• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.26-31
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• 2009

Three Lox pumps and one fuel pump are manufactured for turbopump real-propellent tests and water tests of the pumps are performed in order to estimate the performance characteristics of the pumps. According to the test results, the test region(flow ratio, cavitation number) of the pumps at the water tests cover the operating region at the real-propellent tests and also all the pumps satisfy the design requirement. The head of the Lox pumps shows a 2% difference among them due to the internal geometry, but the efficiency and overall cavitation performance are almost same. It is found that the fuel pump has a similar head and efficiency compared with the previous model of the same internal geometry, while it has a little inferior cavitation performance.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.145-151
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• 2016

In response to the cavitation caused by the partial vacuum caused by the fluid flow, a paint was developed by dispersing the lamella-shaped glass-flake in resin for anti-cavitation. This composite paint was developed by using the inorganic filler (lamella shaped glass-flake) and the NBR (Acrylonitrile-butadiene rubber) which was modified epoxy resin. Especially, the glass-flake was a thin film with a thickness of about 100~200 nm and length of about $20{\sim}30{\mu}m$, the aspect ratio was about 200 to 300 times that of the plate-shaped. So the paint for anti-cavitation have shown excellent performance in corrosion resistance. The results of evaluating anti-cavitation performance was below, tensile strength $4.8{\sim}6N/mm^2$ or more, rupture elongation 30% or higher, abrasive speed $10mm^2/h$ or less. In particular, it showed more than twice the superior performance compared to existing advanced foreign products in anti-cavitation performance evaluation.

• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.157-162
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• 2003

The sludge oils were produced necessarily in the ships operation, so that it will be the best way to manage the sludge oils inside ship itself from a viewpoint of the prevention of marine oil pollution from ship. The ultrasonic breaking systems which recycle the sludge oil from ship into usable oil to be brunt is recognized as a most possible recycling device. In this regards, the purpose of this study is to examine erosion damage on the SS400 specimen by cavitation and the effect of impact pressure generated from the demolition of the cavity of ultrasonic vibration in the marine sludge oil environment .. The erosion damage of specimen was investigated mainly on weight loss, weight loss rate and maximum erosion rate with variation of the oil temperature as well as the change of space between transducer horn and specimen. The experimental results showed that as the space between ultrasonic vibrator horn and specimen disk increased, the weight loss and weight loss rate decreased and the values were larger in SFO than in SLO. The experimental results can be useful to the development of sludge oil disposing systems and to consider a countermeasure for the prevention of erosion damages by cavitation.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.4
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• pp.48-54
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• 1995

A new propeller open water testing device is developed and tested in a tow tank. The devised dynamometer consists of a torque measuring part, a thrust measuring part and a driving motor with an RPM counter. Torque is designed to be measured directly from the torsion of the structure holding the motor by using strain gauges and, consequently, conventional slip ring is removed. Also, in order to make the device fit in relatively small model ships, the weight and the size of the whole integrated structure are reduced in various ways. The developed tester is proved to be easily utilized in small circulating water channel experiments and is believed to have provided us with essential information for future design of various types of conventional or object oriented force measuring device.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.194-194
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• 2010

The variable demand on the energy market, as well as the limited energy storage capabilities, requires a great flexibility in operating hydraulic turbines. But, present in Korea, the absence of testing laboratories and technical criteria for the performance test of small hydropower degrades the efficiency of the domestic hydropower machines, A performance guarantees for hydro turbines shall be contain, as a minimum, guarantees covering power, discharge and specific hydraulic energy, efficiency, maximum momentary overspeed and maximum momentary pressure and/or maximum steady-state runaway speed, as well as guarantees related to cavitation. Performance test are conducted by the test standard. Test codes based on extensive research data are written under the leadership of an IEC. Performance evaluation is carry out several test(performance test, cavitation test and runaway test). The paper presents the international turbine test laboratory and performance test standard.

• The KSFM Journal of Fluid Machinery
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• v.7 no.4 s.25
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• pp.47-52
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• 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.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.340-345
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• 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.

• Journal of Animal Environmental Science
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• v.17 no.3
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• pp.197-204
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• 2011

During the process of anaerobic digestion, hydrolysis of substrate is the key factor determining methane production efficiency. The hydrolysis efficiency are directly affected by biodegradability of substrate. In this study, three types of pre-treatment methods were tested to enhance biodegradability effectiveness. By the application of blender and the Cavitation treatment, the SCODcr increased from 24,723 mg/l to 24.726~29,175 mg/l and to 25,589~26,456 mg/l, respectively. In case of ozone treatment, the SCODcr decreased from 24,723 mg/l to 22.540~23,988 mg/l. In batch experiment, there was a little improvement of the biochemical methane potential (BMP) by the blender and the cavitation treatment. In contrast, the BMP somewhat decreased by ozone treatment. This result shows that higher anaerobic digestion efficiency of livestock manure could be obtained through pre-treatment of substrate.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.1
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• pp.31-37
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• 2023

In the present study, a method of performing cavitation erosion test directly on the anodized surface of the rudder model is proposed, not applying ink or paint on its surface. An image processing technique is newly developed to quantitatively evaluate the erosion damages on the rudder model surface after erosion test. The preprocessing saturation image, image smoothing, adaptive hysteresis thresholding and eroded area detection algorithms are in the image processing program. The rudder cavitation erosion tests are conducted in the rudder deflection angle range of 0° to -4°, which is used to maintain a straight course at the highest speed of the targeted navy ship. In the case of the conventional flat-type full-spade rudder currently being used in the target ship, surface erosion can occur on the model rudder surface in the above rudder deflection angle range. The bubble type of cavitation occurs on rudder surface, which is estimated to be the main reason of erosion damage on the rudder surface.

• Journal of Korea Ship Safrty Technology Authority
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• v.7
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• pp.27-37
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• 2001

소형 어선의 조업 환경을 개선하고자 하는 선주와 어민 입장에서 연안에서 번번히 발생하는 그물 걸림이나 충돌시 손상이 적은 추진장치를 저렴하게 공급받기를 원한다. 어선의 고속화 및 낚시전용선 개발 추제에 부응하여 어선용 소형 물제트 추진장치의 특성을 파악하고, 시스템의 개념 설계, 시제품 제작과 시운전 시험을 통하여 실용화 가능성을 검토하였다. 어선의 저항 감소, 캐비테이션 억제 등과 관련된 한계 기술을 개발하는 후속 연구가 진행되고 있다.