• Title/Summary/Keyword: Liquid Nitrogen

Search Result 747, Processing Time 0.092 seconds

Development of Cryogenic Pump Test Facility (극저온 펌프 성능시험설비의 개발)

  • Kang, Jeong-Seek;Kim, Jin-Sun;Kim, Jin-Han
    • The KSFM Journal of Fluid Machinery
    • /
    • v.7 no.4
    • /
    • pp.47-52
    • /
    • 2004
  • Cryogenic pump test facility (CPTF) is designed and developed in KARI. Hydraulic and cavitation performance of pump and inducer in cryogenic environment can be measured. Working fluid is liquid nitrogen and operating temperature is $-197^{\circ}C$. Run tank, catch tank of liquid nitrogen and their pressurizing tank has been built and remote tank pressure control system are installed. Maximum power of driving motor is 320 kW and its maximum speed is 32000rpm. Cryogenic fluids and lubricating systems are effectively separated that long test times are acquired. Therefore hydraulic and cavitation performance can be measured accurately and effectively. Pre-cooling test of the facility was successfully accomplished. This facility will contribute greatly to the development of turbopump for KSLV.

Hydraulic Performance Test of a Turbopump Inducer using Liquid Nitrogen (액체질소를 이용한 터보펌프 인듀서의 수력성능시험)

  • Kim Jin-Sun;Hong Soon-Sam;Kim Jin-Han
    • The KSFM Journal of Fluid Machinery
    • /
    • v.9 no.4
    • /
    • pp.20-26
    • /
    • 2006
  • A cryogenic test facility has been developed to perform inducer and pump tests using liquid nitrogen. Performance tests of a turbopump in the maximum 50ton-thrust class can be performed with cryogenic fluid in the facility which operates at a temperature around -196oC with the rotational speed up to 30,000rpm To verify the reliability of the cryogenic pump test facility, hydraulic performance tests of an inducer were accomplished, and their results were compared with the result from a water test. The results confirm the reliability of the cryogenic test facility, and it is expected to contribute for on-going development of a turbopump for liquid rocket engines.

Dynamic Electrical Breakdown Characteristics of Liquid Nitrogen (액체 $N_2$의 동적 절연파괴 특성)

  • 김영석;정종만;곽민환;백승명;장현만;김상현
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • /
    • pp.359-362
    • /
    • 1998
  • Electrical breakdown characteristics of liquid nitrogen(LNd used as both coolant and insulator for high $T_c$ superconductor system is very important. This paper presents dynamic breakdown characteristics of liquid nitrogen by quench penomena of thermal bubble under high electric field. As the result, the breakdown mechanism of $LN_2$ depends on thermal bubble effect. The breakdown voltage decreases slightly with increasing heating. In the Electrode arrangement, electrical breakdown voltage of horizontal arrangement appears lower than that of vertical arrangement.

  • PDF

Test of The HTS Power Cable Cooling System (초전도케이블 냉각시스템의 냉각특성 시험)

  • 염한길;고득용;김익생;김춘동;김도형
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
    • /
    • /
    • pp.281-283
    • /
    • 2003
  • High temperature superconducting power cable requires forced flow cooling. Liquid nitrogen is circulated by a pump and cooled back by cooling system. Typical operating temperature range is expected to be between 65K and 80K. Subcooler heat exchanger uses saturated liquid nitrogen boiling on the shell side to subcool the circulating liquid nitrogen stream that cools the HTS cable. The paper describes performance tests of the cooling system. The test items are heat exchanging performance of subcooler. pressure drop between supply and return lines, heat transfer coefficient inside former, cable cryostat heat leak and simulation of electrical load of HTS cable.

  • PDF

Friction on the Tool-chip Interface Under Liquid Nitrogen Cooling (공구와 칩 사이에서의 Liquid Nitrogen의 마찰 효과)

  • Jun Seong Chan
    • Journal of the Korea Safety Management & Science
    • /
    • v.4 no.2
    • /
    • pp.237-249
    • /
    • 2002
  • A cutting fluid can improve machining quality and tool life by maintaining the tool toughness and by providing a lubrication effect to reduce the friction between the chip and tool interface. Although liquid nitrogen as an environmentally safe coolant has been widely recognized in cryogenic machining, its function as a lubricant is plausible due to its chemical inertness, physical volatility and low viscosity. Since a reduced friction is a direct witness of the lubrication effect from a tribological viewpoint, this paper presents an evaluation of the apparent friction coefficient on the tool-chip interface in cryogenic cutting operations to prove and characterize the lubricity of LN2 in cryogenic machining. The mathematical approaches have been formulated to derive the normal and frictional forces on the tool-chip interface for the oblique cutting tests.

Development of Cryogenic Turbopump Test Facility (극저온 터보펌프 성능시험설비의 개발)

  • Kang, Jeong-Seek;Kim, Jin-Sun;Kim, Jin-Han
    • 유체기계공업학회:학술대회논문집
    • /
    • /
    • pp.340-345
    • /
    • 2003
  • Cryogenic turbopump test facility(CTTF) is designed and developed. Hydraulic and cavitation performance of turbopump in cryogenic environment can be measured. Working fluid is liquid nitrogen and operating temperature is $-197^{\circ}C$. Liquid nitrogen run tank, catch tank and pressurizing tank has been built and remote tank pressure control system are installed. Maximum power of turbopump is 320kW and its maximum speed is 32000rpm. Cryogenic fluids and lubricating systems are effectively separated that long test times are acquired. Therefore hydraulic and cavitation performance can be measured accurately and effectively. This facility will contribute greatly to the development of turbopump for KSLV.

  • PDF

Dielectric Characteristics of HTS Cable (고온초전도 케이블의 유전 특성)

  • Kwag, Dong-Soon;Kim, Hae-Jong;Cho, Jeon-Wook;Seong, Ki-Chul;Kim, Sang-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • /
    • pp.64-68
    • /
    • 2002
  • According to the increasing power demand for the future construction of many underground cables will be required. However, construction of new ducts for power cables will be more difficult. Therefore, research work for realizing the high temperature superconducting(HTS) cable has advanced, where the development of electrical insulating system at cryogenic temperature is one of the major researches. For an electrical insulation design of HTS cable, it is important to understand not only breakdown but also partial discharge and dielectric loss($tan{\delta}$) in liquid nitrogen/paper composite insulation system. In this paper, we investigated breakdown characteristics in liquid nitrogen/paper composite insulation system for the application to HTS cable. And, we studied the breakdown characteristics of the multi-layer and butt gap of the insulation papers in liquid nitrogen. Also, we measured dielectric loss($tan{\delta}$) of the mini-model Cable made of TERLAM IPP.

  • PDF

Insulation Characteristics of the Model Cable for 22.9 kV Class HTS Power Cable

  • Kim, Hae-Jong;Seong, Ki-Chul;Cho, Jeon-Wook;Kwag, Dong-Soon;Cheon, Hyeon-Gweon;Kim, Sang-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • /
    • pp.542-543
    • /
    • 2005
  • In this paper, describes the fabrication and dielectric insulation characteristics experimental results of the model cable for the 22.9kV class HTS power cable. The model cable were tested with partial discharge(PD), AC and impulse withstand voltage in liquid nitrogen($LN_2$) and liquid nitrogen pressure. In these test results, PD inception stress and AC, impulse breakdown strength increase as the pressure of the liquid nitrogen increases.

  • PDF

Cryopreservation of Mulberry(Morus) Seeds in Liquid Nitrogen(L$N_2$) (건조 및 초저온 처리에 의한 뽕나무 종자의 장기 보존)

  • 최영철;류근섭;방혜선
    • Journal of Sericultural and Entomological Science
    • /
    • v.42 no.1
    • /
    • pp.1-5
    • /
    • 2000
  • To investigate the possibility of crypreservation of mulberry seeds in liquid nitrogen(LN$_2$), characteristics of the seeds were examined after picking mulberry syncarps and drying-heat treatment. Storage in LN$_2$has the potential of providing indifinite preservation of valuable seed germplasm. Determining the tolerance of seeds among given cultivars to LN$_2$cooling and subsequent rewarming is the first step to establishing the feasibility of LN$_2$storage. Seeds of 4 mulberry varities were treated to LN$_2$(-196$\^{C}$) for 24 hours after drying heat treatment. Seed moisture content of Daeryukppong was the highest. As moisture content of mulberry seed was below 1%, storage in LN$_2$was safe. And drying heat treatment for 60 minutes was suitable to prevent decreased germination rate and germination vigor of seeds. The seeds of Cheongilppong were unsuibable to cryopreserve in LN$_2$for longterm storage.

  • PDF

The Characteristics of Frequency Spectrum of Radiated Electromagnetic Waves with AC Discharge Progress in Liquid Nitrogen (액체 질소중 교류방전 진전에 따른 방사전자파의 주파수 스펙트럼 특성)

  • 박광서;윤대희;이상훈;이현동;김충년;최병주;김기채;이광식
    • The Transactions of the Korean Institute of Electrical Engineers C
    • /
    • v.52 no.3
    • /
    • pp.123-129
    • /
    • 2003
  • In this paper, a relationship between AC discharge progress and the radiated electromagnetic waves was investigated by measuring electromagnetic waves using a biconical antenna and a spectrum analyzer. The frequency spectrum of the radiated electromagnetic waves were measured at the atmospheric pressure in liquid nitrogen($LN_2$) during partial discharges progressed by AC high voltage in nonuniform electric field. Front the results of this study, a new method was introduced for measurement and analysis of the radiated electromagnetic waves with discharge progress in $LN_2$ Besides. according to the consideration of the mutual relation between frequency spectrum of the radiated electromagnetic waves and discharge progress, it was confirmed that detecting partial discharge and estimating discharge progress could be possible. It is considered that these results obtained from this investigation may be used as fundamental data for diagnosis and prediction of electric insulations about superconducting and cryogenic power equipments.