{\times}10^{-4}$, $1.72{\times}10^{-4}-2.6{\times}10^{-4}cm^3(STP)/cm^2{\cdot}sec{\cdot}cmHg$, respectively. That of $N_2$ and $O_2$ gas in non-porous membrane by irradiation were found to be $0.19{\times}10^{-4}-0.56{\times}10^{-4}$, $0.41{\times}10^{-4}-0.76{\times}10^{-4}cm^3(STP)/cm^2{\cdot}sec{\cdot}cmHg$, respectively. The irradiated membrane was significantly decreased about 4-10 times than membrane which was not irradiated. And ideal separation factor of $N_2$ and $O_2$ gas by non-irradiation was found to be from 1.32 to 0.42 and that of $N_2$ and $O_2$ gas by irradiation was found to be from 0.237 to 0.125. The irradiated membrane was significantly decreased about 4-5 times than membrane which was not irradiated. When the operation change(cut) and pressure ratio(Pr) by non-irradiation were about 0, One was increased to the oxygen enrichment and the other was decreased to the oxygen enrichment. The irradiated membrane was significantly decreased about 4-19 times than membrane which was not irradiated. As the pressure of $N_2$ and $O_2$ gas was increased, the selectivity was decreased. As separation permeation characteristics of $N_2-O_2$ gas in cell membrane model of skin were abnormal, cell damages were appeared at cell.

Dynamic Characteristic Analysis of KSR-III Propulsion Feeding System (KSR-III 추진기관 공급계 동특성 해석)

  • Jung, Young-Suk;Cho, In-Hyun;Jung, Tae-Kyu;Kwon, Oh-Sung
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.1008-1013
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    • 2001
  • KSR-III propulsion system designed in KARI has a gas-pressurization system for propellant feeding system. This system uses a regulator for the control of the ullage pressure of propellant tank and a venturi for passive control of propellant flowrate. This system seems to be very reliable, but the flowrate of propellant varies according to the change of acceleration with the rocket flight. In this paper, dynamic characteristic of KSR-III propulsion feeding system was analyzed in flight condition. The purpose of this research is to find the variation of off ratio and propellant flowrate change for certification condition of engine reliability test.

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A study on the system of the power expansion planning (전력수급계획 수립 체계에 관한 고찰)

  • Han, Seok-Man;Kim, Jong-Hyuk;Chung, Koo-Hyung;Kan, Dong-Joo;Kim, Balho-H.
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.564-565
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    • 2008
  • All over the world, energy environment dramatically changes because of highly oil price, global warming and reduction of greenhouse gas. The power sector is effected directly indirectly by these factors. Especially, the power expansion planning of power sector should adapt itself to new surroundings. This paper presents the new system of the power expansion planning that reflects Genco's needs, power market and variable conditions. This presented system would provide regulator and Gencos with useful information about a power planning.

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A Study on Gas Pressure Fluctuation Characteristics inside Pipe Line Passing Through a Snubber at Hydrogen Compressor (수소압축기 스너버 관로 내부의 맥동파 특성에 관한 연구)

  • Shim, K.J.;Yi, C.S.;Akbar, Wanda Ali;Chung, H.S.;Jeong, H.M.
    • Journal of Power System Engineering
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    • v.10 no.4
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    • pp.165-171
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    • 2006
  • An experiment to observe reduction of pressure fluctuation in the compressing system utilizing snubber has done. The experiment measured pressure at inlet and outlet of snubber. It used an air compressor as a model of hydrogen one. Snubber with buffer and snubber without buffer were used to get comprehensive comparison between both of that snubber. An analysis by using Fast Fourier Transform (FFT) method was conducted to verify working pressure frequency. With this method pure signal of static pressure was filtered from noisy signal. The experiment was run for several speeds of piston movement. It was controlled by adjustable frequency regulator that controled rotation of actuator motor. This was connected to the piston-reciprocating compressor with V-belt. From result obtained, the fluctuation was increasing proportionally when frequency of driver motor was increased.

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Pulsatile Pressure Distribution on the Snubber of Reciprocating Compressor (왕복동식 압축기의 스너버내 맥동압 분포)

  • Lee, Gyeong-Hwan;Rahman, Mohammad-Shiddiqur;Chung, Han-Shik;Jung, Hyo-Min
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.606-611
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    • 2007
  • Pulsation is an inherent phenomenon in reciprocating compressors. It interacts with piping to cause vibrations and performance problems. Indiscriminately connecting to a compressor can be dangerous and cost money in the form of broken equipment and piping, poor performance, inaccurate metering, unwanted vibration, and sometimes noise. Piping connected to a compressor can materially affect the performance and response. To minimize these detrimental effects, reciprocating compressor system should be equipped by pulsation suppression system. This study discusses pressure pulsation phenomena occurred in a reciprocating compressor system. An experiment applied air compressor unit, as pulsating pressure generator, has been done. The compressor was connected sequentially to a snubber model and pressure tank. Sensor probes were placed on the inlet and outlet pipes of snubber. Compressor was driven by a motor controlled by a frequency regulator. The experiment was conducted by adjusting the regulator at 40Hz. General information about an internal gas flow can be achieved by numerical analysis approach. Information of the velocity, pressure and turbulence kinetic energy distribution are presented in this paper. Based on this result, the design improvement might be done.

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