• Tribology and Lubricants
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• v.28 no.6
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• pp.278-282
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• 2012

Various bearings such as deep-groove ball bearings, angular-contact ball bearings, and roller bearings are used to support the load and to lubricate between the shaft and the housing. The bearings of potential rolling systems in a turbo pump are the deep-groove ball bearings as comparing with the bearings with rolling elements such as cylindrical rollers, tapered cylindrical rollers, and needle rollers. The deep-groove ball bearings consist of rolling elements, an inner raceway, an outer raceway and a retainer that maintain separation and help to lubricate the rolling element that is rotating in the raceways. In the case of water-lubricated ball bearings, however, fluid friction between the ball and raceways is affected by the entry direction of flow, rotation speed, and flow rate. In addition, this friction is the key factor affecting the bearing life cycles and reliability. In this paper, the characteristics of flow conditions corresponding to a deep-groove ball bearing are investigated numerically, with particular focus on the friction distribution on the rolling element, in order to extend the analysis to the area that experiences solid friction. A simple analysis model of fluid flow inside the water-lubricated ball bearing is analyzed with CFD, and the flow characteristics at high rotation speeds are presented.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.358-362
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• 2005

An effective control of the axial thrust of a turbopump is one of the critical issues for its operational stability. In order to assure the stability of a turbopump-type fuel pump for a liquid rocket engine, an axial thrust measurement system was developed and a series of axial thrust tests were performed in water environment. In the tests, the axial thrust of the fuel pump at the design flowrate satisfied the axial force condition of the bearing of the pump. Also, it was found that by using orifices with different geometries in the secondary flow passage the overall axial thrust of the pump could be controlled.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.151-156
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• 2001

Experimental frictional and wear characteristics of silicon graphite materials is studied in this paper. Those specimens are lubricated with high temperature and highly pressurized water to simulate the same operating condition for the journal bearing and the thrust bearing on the main coolant pump bearing in the newly developing nuclear reactor named SMART(System-integrated Modular Advanced ReacTor). Operating condition of the bearings is realized by the tribometer and the autoclave. Friction coefficient and wear loss are analyzed to choose the best silicon graphite material. Pin on plate test specimens are used and coned disk springs are used to control the applied force on the specimens. Wear loss ana wear width are measured by a precision balance and a micrometer. The friction force is measured by the strain gauge which can be used under high temperature and high pressure. Three kinds of silicon graphite materials are examined and compared with each other, and each material shows similar but different results on frictional and wear characteristics.

• Journal of the korean Society of Automotive Engineers
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• v.5 no.1
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• pp.9-16
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• 1983

흔히 자동차용 belt를 단순한 소모품으로 생각하여 대수롭지 않게 여기는 경향이 있으나 belt slip에 의한 동력의 손실은 매우 큰 것이며 특히 자동차용 belt에 있어서 그 중요성은 상당한 것이다. 왜냐하면 crankshaft에서의 중력이 belt를 통해서 water pump나 air compressor등에 전달되며 이때 동력전달이 제대로 안되는 경우에는 engine은 냉각수와 냉각팬에 의해 냉각이 되지 않아서 금방 고은소착 되기 때문이며, 또한 belt를 너무 조이는 경우에는 water pump bearing의 파손 등을 초래하기 때문에 belt의 정확한 길이 계산이 매우 중요하다. 그러나 이러한 중요성에도 불구하고 belt의 설계계산을 행하는 데는 많은 시간이 걸리며, 간혹 잘못 계산을 하는 경우에는 큰 문제가 발생할 수도 있기 때문에 belt계산의 기본이론식들을 전부 computer program 화하여 시간의 절약과 계산의 오류를 피하고자 한다. Program을 만들기 위해서 사용한 computer는 micro-computer로서 PET (Personal Electric Transactor)2001이며 사용한 언어는 BASIC이다.

• Tribology and Lubricants
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• v.11 no.1
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• pp.58-65
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• 1995

When marine lubricating oil began to be emulsified and oxidized through ingressive water that have leaked from cooling pump seal systems, cooler, purifier system and piping system, the cavitation erosion-corrosion in alloy metals of bearings remains to the various troublesome problem at effective engine performance. Therefore, applied the cathodic protection to the control test of cavitation erosion-corrosion, and appointed the marine system oil containing 3% sea water as test environments, with different conductibility. Also, used the piezoelectric vibrator with 20 KHz, 24 $\mu$m as the cavity generation apparatus, and examined the weight loss, potential value, current density etc. in specimens with those condition. According to this testing data, investigated influence of cathodic protection on the control characteristics of cavitation erosion-corrosion, and will serve those as an elementary design data of marine bearing.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.8-13
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• 2010

An effective control of the axial thrust of a turbopump is one of the critical issues for obtaining its operational stability. Axial thrusts of the fuel pump for the 75-ton class rocket engine under development were measured with water as a test propellant at a room temperature. According to the test results, the axial thrust of the fuel pump seemed to satisfy the axial force condition of its bearing. Also, the thrust was increased as a whole when the flowrate of the pump was decreased. Furthermore it was found that the thrust and the leakage flowate were modified when the gaps between the floating ring seals and the impeller were changed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.78-81
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• 2009

A series of hydraulic tests of a fuel pump are performed using water at a room temperature. The pump is under development for 75-ton class liquid rocket engines of the open-loop gas generator type. According to the test results, the fuel pump satisfies its design requirement and its head and efficiency at the design flowrate are higher than the expected value by the computational analysis. Also, it is found that the pressure at the rear bearing outlet is higher than expected because the inlet of bypass pipe line is narrow. Furthermore, the flowrate of the secondary flow is estimated using the pressure difference of the elbow of the bypass pipe line.

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.3
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• pp.1707-1718
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• 1969

The purpose of this experiment is to determine the relations between numbers, arrangements and pumping rates of wells. In this experiment, well pipes were vertically set up in an artificial water-bearing sand layer of homogeneous quality. Wells were arranged in different ways and their number was varied in order to observe the variation of pumping rates. Sands were filled in a square tank, $183cm{\times}91.5cm{\times}91.5cm$ so as to secure a water-bearing layer. Water was constantly supplied from a supply tank located at an end of the tank. The number of well pipes was varied from one to four. Well pipes were connected by a horizontal header pipes were connected by a horizontal header pipe located above them and one pump was used. Pumping rates were measured, when they were arranged in longitudinal and lateral directions, They were also arranged in a square and triangle. The main results thus obtained are presented as follows: (1) When well pipes are laid out in a longitudinal line, i. e., in a flow direction, the ratios of pumping rates of one-pipe well and wells 2-, 3- and 4- pipe t, are 1.903, 2.506 and 2.66, respectively. (2) When well pipes are laid out in a lateral line, i.e., in a perpendicular direction to flow, the same ratios as (1) are 1.912, 2.527 and 2.88. (3) When four pipes are laid out in a square and three pipes are laid out in a triangle, pumping rates are deereased, Comparing with the cases when pipes are laid out in a straight line.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.116-120
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• 2003

In general, industrial rotating machinery have been designed to have critical speed that is above operating speed. But nowadays, they should be operated more than the first critical speed as usual with the trend of high speed and high performance of rotating machinery. Therefore, it is important to predict the accuracy rotordynamic characteristics of the high speed rotating system in advance. In this paper, the results of rotordynamic analysis about FWP(Feed Water Pump) drive turbine rotor are showed. Because the FWP drive turbine analyzed is high speed machinery operated more than the operation speed of conventional FWP drive turbine, Seismic response analysis as well as unbalance response analysis is done in order to improve the reliability of the new turbine rotor-bearing system.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.10
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• pp.483-493
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• 2001

The 3-phase induction is used for the MCP(main coolant pump) and the pure water is used for lubrication of bearing because of the difficulty of repair. Therefore the type of motor is the canned-motor that is welded by sealed can to prevent the stator and rotor from the lubricating water. A lot of Eddy currents are produced in the can because of the conductivity of material. And these eddy currents in the can are the most important cause that decrease the efficiency of induction motor. Therefore we have to find the method to decrease these eddy currents in the can for the improvement of efficiency of motor. In this paper, we proposed the method of design and analysis of canned-motor using equivalent circuit with consideration of can loss for the improvement of efficiency of motor.