고주파 가열 장비를 활용한 터빈로터 휨 교정수식모델 개발

박준수,현중섭,박현구,박광하,Park, Junsu,Hyun, Jungseob,Park, Hyunku,Park, Kwangha 한국전력공사 2021 KEPCO Journal on electric power and energy Vol.7 No.2

The turbine rotor, one of the main facilities in a power plant, it generates electricity while rotating at 3600 RPM. Because it rotates at high speed, it requires careful management because high vibration occurs even if it is deformed by only 0.1mm. However, bending occurs due to various causes during turbine operating. If turbine rotor bending occurs, the power plant must be stopped and repaired. In the past, straightening was carried out using a heating torch and furnace in the field. In case of straightening in this way, it is impossible to proceed systematically, so damage to the turbine rotor may occur and take long period for maintenance. Long maintenance period causes excessive cost, so it is necessary to straighten the rotor by minimizing damage to the rotor in a short period of time. To solve this problem, we developed a turbine rotor straightening equipment using high-frequency induction heating equipment. A straightening was validated for 500MW HIP rotor, and the optimal parameters for straightening were selected. In addition, based on the experimental results, finite element analysis was performed to build a database. Using the database, a straightening amount prediction model available for rotor straightening was developed. Using the developed straightening equipment and straightening prediction model, it is possible to straightening the rotor with minimized damage to the rotor in a short period of time.

사우디 라빅발전소 터빈 블레이드 파손 분석기술 현장 적용

박준수,Park, Jun Su 한국전력공사 2021 KEPCO Journal on electric power and energy Vol.7 No.1

한전에서 운영중인 사우디라빅발전소에서 저압터빈 블레이드가 파손되었다. 블레이드의 경우 터빈의 핵심부품으로서 증기를 활용하여 발전기를 회전시켜 전기를 생산하는데 필수 부품이다. 반복적인 사고발생을 예방하기 위해 조직분석, 운전신호 분석등을 활용하여 원인을 규명하였고, 대책을 제시하였다.

전항력을 이용한 회전 블레이드 냉각성능 향상 방안 연구

박준수,Park, Jun Su 한국교통대학교 융복합기술연구소 2016 융ㆍ복합기술연구소 논문집 Vol.6 No.1

The serpentine internal passage is located in turbine blade and it shows the variety heat transfer distribution. Especially, the Coriolis force, which is induced by blade rotation, makes different heat transfer distribution of the leading and trailing surfaces of serpentine internal passage. The different heat transfer is one of the reasons why the serpentine cooling passage shows low cooling performance in the rotating condition. So, this study tried to design the advanced the serpentine passage to consideration of the Coriolis force. The design concept of advanced serpentine cooling is maximizing cooling performance using the Coriolis force. So, the flow turns from leading surface to trailing surface in advanced serpentine passage to match the direction of Coriolis force and rotating force. We performed numerical analysis using CFX and compared the existing and advanced serpentine internal passage. This design change is induced the high heat transfer distribution of whole advanced serpentine internal passage surfaces.

패스 트랜지스터에 바디 구동 기술을 적용한 저면적 LDO 레귤레이터

박준수,유대열,송보배,정준모,구용서,Park, Jun-Soo,Yoo, Dae-Yeol,Song, Bo-Bae,Jung, Jun-Mo,Koo, Yong-Seo 한국전기전자학회 2013 전기전자학회논문지 Vol.17 No.2

본 논문에서는 패스 트랜지스터에 바디 구동 기술을 적용하여 면적을 감소시킨 LDO (Low drop-out) 레귤레이터를 제안하였다. 바디 구동 기술은 트랜지스터의 문턱전압 (Vth)을 감소시켜 드레인 전류를 증가시켜 전류 구동 능력을 향상시킨다. 본 논문에서는 LDO 레귤레이터의 패스 트랜지스터에 바디 구동 기술을 적용하여 면적을 감소시키고, 기존 LDO 레귤레이터와 동일한 성능을 유지하였다. 본 논문에서 제안하는 패스 트랜지스터는 동일한 성능 대비 면적은 5.5 % 감소 하였다. 본 논문에서 제안하는 LDO 레귤레이터는 2.7 V ~ 4.5 V의 입력 전압, 1.2 V ~ 3.3 V의 출력전압 범위를 가지며, 150 mA의 출력 전류를 공급한다. Small area LDO (Low drop-out) regulator with pass transistor using body-driven technique is presented in this paper. The body-driven technique can decrease threshold voltage (Vth) and increase the current ID flowing from drain to source in current. The technique is applied to the pass transistor to reduce size of area and maintain the same performance as conventional LDO regulator. A pass transistor using the technique can reduce its size by 5.5 %. The proposed LDO regulator works under the input voltage of 2.7 V ~ 4.5 V and provides up to 150mA load current for an output voltage range of 1.2 V ~ 3.3 V.

충북 및 충주 지역의 수소산업 생태계와 가능성

박준수,Park, Jun Su 한국교통대학교 융복합기술연구소 2019 융ㆍ복합기술연구소 논문집 Vol.9 No.1

The government has designated the hydrogen industry as one of the three most innovative industries and is making a lot of investment and support. Chungcheongbuk-do and Chungju are developing strategies to foster local industries in line with these government policies. Hyundai Mobis's Chungju plant, located in Chungju, is the only fuel cell plant in Korea and is emerging as the center of hydrogen cars as the government's hydrogen mobility industry expands. Chungcheongbuk-do and Chungju City seek to attract relevant institutions and companies based on their regional strengths. In this paper, the current status of hydrogen industry in Chungcheongbuk-do and Chungju-si is discussed and future plans are discussed.

SLS 3D 프린터를 이용하여 제작된 PA2200의 단축 반복 인장하중에 따른 피로 특성에 관한 연구

박준수,정의철,최한솔,김미애,윤언경,김용대,원시태,이성희,Park, Jun-Soo,Jeong, Eui-Chul,Choi, Han-Sol,Kim, Mi-Ae,Yun, Eon-Gyeong,Kim, Yong-Dae,Won, Si-Tae,Lee, Sung-Hee 한국금형공학회 2020 한국금형공학회지 Vol.14 No.1

In this study, the fatigue behavior and fatigue life characteristics of PA2200 specimens fabricated by SLS 3D printer were studied. Fatigue tests were performed according to the standard specification (ASTM E468) and fatigue life curves were obtained. In order to perform the fatigue test, mechanical properties were measured according to the test speed of the simple tensile test, and the self-heating temperature of the specimen according to the test speed was measured using an infrared temperature measuring camera in consideration of heat generation due to plastic deformation. There was no significant difference within the set test speed range and the average self-heating temperature was measured at 38.5 ℃. The mechanical strength at the measured temperature showed a relatively small difference from the mechanical strength at room temperature. Fatigue test conditions were established through the preceding experiments, and the loading conditions below the tensile strength at room temperature 23 ℃ were set as the cyclic load. The maximum number of replicates was less than 100,000 cycles, and the fracture behavior of the specimens with the repeated loads showed the characteristics of Racheting. It was confirmed that SLS 3D printing PA2200 material could be applied to the Basquin's S-N diagram for the fatigue life curve of metal materials. SEM images of the fracture surface was obtained to analyze the relationship between the characteristics of the fracture surface and the number of repetitions until failure. Brittle fracture, crazing fracture, grain melting, and porous fracture surface were observed. It was shown that the larger the area of crazing damage, the longer the number of repetitions until fracture.

풍화대 지반에서의 쉴드 TBM 커터도구 선정 및 마모량 평가 (서울지하철 7호선연장 703공구 건설공사를 중심으로)

박준수,도덕수,김용일,정두석,Park, Jun-Su,Do, Deok-Su,Kim, Yong-Il,Jeong, Du-Seok 한국터널지하공간학회 2006 터널기술 Vol.8 No.3

제트홀이 설치된 핀-휜 및 핀-휜/딤플 복합 배열을 사용한 내부유로에서의 열전달 향상

박준수,Park, Jun Su 한국교통대학교 융복합기술연구소 2015 융ㆍ복합기술연구소 논문집 Vol.5 No.1

A Pin-fin array is widely used to enhance the heat transfer in the internal cooling passage. The heat transfer distribution around the pin-fin is varied by the horseshoe vortex and flow separation. The difference of heat transfer coefficient induces the large thermal stress, which is one of the major reasons to break of hot components. So, it is required to enhance the heat transfer on the back side of pin-fin to solve the thermal stress problem. This study suggests the pin-fin with inclined jet hole and complex pin-fin/dimple array to enhance the heat transfer on the back side of pin-fin. The heat transfer coefficient is predicted by the numerical analysis, which is performed by CFX 14.0. The numerical results are obtained at Reynolds number, 10,000. The results show that the heat transfer on the back side of pin-fin is increased in both cases. Beside, the wake, which comes from dimple and jet, helps to develop the horseshoe vortex and increase the heat transfer on the next row pin-fin.

하악피개의치에서 임플랜트의 식립각도에 따른 칸틸레버 길이의 감소효과가 응력분포 양상에 미치는 영향 -삼차원 유한요소법을 이용한 분석-

박준수,이성복,권긍록,우이형,Park, Jun-Soo,Lee, Sung-Bok,Kwon, Kung-Rock,Woo, Yi-Hyung 대한치과보철학회 2007 대한치과보철학회지 Vol.45 No.4

Statement of problem: Implant inclination and cantilever loading increse loads distributed to implants, potentially causing biomechanical complications. Controversy exists regarding the effect of the intentionally distal-inclined implant for the reduction of the cantilever length. Purpose: This study investigated the stress distribution at the bone/implant interface and prostheses with 3D finite element stress analysis by using four different cantilever lengths and implant inclinations in a mandibular implant-supported bar overdenture. Material and methods: Four 3-D finite element models were created in which 4 implants were placed in the interforaminal area and had four different cantilver lengths(10, 6.9, 4 and 1.5mm) and distal implant inclinations$(0^{\circ},\;15^{\circ},\;30^{\circ}\;and\;45^{\circ})$ respectively. Vortical forces of 120N and oblique forces of 45N were applied to the molar area. Stress distribution in the bone around the implant was analysed under different distal implant inclinations. Results: Analysis of the von Mises stresses for the bone/implant interfaces and prostheses revealed that the maximum stresses occurred at the most distal bone/implant interface and the joint of bar and abutment, located on the loaded side and significantly incresed with the implant inclinations, especially over $45^{\circ}$. Conclusion: Within the limitations of this study, it was suggested that too much distal inclination over 45 degrees can put the implant at risk of overload and within the dimension of the constant sum of a anterior-posterior spread and cantilever length, a distal implant inclination compared to cantilever length had the much larger effect on the stress distribution at the bone/implant interface.

ESD 보호 소자를 탑재한 Peak Current-mode DC-DC Buck Converter

박준수,송보배,유대열,이주영,구용서,Park, Jun-Soo,Song, Bo-Bae,Yoo, Dae-Yeol,Lee, Joo-Young,Koo, Yong-Seo 한국전기전자학회 2013 전기전자학회논문지 Vol.17 No.1

본 논문에서는 인덕터의 흐르는 전류를 감지하여 출력 전압을 일정하게 유지시키는 Peak Current-mode 방식의 DC-DC Buck Converter를 제안하고, 소신호 모델링에 기초하여 Power Stage 설계 방법과 시스템의 안정도를 설계하는 방법을 제안한다. 또한, dc-dc 컨버터의 신뢰성과 성능을 향상시키기 위해 보호회로를 추가하였다. 그리고 정전기 방지를 위하여 ESD 보호회로를 제안하였다. 제안된 보호회로는 게이트-기판 바이어싱 기술을 이용하여 낮은 트리거 전압을 구현하였다. 시뮬레이션 결과는 일반적인 ggNMOS의 트리거 전압(8.2V) 에 비해 고안된 소자의 트리거 전압은 4.1V 으로 더 낮은 트리거 전압 특성을 나타냈다. 본 논문에서 제안하는 회로의 시뮬레이션은 0.35um BCB 공정 파라미터를 이용하였고, Mathworks 사의 Mathlab과 Synopsys 사의 HSPICE 프로그램을 사용하여 검증하였다. In this paper, dc-dc buck converter controled by the peak current-mode pulse-width-modulation (PWM) presented. Based on the small-signal model, we propose the novel methods of the power stage and the systematic stability designs. To improve the reliability and performance, over-temperature and over-current protection circuits have been designed in the dc-dc converter systems. To prevent electrostatic An electrostatic discharge (ESD) protection circuit is proposed. The proposed dc-dc converter circuit exhibits low triggering voltage by using the gate-substrate biasing techniques. Throughout the circuit simulation, it confirms that the proposed ESD protection circuit has lower triggering voltage(4.1V) than that of conventional ggNMOS (8.2V). The circuit simulation is performed by Mathlab and HSPICE programs utilizing the 0.35um BCD (Bipolar-CMOS-DMOS) process parameters.