• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.341-347
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• 2005

To perform a cryogenic development test for Tribo-elements in a turbopump, a cryogenic bearing and seal test facility (BSTF) is designed and currently under construction in KARI. The working fluid is liquid nitrogen operating at a temperature $-197^{\circ}C$. The maximum operating pressure and volume flow rate of BSTF are 100 bar and 10 liters per second, respectively. The development tests of floating ring seals, inter-propellant seals (IPS) and cryogenic ball bearings in a turbopump will be performed using the BSTF. This paper briefly described design requirements and procedures of BSTF.

• Tribology and Lubricants
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• 제36권5호
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• pp.253-261
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• 2020

In this paper, we present an experimental investigation of the frequency characteristics and a visual inspection of an oxidizer pump with a modified rear-floating ring seal for a 7-tonf turbopump. An oxidizer pump typically operates at high rotational speeds and under cryogenic conditions. Despite its low hydraulic efficiency, the floating ring seal is frequently employed as a leakage control solution for turbomachinery because it effectively reduces abrasion by friction. When the oxidizer pump starts up, the floating ring moves excursively but locks up stably against the pump casing when the contact pressure increases. The compressive force on the floating ring depends on the hydrodynamic forces induced by the flow through the floating ring. This force is controlled by the nose position of the floating ring. Based on a validation test for a 7-tonf turbopump with two types of floating rings, we concluded that the floating ring with a small diameter nose can move easily with a low contact pressure in the cooling path. This leads to instability of the pressure fluctuation around the floating ring. In contrast, a floating ring with a large diameter nose has a high contact pressure and attaches strongly to the casing, which causes wear and frictional oxidation between the contact surfaces of the impeller and the floating ring.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.347-351
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• 2004

The cryogenic test facility is developed for test of deep groove ball bearings, floating ring seals, materials (steel & copper) for High Pressure Turbopump of liquid rocket engine (LRE). The cryogenic bearing test is performed to evaluate the flow rate of cooling water and the load-carrying capacity of bearings. The cryogenic seal test is performed to evaluate the determination of magnitude of leakages through the seal, a time variation of this magnitude. The test of the materials Pair is performed to evaluate its fitness for operation in the liquid oxygen medium.

• 한국추진공학회지
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• 제24권6호
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• pp.61-68
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• 2020

7톤급 터보펌프 실매질시험에서 계측된 고주파 신호인 가속도와 압력섭동에 대한 주파수 분석(waterfall, frequency spectrum), 실효값(RMS) 계산 등의 신호 처리를 통해 산화제펌프의 신뢰성을 평가하였다. 계측된 압력섭동 신호 분석을 통해 산화제펌프의 누설 유로에 위치한 산화제 후방 플로팅 링에 의한 강한 압력섭동이 발생하였고 이는 산화제펌프 입구 및 출구 압력과 가속도 신호에도 영향을 주는 것을 확인하였다. 터보펌프의 가속도 실효값 계산을 통해 정격 운용 조건에서의 터보펌프는 양호한 진동 성능을 보여주고 있으며 가속도 회전수 성분 중 축계에 영향을 주는 회전수 동기 주파수 성분이 강하게 나타나는 것을 확인하였다.

• Tribology and Lubricants
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• 제20권4호
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• pp.183-189
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• 2004

The floating ring seal is used in an oxidizer and a fuel pump of the turbo pump unit in the liquid rocket engine to optimize a leakage without rubbing phenomenon. The damper floating ring seal, one of the floating ring seals, is with round hole pattern surfaces. It can reduce the leakage by increased friction factor that obtained from experimental data. In this paper, the leakage test about floating ring seal and damper floating ring seal was conducted. The test result showed the leakage performance of damper floating ring seal was better than the leakage performance of floating ring seal. With the leakage test the lock-up and rotation test about seal was conducted and that position is measured. The relatively large lock-up eccentric ratio was obtained from the test result of damping floating ring seal. The attitude angle of seal increases with increasing of shaft rotation.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.523-526
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• 2006

A series of hydraulic and cavitation tests are performed in water environment in order to verify the hydraulic and cavitation performance of three types of LOX pumps. All the performances of the pumps are found to be satisfied with each design requirement. In the hydraulic tests, the head and efficiency are increased as the gap between floating ring seals and the impeller shoulder is decreased. In the cavitation tests, some pumps show decrease in the cavitation performance as the flowrate of the pump is decreased.

• Tribology and Lubricants
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• 제24권3호
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• pp.140-146
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• 2008

The floating ring seal which is used in the high pressure turbo pump is frequently used in the oxidizer pump and the fuel pump of the turbo pump of the liquid propulsion rocket, because it is able to minimize clearance to decrease the leakage flow rate. But, the floating ring seal has a tendency to increase instability in decreasing eccentricity ratio. To complement this weakness, it is devised bump floating ring seal which is inserted bump in the outer surface. It has various experiment results. But the theoretical study of the bump floating ring seal didn't investigated yet. In this paper, we analyse about static characteristics of bump floating ring seal, compared previous experimental results. To analyze the characteristic of bump floating ring seal, we coupled perturbation method of floating ring seal and FEM of bump foil.

• Tribology and Lubricants
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• 제22권2호
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• pp.105-111
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• 2006

The floating ring seal which is used in the high pressure turbo pump is frequently used in the oxidizer pump and the fuel pump of the turbo pump of the liquid propulsion rocket, because it is able to minimize clearance to decrease the leakage flow rate. Compared with contact seal, the floating ring seal has advantage of minimizing clearance without rubbing phenomenon. But, the floating ring seal has a tendency to increase instability in operating condition in the high speed region. In this research, we devised floating ring seal which is inserted bump in the outer surface in order to improve the stability in the high speed region. Through this work, we expect to improve stability of floating ring seal with increasing the direct damping coefficient of seal and decreasing the eccentricity ratio.