• Title/Summary/Keyword: Temperature of supply oil

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Experimental Investigation on the Inlet Pressure Build-Up at the Entrance of a Large Tilting Pad Journal Bearing (대형 틸팅패드 저어널베어링의 패드 입구에서 발생하는 선단압력에 관한 실험적 연구)

  • 하현천;김경우;김영춘;김호종
    • Tribology and Lubricants
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    • v.9 no.2
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    • pp.22-28
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    • 1993
  • The experimental investigation on the inlet pressure of a large tilting pad journal bearing is studied. The continuous distribution of the film pressure and film thickness are measured along with the shaft speed and bearing load for various flow rates. Considerably large inlet pressure is observed at the entrance of each pad, especially lower pads. The inlet pressure increases with the increase of shaft speed as well as bearing load, but it is almost independent on the folw rate and the oil supply temperature. Because of the inlet pressure, the upper pads always keep up slight wedge film shape which are almost parallel to the journal surface, and spragging is not observed in the upper pads with no preload.

A Study on Thermal Characteristics of Biodiesel (바이오디젤의 열적특성에 관한 연구)

  • Bae, Byong-Mok;Lim, Woo-Sub;SaKong, Seong-Ho;Mok, Yun-Soo;Choi, Jae-Wook
    • Journal of the Korean Society of Safety
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    • v.25 no.6
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    • pp.92-97
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    • 2010
  • A study is conducted on thermal characteristics of biodiesel which is already being produced in many countries because of its stable supply of energy in non oil-producing countries and economical benefits against increasing oil price, and environment conservation. So biodiesel has been used as important energy source in the fuel fields and a mount of production has increased year by year. Therefore, it is very important to find out the thermal characteristics of biodiesel for ignition temperature, maximum pressure and thermal behavior. The purpose of this study is to compare on thermal characteristics of biodiesel, petroleum diesel and those mixtures. Also, the main study was performed by flash point testers and modified closed type of pressure vessel test (MCPVT). Based on the data of flash point and MCPVT, the ignition temperature and the maximum pressure of biodiesel was $182^{\circ}C$ and 40.1bar, and petroleum diesel was $54^{\circ}C$ and 29.8bar.

The Study of Synthetic Material Bush (Railko Bush) Application on Large Container Vessel (대형 컨테이너 선박의 합성수지계열 RAILKO BUSH 적용 연구)

  • Lim, Jae-Hun;Park, Kun-Woo;Kim, Kyung-Ho
    • Special Issue of the Society of Naval Architects of Korea
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    • 2008.09a
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    • pp.46-53
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    • 2008
  • Recently, the synthetic material stern tube bush has been applied by ship owner's requirement because the synthetic material has a merit. That is to say, when stern tube seal is damaged and sea water comes into stern tube, it can work without problem because of water lubricating property. However, the material also has a demerit of temperature rise problem when some factors meets on synthetic material, for example, not sufficient lubrication oil supply and not proper shaft alignment and so on. As known in the world, the RAILKO bush is rampant for synthetic material by some ship owner because of the above mentioned reason. However, the bush has several accidents on large container vessel. Unfortunately or fortunately our yard has a chance to apply the RAILKO bush owing to requirement of specific ship owner. Therefore, it is much more required to approach the accurate shaft alignment analysis. In line with this reason, we had a shaft alignment calculation considering hull deformation and hull flexibility (hull stiffness). Also, in the calculation, we had considered dynamic condition which is reflected he propeller thrust forces and moments and oil film stiffness on the shaft alignment calculation. According to he shaft alignment calculation, bearing slope was applied on the tern tube bush and was measured. The RAILKO bush should be applied the running in procedure according to maker's recommendation for performing the oil film on the bush surface. Finally, the vessels were delivered successfully without any problem with AILKO bush as shown on his paper.

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On the Improvement of the Combustibility of Waste Plastics used in Blast Furnace

  • Ban, Bong-Chan;Choi, Jin-Shik;Kim, Dong-Su
    • Proceedings of the IEEK Conference
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    • 2001.10a
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    • pp.751-754
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    • 2001
  • A possibility of using waste plastics as a source of secondary fuel in blast furnace has been of recent interest. The success of this process, however, will be critically dependent upon the optimization of operating systems. for instance, the supply of waste plastics must be reliable as well as economically attractive compared with conventional secondary fuels such as heavy oil, natural gas and pulverized coal. In this work, we put special importance on the improvement of the combustibility of waste plastics as a way to enhance energy efficiency in blast furnace. As experimental variables to approach this target, the effects of plastic particle size, blast temperature, and the level of oxygen enrichment were investigated using a custom-made blast model designed to simulate a real furnace. Lastly, the combustion efficiency of the mixture of waste plastics and pulverized coal was tested. The observations made from these experiments led us to the conclusion that with the increase of both blast temperature and the level of oxygen enrichment, and with the decrease of particle size, the combustibility of waste PE could be improved at a given distance from tuyere. Also it was found that the efficiency of coal combustion decreased with the addition of plastics; however, the combustion efficiency of mixture could be comparable at longer distance from tuyere.

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A Study of Performance Characteristics on Hybrid Heat Pump System with Solar Energy as Heat Source (태양열이용 하이브리드 열펌프시스템의 성능특성에 관한 연구)

  • Park, Youn-Cheol;Kim, Ji-Young;Ko, Gwan-Soo
    • Journal of the Korean Solar Energy Society
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    • v.27 no.1
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    • pp.47-54
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    • 2007
  • Interests on renewable energy are increased due to oil price and environmental problems aroused from the fossil energy usage. In this study, performances of a solar assisted hybrid heat pump system are analyzed by experimental method. The developed system could runs at two types of operating mode. When the storage temperature is higher than the set temperature, the stored hot water in storage tank is supplied to the load directly. On the other hand, when the storage temperature lower than the set temperature, the water inside of the storage tank is used as heat source of the heat pump. In this study, the system control temperature for the alternation of the operating mode is set to $40^{\circ}C$ of the storage tank outlet. As results, it is founded that the COP of the developed heat pump system shows between 3.0 and 3.5. It is resonable performance for the heating system with a renewable energy as secondary heat source. The solar collect used in this study could supplies heat to the storage tank at over 400 W/m2 solar intensity. If the irradiation is lower than the 400 W/m2, the circulation pump stored and it could not supply heat to the storage tank. It is found that the difference temperature between the outlet of the storage tank and collector is $3^{\circ}C$. Even though, the extended study should be conducted to get a optimum performance of the developed system with various operating condition and control strategies.

A Study on the Phase Bandwidth Frequency of a Directional Control Valve Based on the Hydraulic Line Pressure (배관 압력을 이용한 방향제어밸브 위상각 대역폭 주파수 측정에 관한 연구)

  • Kim, Sungdong;Lee, Jung-eun;Shin, Daeyoung
    • Journal of Drive and Control
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    • v.15 no.4
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    • pp.1-10
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    • 2018
  • Spool displacement of a direction control valve is the standard signal to measure the bandwidth frequency of the direction control valve. When the spool displacement signal is not available, it is suggested in this study to use the metering hydraulic line as an alternative way to measure - 90 degree phase bandwidth frequency of the hydraulic direction control valve. Dynamics of the hydraulic line is composed of inertia, capacitance, and friction effects. The effect of oil inertia is dominant in common hydraulic line dynamics and the line dynamics is close to a derivative action in a range of high frequency; such as a range of bandwidth frequency of common directional control valves. Phase difference between spool displacement and line load pressure is nearly constant as a valve close to 90 degree. If phase difference is compensated from the phase between valve input and pressure, compensated phase may be almost same as the phase of spool displacement that is a standard signal to measure phase bandwidth frequency of the directional control valve. A series of experiments were conducted to examine the possibility of using line pressure in to measure phase bandwidth frequency of a directional control valve. Phase bandwidth frequency could be measured with relatively high precision based on metering hydraulic line technique and it reveals consistent results even when valve input, oil temperature, and supply pressure change.

Development of Heating and Cooling System with Heat Pump for Nutrient Solution Bed In Greenhouse (열펌프를 이용한 양액베드 냉난방시스템 개발)

  • Kang, Geum-Chun;Kim, Yeong-Jung;Yu, Yeong-Seon;Baek, Lee
    • Journal of Biosystems Engineering
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    • v.27 no.6
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    • pp.565-572
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    • 2002
  • In order to control the root-zone temperature of greenhouse crops in the hydroponics at hot and cold season, heat pump system for cooling and heating was built and tested in this work. The system was air-to-water type and vapour compression type. The heating and cooling mode was selected by the four way valve. Capacity of the compressor was 3.75㎾ and heat transfer area of the evaporator and the condenser were 3.05㎡ and 0.6㎡, respectively. According to the performance test, it could supply heat of 42,360 to 64,372kJ/h depending on the water circulation rate of 600 to 1,500ℓ/h, respectively, when indoor air temperature was 10∼20$\^{C}$. COP of heat pump system was 3.0 to 4.0 in the heating mode. But, COP of the cooling mode was 1.3 to 2.1 at indoor temperature of 20∼35$\^{C}$. The feasibility test in the greenhouse the developed heating and cooling system was installed, showed that the heating cost of the developed system was only about 13% of that of the conventional heating system. The heating cost of the developed system was 367won/day(electric consumption 9.7㎾h/day), while that of the conventional system was 2,803won/day(oil consumption 7.7ℓ/day) at the same heating mode.

A Study on Development of Movable Mariculture System by Use of Deep Sea Water (I) (해양심층수 이용형 이동식 해상양식시스템 개발 (I))

  • Kim, Hyeon-Ju;Jung, Dong-Ho;Choi, Hark-Sun
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.10a
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    • pp.329-332
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    • 2003
  • Aquaculture have been important role to supply food resources for mankind. However, competitive power of domestic mariculture industry was declined due to increase of labor and feed expenditures, and quantity import of low-priced livefishes from the developing underdeveloped nations in North and South East Asia. Mass production and quality enhancement can be pointed out to overcome such an industrial environment in this decade. To meet these requirement, movable mariculture base remodeling feasible vessel of chemical tanker or crude oil carrier has been proposed for more advanced mariculture management system by using deep seawater from about 200m which is sustainablely clean, nutrient-rich and cold seawater. Deep seawater can be applied for control of seawater temperature for mariculture base and cultivation phytoplankton and seaweed as feed. Besides mariculture, strategic marketing can be implemented by raw water and ice of deep seawater. Feasibility of applying deep seawater was considered after evaluating general movable mariculture base and management system.

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Combustion Property of Biodiesel Fuel (바이오디젤 연료의 연소 특성)

  • Song, Young-Ho;Shin, Baeg-Woo;Ha, Dong-Myeong;Chung, Kook-Sam
    • Fire Science and Engineering
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    • v.23 no.4
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    • pp.19-24
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    • 2009
  • As the environmental pollution by the drastic increase of vehicles becomes one of the social major concerns, the method of reducing the harmful exhaust emission is being the subject of interest. Utilization of waste edible oil as a raw material for biodiesel production is helpful not only for the stable supply of raw materials but also costing down the biodiesel price. This study was conducted to examine the combustion and thermal characteristics with mixing ratio of biodiesel fuel. Flash points, fire points and autoignition temperature (AIT) were measured by using Tag closed cup, Cleveland open cup flash point tester and AIT apparatus. As the result, flash points, fire points and AIT increased with percentage of more contained biodiesel.

Extraction Method of Parameter of Self Excited Eddy Current Brake Using L-C Resonance and characteristic research (L-C 공진형 자여자 와전류 브레이크의 파라미터 추출 방법 및 특성연구)

  • Jeong, Taechul;Cho, Sooyoung;Ahn, Hanwoong;Jeong, Geochul;Park, Eung-Seok;Cho, Hyuntae;Lee, Ju
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.11
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    • pp.82-88
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    • 2015
  • In recent years, numerous studies have attempted to find and explore the auxiliary brake and the oil pressure type and electrical type are mainly used. However, the model proposed here is to self-excited eddy current brake. The advantage of this is it does not require an external power supply and can be produced to reduce the size than others. This self-eddy current brake consists of RLC circuit so resistance, inductance and capacitance value can be considered a fixed value. But, inductance and resistance value changes depending on the shape, temperature and magnetic alteration. Therefore, in this paper, the focal point is characteristic analysis according to the parameter variations. Also, using this result, this paper explains how to estimate the capacitance.