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이창민(Chang-Min Lee),윤린(Rin Yun),문현만(Hyeun-Man Moon),송윤석(Yoon-Seok Song),최동규(Dong-Guo Choi) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.5
MVR의 경우 압축과정을 폴리트릭픽과정으로 가정하여 이론적 모델링을 수행하였고, 그 성능은 제작사에서 제공된 성능곡선을 사용하여 평가하였다. TVR의 해석 및 설계에 있어서는 노즐과 디퓨저를 포함한 내부에 유체유동에 대한 보존방정식을 적용하여 분석하였다. 이를 통해 노즐과 목, 그리고 디퓨저의 크기를 결정할 수 있었다. MVR와 TVR의 이론적 모델링은 3개회사의 설계자료와 그 성능 및 에너지 및 질량수지를 비교하여 검증하였고, 본 모델의 실용적 적용을 위해 GUI 설계 툴을 개발하였다. 본 툴을 활용해 MVR과 TVR의 물질 및 에너지수지와 이들의 세부 설계규격을 결정할 수 있다. The MVR was theoretically modeled by assuming the process as the polytropic process, and the performance of the MVR was estimated by using the performance-curve provided by the manufactures. The TVR was investigated by applying the conservation equations to the movement of the fluids inside the TVR. The size of the nozzle and diffuser can be determined. The theoretical MVR and TVR modeling was verified by comparing the results from the model with the available design data. Besides, the GUI program was developed for the practical usage of the modeling. The mass and energy balance information, and the specifications for the MVR and TVR can be available by using the GUI tool.
曺洸鉉 인제대학교 1992 仁濟醫學 Vol.13 No.3
1986년 9월 부터 1991년 2월까지 본 교실에서 실시된 139례의 판막치환 수술 환자 중 25례(18.0%)가 2중 판막치환 수술(MVR, AVR)환자였다. 술후 조기 합병증은 10례(40.0%)에서 발생하였고 조기사망은 4례(16.0%)발생하였는데 합병증의 대부분은 저심박출증(7례)이었고 조기 사망의 원인은 저심박출증(1례), 심장파열(1례), weaning failure(1례) 및 급성 심정지(1례) 등이었다. 술후 생존자 21례(84.0%)의 술후 추적기간은 평균 38.3±19.0개월(67 환자-년)이었으며 추적기간 중 후기 사망 밑 합병증(혈색전증)은 각각 1례(1.4±1.4%/환자-년)에서 발생하였다. A 5-Year- experience of combined aortic and mitral valve replacement(double valve replacement : DVR ) was reported. Between Sep. 1986 and Feb. 1992, 25 patients were received such operations. There were 13 males and 12 females ranging in age from 19 to 53 years with the mean age of 38.5±10.0 years. The results were summarized as follows. 1.The aortic clamping times(ACT) were ranging from 124 minutes to 221 minutes with the mean ACT time of 174±24.6 minutes. The total bypass times(TBT) were ranging from 147 minutes to 251 minutes with the mean TBT of 200.0± 26.1 minutes. 2.Preoperatire NYHA functional classes of patients were II (3 cases), III (15cases), IV (7 cases), and postoperatively 21 cases were improved to I (10 cases), II (11 cases). 3.All were rheumatic hear diseases. In mitral sites, stenosis was dominated in 17 cases and regurgitation was dominated in 8 cases. In aortic sites, stenosis was dominated in 15 cases and regurgitation was dominated in 10 cases. 4.Left atrial thrombus was noticed in 3 cases(12.0%) and valve calcification was noticed in 10 cases(40.0%). Combined tricuspid regurgitation was noticed in 7 cases(28.0%), and in which DeVega annuloplasty was applied. 5.St. Jude Medical valves(18 cases) and Carpentier-Edward valves(7 cases) were used. 29mm(9), 31mm(8), 33mm(6), 27mm(2) were used in MVR. 23mm(8), 21mm(8), 19mm(8), 27mm(1) were used in AVR. There were valve combinations such as M(33mm)-A(23mm), M(29mm)-A(19mm), M(29mm)-A(21mm), M(31mm)-A(19mm) and others with the case number as 4, 4, 3, 3, and 13 in the order of description. 6.Early postoperative complications were occurred in 10 cases(40.0%) and the early postoperative deaths were occurred in 4 cases(16.0%) with bypass weaning failure(1 case), LOS(1 case), cardiac rupture(1 case), sudden cardiac arrest(1 case). 7.Mean follow-up time of survival 21 cases was 38.3±19.0 months(67 pt. years). Late postoperative complication was occurred in one case(thromboembolism) and the late postoperative death was also occurred in one case (non cardiac death). Therefore complication occurrence rate was 1.4±1.4% / pt-years and 5 year actual survival rate was 83.4±14.2%.
이창민(Chang-Min Lee),윤린(Rin Yun),문현만(Hyeun-Man Moon),송윤석(Yoon-SeoK Song),최동규(Dong-Guo Choi) 대한설비공학회 2010 대한설비공학회 학술발표대회논문집 Vol.2010 No.11
The theoretical modelling for designing of the MVR(mechanical vapor recompression) and the TVR(thermal vapor recompression) in the chemical process has been conducted in the present study. The steam compressing process in the MVR is modelled as the polytropic process, and the other losses for the bearing, sealing, and gear parts are all considered in calculating the actual power consumption. The designing of the nozzle in the steam jet ejector for the TVR is carried out by applying the model, which was developed through the conservation laws of mass and energy. The sizes of the ejector is determined by the semi-empirical models. This model is applied to design the actual sized MVR and the TVR in the chemical process.
이창민(Chang Min Lee),임정열(Jeong Yeol Lim),윤린(Rin Yun) 대한설비공학회 2015 설비공학 논문집 Vol.27 No.4
The MVR was theoretically modeled by performing the polytropic process, and the polytropic coefficient was estimated by using the performance curve provided by the manufacturers. The TVR was investigated by applying the conservation equations to the movement of fluids inside the TVR. The size of the nozzle and diffuser was determined. Theoretical MVR and TVR modeling was verified by comparing the results of the model with the available design data. Besides, the effects of multi-staging of the MVR on power consumption, and the effects of suction and primary pressure on the sizing of TVR were investigated.
폐수처리용 기계적 증기 재압축 터보 송풍기 개발에 관한 연구
김일겸,박우철,손상석,김용남 한국산학기술학회 2023 한국산학기술학회논문지 Vol.24 No.1
본 연구는 폐수처리용 MVR 터보 송풍기를 개발하기 위하여 CFD 해석을 수행하여 성능을 검토하였으며, 이를 실험 결과와 비교하였다. 유동에 대한 송풍기의 구조적 안정성에 대하여 검토하기 위하여 FSI 해석을 수행하였으며, 모드 해석을 수행하여 송풍기의 운전조건에 대한 동적 안정성을 검토하였다. 유동해석을 수행하여 개발하고자 하는 터보 송풍기의 운전조건에 적합한 임펠러의 blade 수는 Main blade가 16개이고, Splitter blade는 Main blade 중간에 1개인 것으로 나타났다. 효율은 해석값이 87.3%로 나타났으며, 실험값은 87.7%로 나타나, 실험값 기준으로 약 0.5 % 정도 작게 예측되었다. 유동-구조연성 해석 결과는 안전계수가 케이스는 약 2.1 이상이고 임펠러는 15 이상으로 나타났으며, 최대변위가 케이스는 약 1.05 mm이고 임펠러는 0.02mm로 나타나 구조적으로 안전한 것으로 판단된다. 모드 해석에 의하면 케이스와 임펠러의 1차 모드의 고유진동수는 각각 70.30 Hz와 142.67 Hz이다. 터보 송풍기 회전에 의한 가진 주파수는 53.63 Hz이므로 고유 진동수가 가진 주파수에 비하여 크게 나타나고 있어, 공진 현상에 대하여 안정적인 것으로 판단된다.
Design and fabrication of a new piezoelectric paper feeder actuator without mechanical parts
Shahryar Ghorbanirezaei,Yousef Hojjat,Mojtaba Ghodsi 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.24 No.2
A piezoelectric paper feeder actuator using Micro Virtual Roller (MVR) is proposed, designed, fabricated and tested. This actuator can drive a sheet of paper forward or backward without any mechanical parts, such as the costly and heavy rollers used in traditional paper feeders. In this paper feeder actuator, two vibrating stators which produce traveling waves are used to drive the paper. The vibrations of the stators are similar to those of piezoelectric motors and follow a similar procedure to move the paper. A feasibility study simulated the actuator in COMSOL Multiphysics Software. Traveling wave and elliptical trajectories were obtained and the dimensions of the stator were optimized using FEM so that the paper could move at top speed. Next, the eigenfrequencies of the actuator was determined. Experimental testing was done in order to validate the FEM results that revealed the relationships between speed and parameters such as frequency and voltage. Advantages of this new mechanism are the sharp decrease in power consumption and low maintenance.