http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
90도 요철이 설치된 회전덕트에서 유출홀이 열/물질전달에 미치는 영향
박석환(Suk-Hwan Park),전윤흥(Yun Heung Jeon),김경민(Kyung-Min Kim),이동현(Dong-Hyun Lee),조형희(Hyung Hee Cho) 한국유체기계학회 2005 유체기계 연구개발 발표회 논문집 Vol.- No.-
The present study investigates the effects of bleed flow on heat/mass transfer and pressure drop in a rotating channel with transverse rib turbulators. The hydraulic diameter (Dh) of the square channel is 40.0 ㎜. The bleed holes are located between the rib turburators on leading surface and the hole diameter (d) is 4.5 ㎜. The square rib turbulators are installed on both leading and trailing surfaces. The rib-to-rib pitch is 10.0 times of the rib height (e) and the rib height-to-hydraulic diameter ratio (e/Dh) is 0.055. The tests were conducted at various rotation numbers (0, 0.2, 0.4), while the Reynolds number and the rate of bleed flow to main flow were fixed at 10,000 and 10%, respectively. The results suggest that the heat/mass transfer characteristics in the internal cooling passage are influenced by rib turbulators, bleed flow and the Coriolis force induced by rotation. For the rotating ribbed passage with bleed flow, the heat/mass transfer on the leading surface is hardly affected by bleed flow, but that on the trailing surface decreases due to the diminution of main flow. The results also show that the friction factor decreases with the bleed flow.
회전 사각유로 내 후연면에 유출유동이 열/물질전달에 미치는 영향
박석환(Suk Hwan Park),전윤흥(Yun Heung Jeon),김경민(Kyung Min Kim),이동현(Dong Hyun Lee),조형희(Hyung Hee Cho) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
The present study investigates the effects of bleed flow on heat/mass transfer in a rotating square channel with transverse rib turbulators. The bleed holes are located between the rib turbulators and are installed on leading or trailing surface. The tests were conducted under the conditions of various bleed flow rates (0%, 20%, 40%) and rotation numbers (0, 0.2, 0.4), where Reynolds number was fixed at 10,000. The results suggest that the heat/mass transfer characteristics in the internal cooling passage are influenced by rib turbulators, bleed flow rate and bleed hole location. The heat/mass transfer on the surface with bleed holes is more increased than that without bleed flow, while that on the opposition surface is a little decreased. It is because of the diminution of the internal flow. The results also show that effects of bleed flow is different according to bleed holes location.
상변화를 수반하는 항공용 블랙박스의 열특성에 관한 연구
박석환(Suk-Hwan Park),이병호(Byeong-Ho Lee),최지호(Ji-Ho Choi) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
Black Box records flight data such as airspeed, altitude, acceleration, voice data, etc. Each additional parameter that is recorded by the Black Box gives investigators one more clue about the cause of an accident. The present study investigates the thermal characteristic for Black Box of the material with phase change using Icepak 12.0. Heat absorption material and insulation materials are used to protect memory module in Crash Protected-memory Module from high and low temperature fire condition. The thermal analyses were conducted under the conditions of various Black Box sizes(75,95,115,135㎜), types(circle, square), and volume ratios(0.2,0.3,0.4,0.5) of heat absorption material. The results suggest that the thermal characteristics are influenced by Black Box size, type and volume ratio of heat absorption material. Also, the test was conducted to confirm thermal reliability of Crash Protected-memory Module of Black Box and the result passed.
신용석(Dong-Suk Shin),이영수(Young-Soo Lee),박해광(Hae-Kwang Park),박석환(Seok-Hwan Park) 한국컴퓨터정보학회 2009 한국컴퓨터정보학회 학술발표논문집 Vol.16 No.2
최근 장애인에 대한 사회적 배려 및 관심이 높아지면서 장애인을 위한 각종 보조기구가 많이 개발되고 있다. 대부분의 청각, 시각, 정아 장애인들은 정자, 수화 등을 통해 타인과의 의사소통이 가능하며, 또한 이들을 위한 많은 보조기구가 개발되어 큰 도움을 받고 있지만 척수 손상 환자들을 위한 보조기구는 전무한 실정이다. 이에 본 논문에서는 척수 손상 환자를 위해 들숨, 날숨 기반으로 각종 기기(컴퓨터, 휠체어, 콘센트 등)들을 작동시키며, 또한 입력된 분자를 음성으로 출력할 수 있는 시스템을 설계하고 구현하여 척수 손상 환자들이 최소한의 도움으로 독립적인 활동이 가능하도록 하였다.
유출유동을 가진 회전사각유로 내 열/물질전달에 45도 요철이 미치는 영향
전윤흥(Yun Heung Jeon),박석환(Suk Hwan Park),김경민(Kyung Min Kim),이동현(Dong Hyun Lee),조형희(Hyung Hee Cho) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11
The present study investigated the effects of channel rotation and bleed flow on heat/mass transfer in a square channel with 45° rib turbulators. The bleed holes were located between the rib turbulators on the leading surface and those on the trailing surface case by case. The tests were conducted under the conditions of various bleed ratios (0.0, 0.2, 0.4) and rotation numbers (0.0, 0.2, 0.4) at Re=10,000. The results suggested that heat/mass transfer characteristics were influenced by the Coriolis force, decrement of main flow rate, secondary flow by angled ribs and bleed hole location. As the bleed ratio (BR) increased, heat/mass transfer decreased on both surfaces due to the reduction of main flow rate. With increment of the rotation number, heat/mass transfer also decreased except the trailing surface with bleed holes because the reattachment of the secondary flow induced by angled ribs was weakened on the leading surface and the secondary flow was disturbed on the trailing surface by the Coriolis force.
각도요철 및 곡관부를 가진 회전덕트 내 압력강하 분포 (Ⅱ)
김경민(Kyung Min Kim),박석환(Suk Hwan Park),이동현(Dong Hyun Lee),조형희(Hyung Hee Cho) 대한기계학회 2006 大韓機械學會論文集B Vol.30 No.9
The present study investigates the pressure drop characteristics in rotating two-pass ducts. The duct has an aspect ratio (W/H) of 0.5 and a hydraulic diameter (Dh) of 26.67mm. Rib turbulators are attached parallel in the four different arrangements on the leading and trailing surfaces of the test ducts. The ribs have a rectangular cross section of 2mm(e) X 3mm(w) and an attack angle of 70°. The pitch-to-rib height ratio (p/e) is 7.5, and the rib height-to-hydraulic diameter ratio (e/Dh) is 0.075. The results show that the highest pressure drop among each region appears in the turning region for the stationary case, but appears in the upstream region of the second pass for the rotating case. Effects of parallel rib arrangements are almost the same in the first pass for the stationary and rotating cases. In the second pass, however, heat transfer and pressure drop are high for the cases with parallel NN or PP type ribs in the stationary ducts. In the rotating ducts, they are high for the cases with parallel NN or PN type ribs.
석탄가스화를 위한 중국산 저급 석탄의 광물학적 및 건조 특성
박종력 ( Chong Lyuck Park ),김병곤 ( Byoung Gon Kim ),전호석 ( Ho Seok Jeon ),김상배 ( Sang Bee Kim ),박석환 ( Suk Hwan Park ),이재령 ( Jae Ryeong Lee ) 한국광물학회 2010 광물과 암석 (J.Miner.Soc.Korea) Vol.23 No.3
석탄가스화는 청정석탄이용기술의 한 분야로 최근 국제 유가의 급격한 변동과 더불어 매우 각광을 받고 있는 기술이다. 본 연구에서는 중국 내몽고 지역의 저급석탄을 출발물질로 가스화를 위한 광학적 특성, X선 분광특성, X선 회절특성, 광물학적 특성, 건조특성 등을 분석하였다. 분석결과 석탄의 등급은 slagging성과 fouling성이 매우 낮으며 착화온도가 250℃ 정도인 brown coal인 것으로 조사되었고, 석영, 능철석, 점토광물 등이 주요 불순물로 혼재하는 것을 알 수 있었다. 또한 초기 수분이 28%로 매우 높기 때문에 이를 쉽게 건조하기 위한 방법으로 열풍건조와 마이크로웨이브 건조기술을 적용하여 비교한 결과, 마이크로웨이브를 이용한 건조가 좀 더 효과적인 것을 알 수 있었다. Coal gasification technology in the sector of domestic clean coal technologies is being into the limelight since recent dramatic rise of international oil price. In this study, we used a low rank coal from Inner Mongolia, China as a starting material for gasification. Various properties including optical, mineralogical, X-ray spectroscopic, X-ray diffraction, and drying property were measured and tested in order to estimate the suitability of the coal to gasification. The coal was identified as a brown coal of lignite group from the measurement of vitrinite reflectance. The coal has very low slagging and fouling potentials, and the ignition temperature is about 250℃. The major impurities consist of quartz, siderite, and clay minerals. Additionally, the coal had moisture content above 28%. Tests for finding effective drying method showed that the microwave drying is more effective than thermal drying.