• 한국초전도ㆍ저온공학회논문지
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• 제13권2호
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• pp.25-28
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• 2011

A compact phase controller of pulse tube refrigerator is proposed in this paper. Most pulse tube refrigerators available now consist of a long inertance tube and reservoir as the phase controller. The long inertance tube and reservoir present a challenge for compact packaging in some applications. To overcome this disadvantage, the long inertance tube and reservoir are replaced with the compact phase controller consisted of mass, spring and damper in pulse tube refrigerator. This process is achieved using similarity of mechanical, electrical, and acoustic system and the specific configuration of the compact phase controller is designed. From the simulation code in this paper, the performance of pulse tube refrigerator with the designed compact phase controller is confirmed to be comparable to pulse tube refrigerator with the long inertance tube and reservoir.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1888-1891
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• 2003

In this paper, we proposed a new method to control the length of carbon nano tube in the single CNT probe. A single CNT probe was composed of a tungsten tip made by the electrochemical etching and carbon nano tube which was grown by CVD and prepared through the sonication. The two components were attached with the carbon tape. Since the length of CNT can not be controlled during the manufacturing, the post process is needed to shorten the CNT. In this paper, we proposed the method of electrochemical process. The process was done under the optical microscope and the results were checked by SEM. The diameter of the carbon nano tube used in this paper was about 130nm because the above process had to be done with the optical microscope. Using the method proposed in this paper, we can control the length of the nano tube tip.

• Journal of Advanced Marine Engineering and Technology
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• 제33권1호
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• pp.37-43
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• 2009

This paper is performed to develop a tripple-tube exchanger which can improve the system efficiency. Three different tube diameters are compacted by one body(tripple-tube) to recover waste heat from heat exchanging among the fluids. With this, the tripple-tube shows higher cooling capacity than the double-tube after comparing between those two systems. The results of this paper are basic data to design the optimum tripple-tube heat exchanger.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.401-411
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• 2003

Tube expanding process is for combining a heat-sink plate with hair-pins (Cu-tube) through plastic deformation. The two parts, i. e. , heat-sink plate and hair-pins are they components of a heat-exchanger for an air conditioner. This paper presents the analysis and dynamic modeling of a high-speed tube expander which integrates transfer of parts, fixing of parts, and tube expanding into one process. The 3-dimensional modeling of all the parts for the tube-expander was constructed using CATIA$\circledR$. then the CATIA$\circledR$ models are transferred into visuaINastran$\circledR$ to execute the 3-dimensional animation for checking prescribed cycle-time. The technique presented in this paper has been shown to be effective as a priori tool for verifying the design of a high-speed tube expander.

• 소성∙가공
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• 제9권6호
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• pp.604-614
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• 2000

In this paper, the mechanical characteristics and fundamental mechanism of a roll-formed tube during the hydroforming process are investigated in order to obtain the ewly localization of the tube hydroforming skills which are the core production techniques for the super light weight and high safety of the car body. Also, the theoretical influences of the material variables and the processes on the formability in the tube hydroforming are studied. In addition, the techniques to evaluate the forming limit of the bulging process of a tube are developed.

• Journal of Advanced Marine Engineering and Technology
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• 제25권2호
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• pp.344-350
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• 2001

This paper was studied on the characteristics of galvanic corrosion and its protection on heat exchanger tube plate in the sea water. In this paper, behavior of pitting corrosion of Ni-al bronze connected with Ti tube was measured af flow velocity of 0 m/s and 2.4 m/s. To protect galvanic corrosion, the protection characteristics of Ni-Al bronze connected with Ti tube by Zn-base alloys galvanic anode and hexagonal nylon insert was investigated. Main results obtained asre al follows: 1) The galvanic corrosion of Ni-Al bronze connected with Ti-tube is more active than single Ni-al bronze. 2) As the circuit resistance increase under the cathodic protection employing Zn-base alloys galvanic anode, Ni-al bronze connected with Ti tube is cathodically unpolarized. 3) The corrosion of Ni-Al bronze connected with Ti tube by nylon insert controls approximately 73% than not nylon insert.

• Journal of Advanced Marine Engineering and Technology
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• 제25권2호
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• pp.345-345
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• 2001

This paper was studied on the characteristics of galvanic corrosion and its protection on heat exchanger tube plate in the sea water. In this paper, behavior of pitting corrosion of Ni-al bronze connected with Ti tube was measured af flow velocity of 0 m/s and 2.4 m/s. To protect galvanic corrosion, the protection characteristics of Ni-Al bronze connected with Ti tube by Zn-base alloys galvanic anode and hexagonal nylon insert was investigated. Main results obtained asre al follows: 1) The galvanic corrosion of Ni-Al bronze connected with Ti-tube is more active than single Ni-al bronze. 2) As the circuit resistance increase under the cathodic protection employing Zn-base alloys galvanic anode, Ni-al bronze connected with Ti tube is cathodically unpolarized. 3) The corrosion of Ni-Al bronze connected with Ti tube by nylon insert controls approximately 73% than not nylon insert.

• 한국산학기술학회논문지
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• 제18권4호
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• pp.21-26
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• 2017

본 연구에서는 이중관형 열회수 환기장치의 제품 적용 가능성을 검토하기 위해 성능 시험을 수행하였으며 이중관의 내측관의 재질에 변경에 따른 검토를 하기 위해 종이관, 알루미늄관, 폴리머관을 제작하여 동일한 급/배기 풍량을 인가하여 측정하였다. 온도 교환 효율은 모든 경우에서 알루미늄관의 경우가 가장 큰 값을 나타냈으며 종이관과 폴리머관은 비슷한 결과를 보였다. 이는 내측관으로 사용된 재료의 열전도율과 두께의 차이 때문인 것으로 판단된다. 습도 교환 효율은 모든 경우에서 종이관의 경우가 가장 큰 값을 나타냈으며 알루미늄관과 폴리머관은 비슷한 결과를 보였다. 이는 종이 재질은 습도 교환이 가능하지만 알루미늄과 폴리머재질은 습도 교환이 불가능하기 때문인 것으로 판단된다. 습도 교환과 온도 교환의 두 값을 포함하는 전열 교환 효율은 종이관의 경우가 가장 큰 값을 나타냈으며 알루미늄관과 폴리머관은 비슷한 결과를 보였다. 에너지계수(COE)는 현열과 잠열교환이 동시에 일어나는 종이관의 경우 전열에너지계수 값을 현열교환만 일어나는 알루미늄관과 폴리머관은 현열에너지계수를 비교해 보면 종이관의 에너지계수가 가장 큰 값을 나타냄을 알 수 있었다. 본 연구를 통하여 이중관형 열회수 환기장치의 내부관 재질에 따른 성능을 비교 분석 하였으며 환기장치로 적용이 가능한 것을 알 수 있었다.

• 전기학회논문지
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• 제63권9호
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• pp.1180-1185
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• 2014

This paper describes the effects on SUS tube of power optical fiber composite cable on underground transmission lines. The effects on grounding, air gap between SUS tube and metal sheath, contact resistance between outer semi-conducting layer and metal sheath and grounding of SUS tube application or not are variously analysed using EMTP in normal operating condition as well as single line to ground fault. From these results, in this paper, the scheme for protecting the electrically abnormal phenomena will be established on power-optical fiber composite cable of underground transmission lines. This paper can contribute to specification of grounding reference of SUS tube of optical fiber composite power cable system.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2316-2321
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• 2008

This paper presents an improved performance of heat transfer for shell-and-tube and thermal analysis based on the Bell-Delaware method for single tube. Heat transfer has been compared for a smooth tube, helical tube and surface-coated tube. In general, the results showed that properly designed helical tube and surface-coated tube offer a significant improvement in heat transfer. The numerical results derived from the Bell-Delaware method for the shell-side heat transfer coefficient were verified with experimental results. The thermal analysis aids significantly in the solution of the design problem.