온도식팽창밸브의 전자식팽창밸브로의 대체 가능성에 관한 연구

한도영(Doyoung Han),정성욱(Seongwoock Jeong) 대한설비공학회 2006 대한설비공학회 학술발표대회논문집 Vol.2006 No.6

For the precise superheat temperature control of an air conditioner, an electronic expansion valve may be used instead of a thermal expansion valve. In this paper, technical and economical aspects of expansion valves were studied in order to find out the possibility to use an electronic expansion valve to replace a thermal expansion valve.

R32 냉매를 사용하는 히트 펌프의 전자식 팽창 밸브 질량유량 상관식 평가

김민규,정지환 대한설비공학회 2022 설비공학 논문집 Vol.34 No.7

The internal flow of an electronic expansion valve is complex. Many researchers have proposed mass flow correlations in various ways to predict the mass flow through an electronic expansion valve. However, the evaluation of the correlation equation was insufficient, and in this paper, data of the R32 heat pump system was acquired to evaluate correlations. The orifices of the electronic expansion valve used in the experiment were 2.40 mm and 1.65 mm, respectively. The acquired data were inputted into the existing correlation and compared. The correlational MAPE evaluated from the data of the electronic expansion valve with an orifice diameter of 2.40 mm was from 9.07% to 334.52%, SD showed from 4.34% to 206.37%. Correlated MAPE evaluated from the data of the electronic expansion valve with orifice diameter of 1.65 mm was from 24.07% to 160.82%, SD was from 6.00% to 177.11%. As a cause analysis, there is a difference in the geometric shape and size of the electronic expansion valve. Also, the change in physical properties depending on the refrigerant was one of the causes of the error. 지난 기간 동안 연구자들은 다양한 운전조건과 냉매에 대한 전자식 팽창 밸브 유량 상관식을 개발해왔다. 각자 다른 방식을 통하여 새로운 유량 상관식을 제시하였지만, 이에 대한 평가는 여전히 부족했다. 본 논문은 이러한 유량 상관식의 평가를 위해서 R32 냉매를 사용하는 히트펌프를 사용하여 넓은 운전조건과 내부 오리피스 지름이 다른 EEV를 사용하여 데이터를 취득하였다. 이 데이터를 이용하여 제시된 상관식에 적용하고 결과를 분석하였다. 현재까지 개발된 냉매 유량 상관식은 실험 데이터에 의존하기 때문에 제한된 운전 조건과 냉매, 전자식 팽창 밸브의 기하학적 조건에 영향을 받는다. 전자식 팽창 밸브의 내부 오리피스의 지름이 서로 다른 2개의 EEV에 대해서 실험한 데이터를 통해 비교한 결과 EEV #1(D: 2.40 mm)의 비교 결과는 Park et al.(10)의 상관식 평가결과가 MAPE 9.07%, SD 10.01%를 나타내어 가장 실험값과 유사하게 예측하였다. EEV #2(D: 1.65 mm)의 비교 결과는 Tian et al.(13)의 상관식 평가결과는 MAPE 24.07%, SD 10.21%를 나타내어 가장 실험값과 유사하게 예측하였다. 분석 결과 전자식 팽창 밸브의 기하학적 형상 및 수치의 차이와 냉매에 차이에 따른 운전조건 및 물성치의 차이로 인해 오차가 발생할 수 있다.

공기조화기용 팽창밸브의 구동특성

윤소남(So-Nam Yun),정병홍(Byeong-Hong Jeong),이근우(Kun-Woo Lee) 한국동력기계공학회 2007 한국동력기계공학회 학술대회 논문집 Vol.- No.-

An expansion valve for air conditioner is a type of flow control valve that is a combination of a stepping motor, reduction gears, a positioner and a poppet valve. The open area of the poppet valve is controlled by positioner which is also rotated in proportion to revolution of the stepping motor with reduction gears. In this study, the performance improvement strategies of the expansion valve for air conditioner were discussed. The effects of the nonlinearity and the hysteresis on the performance of the expansion valve were investigated through the experiment.

특수 압력용기용 안전밸브의 2중 구조로 디스크의 최적설계

김창호(Chang-Ho Kim) 한국기계가공학회 2007 한국기계가공학회지 Vol.6 No.4

A safety valve is used for protecting the pressure vessel and facilities by discharging the operating fluid into the valve from the accident when the pressure is over the designated value. The fluid is sulfurous acid and nitric acid. etc. in the semi-conductor assembly line. Thus the valve elements material must be acid resistance. Teflon, which is used generally as inner parts of a valve, tends to easily sticks to sliding surface by thermal expansion under high temperature. Some studies are performed to change teflon to another material and shape to have a better fluidity under the condition. The analysis of the thermal expansion is conducted by commercial FEM software to improve the problems. Boundary conditions were temperature and load in this study. From the analysis, the thermal expansion of stainless steel is verified to be lower than that of teflon under high temperature. Thus coupled teflon/stainless steel-made valve is applied to assembly line without danger due to thermal expansion.

열팽창을 고려한 특수 압력용기용 안전밸브 디스크의 설계에 관한 연구

강재원(Jae Won Kang),김창호(Chang Ho Kim),강동호(Dong Ho Kang) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

The safety valve is the important equipment used to protect the pressure vessel and pressure facilities from overpressure by discharging the operation medium when the pressure of system is reaching the design pressure of the system. Some materials for a safety valve disk are studied in this paper. A studied safety valve has to resist sulfurous acid and nitric acid. etc. Furthermore teflon which is a general material of the valve easily sticks to a disk and a sliding part of the valve by thermal expansion. Therefore both teflon and stainless-steel are used to improve these problems. The analysis of the thermal expansion is conducted with commercial FEM software to improve the problems. Boundary conditions were temperature and load in this study. From the analysis, the thermal expansion of by teflon/stainless steel-made valve is lower than that of teflon-made valve under high temperature. Thus, teflon/stainless steel-made valve is safe and no malfunction by thermal expansion.

에어컨용 팽창밸브 개발에 관한 연구

윤소남(S. N. Yun),함덕용(D. Y. Ham),한유리(Y. Han),정병홍(B. H. Jeong) 유공압건설기계학회 2008 유공압건설기계학회 학술대회논문집 Vol.2008 No.10

An air conditioner(air conditioning system) is a cooling equipment that has a the process of the one-cooling cycle such as compression, condensation, expansion and evaporation. Expansion process is operated by expansion valve that is a kind of mass flow control component. The characteristics of a expansion valve design parameters such as linearity, repeatability and hysteresis are very important because these parameters affect the variation of the COP(Coefficient of Performance). This paper presents the static and dynamic characteristics of a bellows type expansion valve. The static and dynamic analysis by experiments and the structure analysis by FEM tool were accomplished for development of the new structure of expansion valve. The torque characteristics of the stepping motor and the displacement variation of the poppet valve were also analyzed through the experimental setup. In this study, the new structure of the expansion valve through the theoretical analysis and experiment was suggested. And it was confirmed that the suggested model is proper to apply in the air conditioning system.

전자팽창밸브 작동특성에 대한 실험적 연구

윤소남 (Y. S. Nam),함덕용 (D. Y. Ham),한유리 (Y. Han),이근우 (K. W. Lee),정병홍 (B. H. Jeong) 한국동력기계공학회 2009 한국동력기계공학회 학술대회 논문집 Vol.2009 No.6

This study presents the possibility of the refrigerant control using electronic expansion valve which is operated by stepping motor. The electronic expansion valve is a type of flow control equipment that is a combination of a poppet, a positioner, three reduction gears and a stepping motor. The poppet modulates orifice its opening to maintain the controlled refrigerant flow. So, pitch control of the positioner and pulse control of the three reduction gears are very important design parameters for performance improvement of this study object valve. In this paper, the effects of the nonlinearity, the hysteresis on the performance and flow rate characteristics of electronic expansion valve were investigated. The input pulse of stepping motor, displacement characteristics and flow rate characteristics of this valve were analyzed through the experimental setup.

병렬팽창 냉동시스템의 성능실험에 관한 실험적 연구

구창대(Chang-Dae Koo) 한국산업융합학회 2011 한국산업융합학회 논문집 Vol.14 No.2

This study has been experimented about refrigeration capacity difference. It has been used 3 method, Manual expansion valve, thermostatic expansion valve and capillary expansion valve, and tested under the same condition by using the performance testing of parallel expansion. In temperature change of the temperature room, thermostatic expansion valve method displayed the most lower temperature, -18℃. In addition, the temperature, just before the expansion, also displayed the best result which was 4℃ lower than other expansion valve. In these results, it can be used for performance testing of parallel expansion refrigeration system.

백서에서 조직 확장기에 의한 정맥의 확장시 정맥 판막의 변화에 대한 실험적 연구

김준범,김잉곤 大韓成形外科學會 1995 Archives of Plastic Surgery Vol.22 No.2

Tissue expansion has been a known technique in plastic and reconstructive surgery for many years. In spite of the relatively widespread use of the tissue expansion technique, the venous valvular change following tissue expasion has received little attention in previous studies. If valvular changes can affect venous blood flow, the flap design after tissue expansion should be considered the direction of the valve. This is particularly true in the lower extremities because venous congestion might occur due to valvular incompetency. In the present study the saphenous veins of 32 rats were elongated using 5-cc tissue expanders which was underseated the leg adductor muscles. The expanders were overfilled with 20cc saline solution over an average period of 14 days and intraoperatively. The mean rate of elongation of the vessels was 34 percent, with a maximum gain of 61 percent. Histologically there was no reduction in vessel wall diameter or loss of intimal integrity. Subendothelial celluar proliferation was an indicator of this rapid regeneration.The gross and histological changes of the valve were not signficant. The valvular competency was not disturbed and the blood flow was not distrupted. Longitudinal elongation of the vessel using tissue expanders does not affect valves because the direction of the elongation is perpendicular to the direction of the valve and the elongation does not affect the luminal diameter of the vessels. Therefore, the result of this study suggests that the tissue expansion can be utilized with no concerning of venous valvular change.

SCR 시스템용 버터플라이 밸브의 형상개선에 관한 수치해석 연구

함선희(Sun Hee Ham),김학민(Hak Min Kim),염정국(Jeong Kuk Yeom) 대한기계학회 2021 大韓機械學會論文集B Vol.45 No.9

SCR(selective catalytic reduction)은 환원제를 촉매층에 통과시켜 배출가스의 질소 산화물을 선택적으로 질소와 산소로 환원시키는 방법이다. 본 연구는 SCR 시스템에 설치되는 고온용 버터플라이 밸브의 내부 변형을 수치해석을 통해 분석하였다. ANSYS Mechanical을 사용하여 수치해석을 진행하였고, 200A와 600A 크기의 버터플라이 밸브에 대해 내부 변형을 확인하였다. 수치해석 결과를 통해 버터플라이 밸브 200A의 오른쪽에서 최대 overlap인 0.64 mm가 발생하며, 버터플라이 밸브 600A의 왼쪽에서 최대 overlap인 2 mm가 발생하는 것을 확인하였다. 그 결과 열팽창이 디스크와 시트 링의 손상이나 고착을 발생시켜 밸브의 수명에 영향을 미칠 것으로 생각되며, 차후 열팽창을 고려한 밸브 형상의 설계 개선 연구를 진행할 필요가 있을 것으로 판단된다. Selective catalytic reduction (SCR) is a method of selectively reducing nitrogen oxides in exhaust gas to nitrogen and oxygen by passing a reducing agent through a catalyst layer. This study analyzed the internal deformation of the butterfly valve for high temperatures installed in the SCR system using numerical analysis. Numerical analysis was performed using ANSYS Mechanical, and the internal deformation of butterfly valves for 200A and 600A were confirmed. The numerical analysis results confirmed that a maximum overlap of 0.64 mm occurred on the right side of the butterfly valve for 200A, and a maximum overlap of 2 mm occurred on the left side of the butterfly valve for 600A. Therefore, thermal expansion is considered to affect the life of the valve by causing scratches or sticking to the disc and seat ring, and it is necessary to improve the design of the valve shape, considering thermal expansion.