• Title/Summary/Keyword: internal gas

Search Result 1,306, Processing Time 0.027 seconds

Performance Characteristics of Refrigerant R170(Ethane) Refrigeration System Using Liquid-gas Heat Exchanger (액-가스 열교환기를 이용한 R170(에탄)용 냉동시스템의 성능 특성)

  • Ku, Hak-Keun
    • Journal of Power System Engineering
    • /
    • v.20 no.5
    • /
    • pp.78-85
    • /
    • 2016
  • This paper considers the influence of internal heat exchangers to the efficiency of a refrigerating system using R170. These liquid-gas heat exchangers(internal or suction-line heat exchangers) can, in some cases, yield improved system performance while in other cases they degrade system performance. A steady state mathematical model is used to analysis the performance characteristics of refrigeration system with internal heat exchanger. The influence of operating conditions, such as the mass flowrate of R170, inner diameter tube and length of internal heat exchanger, to optimal dimensions of the heat exchanger is also analyzed in the paper. The main results were summarized as follows : the mass flowrate of R170, inner diameter tube and length of internal heat exchanger, and effectiveness have an effect on the cooling capacity, compressor work and RCI(Relative Capacity Index) of this system. Exception for the effect of inner diameter, the RCI of R170 with respect to refrigerant mass flowrate, the length and effectiveness of internal heat exchanger is about 2.1~3.3% higher than that of R13 at the same experimental conditions. With a thorough grasp of these effect, it is necessary to design the R170 compression refrigeration cycle using internal heat exchanger.

A Study on the storage of Fresh Fruits and Vegetables (Part II) Effects of Intercellular atmosphere and Ethylene evolution by control of external pressure and gas composition in Apple Fruits. (청과물 저장에 관한 연구(제 2보) -사과 저장에 있어서 환경압력 및 기체조성이 사과조직내 기체조성과 Ethylene 생성에 미치는 영향-)

  • 손태화;최종욱;서온수
    • Microbiology and Biotechnology Letters
    • /
    • v.1 no.1
    • /
    • pp.25-30
    • /
    • 1973
  • Experiments were carried out to clarify changes of intercellular gas composition, respiration and ethylene evolution by controlled external atmospheric pressure and external gas composition on apples. Jonathan apples, harvested 25, in September and Rolls apples, harvested 25, in October, 1971 and 1972 were used. Results obtained were as follows: 1. Intercellular gas volumes were proportionally changed by the given pressure, and the given pressure remarkably affected internal gas composition and volume of apples. As intercellular gas volumes were reached in their equilibrium within 5 min. after treatment, the internal atmospheric conditions became constant rapidly. 2. The increase of internal $CO_2$ production was co-related with an amount of internal $O_2$ consumption, therefore, the decreasing period of internal $O_2$ consumption was equalled to the period of climacteric rise in respiration. 3. The increasing of $CO_2$ production followed evolution of $C_2$H$_4$ and this phenomenon on SAP part. was subsequent to NAP part 4. In sub-atmospheric storage, CA effect was also obtained by control of low $O_2$ and high $CO_2$ concentration.

  • PDF

Production of Ultra-fine Metal Powder with Gas Atomization Processes

  • Wang, M. R.
    • Journal of ILASS-Korea
    • /
    • v.11 no.2
    • /
    • pp.59-68
    • /
    • 2006
  • Experimental results of the metal powder production with internal mixing, internal impinging and the atomizer coupled with substrate design are presented in this paper. In a test with internal mixing atomizer, mean powder size was decreased from $37{\mu}m\;to\;23{\mu}m$ for Pb65Sn35 alloy as the gas-to-melt mass ratio was increased from 0.04 to 0.17. The particle size further reduces to $16.01{\mu}m$ as the orifice area is increased to $24mm^2$. The micrograph of the metal powder indicates that very fine and spherical metal powder has been produced by this process. In a test program using the internal impinging atomizers, the mean particle size of the metal powder was decreased from $22{\mu}m\;to\;12{\mu}m$ as the gas-to-melt-mass ratio increased from 0.05 to 0.22. The test results of an atomizer coupled with a substrate indicates that the deposition rate of the molten spray on the substrate is controlled by the diameter of the substrate, the height of the substrate ring and the distance of the substrate from the outlet of the atomizer. This in rum determines the powder production rate of the spraying processes. Experimental results indicate that the deposition rate of the spray forming material decreases as the distance between the substrate and the atomizer increases. For example, the deposition rate decreases from 48% to 19% as the substrate is placed at a distance from 20cm to 40cm. On the other hand, the metal powder production rate and its particle size increases as the subsrate is placed far away from the atomizer. The production of metal powder with mean particle size as low as $3.13{\mu}m$ has been achieved, a level which is not achievable by the conventional gas atomization processes.

  • PDF

A Hydraulic and Feasibility Study of New Tower Internal in Gas Processing Plants

  • Choo Chang-upp
    • International Journal of Safety
    • /
    • v.3 no.1
    • /
    • pp.15-19
    • /
    • 2004
  • A new tower internal, which is called CSE, is presented. The CSE is composed of a nozzle perforated in its bottom along the entire periphery and equipped with a multi vane axial swirler at the inlet and hollow cylindrical separator at the outlet of the nozzle. According to the experimental work for obtaining the necessary hydraulic information of the CSE, which is used for preliminary design of a separation column, the CSE showed a stable operation over the wide rage of gas/liquid ratio. However, it caused large pressure drop due to the high gas velocity which should carry liquid droplets through the element. The high pressure drop may cause problems in energy recovery and the application of the CSE can be limited to the high pressure columns. Assuming that the tray efficiency of the CSE is the same with the existing separation columns, the results of the column design showed the size reduction of the column diameters by 30 to $40\%$ and investment cost saving, depending on operating conditions. The application of the CSE to separation column may also contribute to the de-bottlenecking the existing column.

Internal Pressure Variation Analysis and Actual Holding Time Test on ISO LNG Tank Container (LNG 탱크 컨테이너의 내부압력 변화 분석 및 실제 홀딩타임 측정)

  • Ryou, Young-Don;Lee, Jin-Han;Jo, Young-Do;Oh, Young-Sam;Cha, Kyong-Ho
    • Journal of the Korean Institute of Gas
    • /
    • v.17 no.6
    • /
    • pp.1-7
    • /
    • 2013
  • Internal pressure variation analysis and actual holding time test on ISO LNG tank containers which were made in Korea for the first time according to the special notification of ISO tank container manufacture have been conducted during the transport demonstration projects of the tank containers by tractor, train and ship. The internal pressure of the LNG tank container increased rapidly after LNG filling and dropped during moving the container. However, it was stabilized as time passed and followed the liquid-vapor equilibrium graph. In addition, actual holding time of the tank container was more than 20 days which was satisfied with the special notification of LNG tank container manufacture.

A Study on Site to Build Hydrogen Multi Energy Filling Station in Domestic LPG Station (국내 LPG 충전소 내 수소 융·복합충전소 구축 가능 부지 연구)

  • PARK, JIWON;HUH, YUNSIL;KANG, SEUNGKYU
    • Journal of Hydrogen and New Energy
    • /
    • v.28 no.6
    • /
    • pp.642-648
    • /
    • 2017
  • The use of fossil is causing enviromental all over the world. So hydrogen energy is attracting attention as one of the alternative. The government announced that 30% of the air pollution is because of the Internal Combustion Engine Vehicle. In addition, they plans to reduce Internal Combustion Engine Vehicles by 2030 and increase (electric vehicles, EV) or (fuel cell vehicle, FCV). The FCV is evaluated as a next-generation green car because it has a long driving distance and short charging time. However, the hydrogen industry is not able to expand due to the lack of refueling infrastrucutre. This paper predicts the site of hydrogen refueling stations for the expansion of the hydrogen industry and proposes a method to supply hydrogen multi energy filling stations.

A study on Greenhouse gas Emission Characteristics of Conventional Passenger and Hybrid Electric Vehicles (승용 및 하이브리드 자동차 온실가스 배출특성 연구)

  • Lim, Yun Sung;Mun, Sun Hee;Chung, Taek Ho;Lee, Jong Tae;Dong, Jong In
    • Journal of ILASS-Korea
    • /
    • v.25 no.1
    • /
    • pp.34-39
    • /
    • 2020
  • Automotive manufacturers are applying technologies for greenhouse gas reduction such as vehicle weight reduction, engine downsizing, direct injection technology, variable valves and transmission performance improvement to achieve the targets for enhanced greenhouse gas and fuel consumption efficiency. In this paper, compared and analyzed greenhouse emissions according to engine capacity, engine displacement, curb weight and sales volume of hybrid and internal combustion engine passenger vehicles. Hybrid emit 32~39% less greenhouse gas than internal combustion engines through the combined mode test method. Hybrid electric vehicle's curb weight was about 7% heavier on average for the same engine displacement, while greenhouse gas was about 36% lower. It was confirmed that in order to reduce the emission of pollutants of greenhouse gases as well as the air pollutants, it is necessary to expand the supply of eco-friendly vehicles.

Performance Analysis of R744 (Carbon Dioxide) Transcritical Refrigeration System Using Internal Heat Exchanger (내부 열교환기를 이용한 R744용 초임계 냉동사이클의 성능 분석)

  • Son, Chang-Hyo;Oh, Hoo-Kyu
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.33 no.4
    • /
    • pp.459-465
    • /
    • 2009
  • This paper considers the influence of internal heat exchangers to the efficiency of a refrigerating system. These internal heat exchangers(liquid-suction or suction-line heat exchangers) can, in some cases, yield improved system performance while in other cases they degrade system performance. A steady state mathematical model is used to analysis the performance characteristics of refrigeration system with internal heat exchanger. The influence of operating conditions, such as gas cooler pressure and evaporation temperatures, superheat in the evaporator and temperature of gas cooler outlet, to optimal dimensions of the heat exchanger is also analyzed in the paper. The main results were summarized as follows : the mass flowrate of R744, inner diameter tube and length of internal heat exchanger, and effectiveness have an effect on the cooling capacity, compressor work and RCI(Relative capacity index) of this system. With a thorough grasp of these effect, it is necessary to design the R744 compression refrigeration cycle using internal heat exchanger.

A Study on Drag Reduction Agency for Gas Pipeline

  • Zhang Qibin;Fan Yunpeng;Lin Zhu;Zhang Li;Xu Cuizhu;Han Wenli
    • Corrosion Science and Technology
    • /
    • v.7 no.5
    • /
    • pp.283-287
    • /
    • 2008
  • The drag reduction agency (DRA) for gas pipeline, a novel method used for reducing friction or drag on a gas flowing to increase the transmission efficiency of gas pipeline, is a more flexible and economical technology than internal flow efficient coatings. In this paper, an effective DRA has been developed in Authors' Institute by analyzing the hydrodynamic friction resistance on internal gas pipeline and then studying the work mechanism and molecular structure of DRA. In the meantime, a group of property test for selecting DRA material has been determined, including viscosity, contact angle, volatility, corrosion, slab extending, and flow behavior in horizontal tube. The inhibition efficiency and drag reduction efficiency of the developed DRA have been investigated finally based on the relevant test methods. Results of corrosion test show that the developed DRA has very good inhibition effect on mild steel by brushing a thin layer of DRA on steel specimens, giving inhibition efficiency of 91.2% and 73.1% in 3%NaCl solution and standard salt fog environment respectively. Results of drag-reducing test also show that the Colebrook formula could be used to calculate friction factors on internal pipes with DRA as the Reynolds number is in the range of $0.75\times10^5\sim2.0\times10^5$. By comparing with normal industrial pipes, the friction resistance coefficient of the steel pipe with DRA on internal wall decreases by 13% and the gas flux increases by 7.3% in testing condition with Reynolds number of $2.0\times10^5$.

A Study on the Method for Releasing the Internal Pressure of the Propane Cylinder caused by Liquid Expansion (액팽창을 고려한 프로판용기의 내압 해소방안에 대한 연구)

  • Yim, Sang-Sik;Jang, Kap-Man;Lee, Jin-Han;Park, Gi-Dong;Kim, Ki-Bum
    • Journal of the Korean Institute of Gas
    • /
    • v.19 no.5
    • /
    • pp.98-103
    • /
    • 2015
  • Liquefied petroleum gas can be charged up to 85% of cylinder volume by enforcement regulations of safety control and business of liquefied petroleum gas act. The charged mass by enforcement regulations is considered by liquid expansion of internal liquefied petroleum gas at $65^{\circ}C$. But the temperature of liquid would not be suspended under $65^{\circ}C$ in a cylinder or portable vessel at certain situation. In the thermodynamics view point, the cylinder can be exposed to high pressure by liquid expansion. Consequently, it can be possible to potential risk such as physical explosion. Hence, this paper will offer a method of estimated internal pressure by liquid expansion at critical state in the closed system. Also, the structural factor which is given rise to volume increasement of cylinder is offered by experiment. This paper is expected as crucial reference for a cylinder design of liquefied petroleum gas.