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R600a를 이용한 소형 2단압축 시스템의 성능특성에 관한 실험적 연구
김영헌(Youngheon Kim),주영주(Youngju Joo),김용찬(Yongchan Kim),서국정(Kookjeong Seo) 대한설비공학회 2006 대한설비공학회 학술발표대회논문집 Vol.2006 No.11
The application of a two-stage refrigeration cycle with small capacity into a household refrigerator are very limited in literature. This paper presents the performance of two-stage and single-stage with compressor rpm and compressor combinations, and operating conditions. Based on experimental data, a proper compressor rpm combination of two-stage was determined. When the temperature difference between the condenser and F-evaporator was large, the COP of two-stage was higher than that of the single-stage. Generally, the two-stage system showed better performance than the single-stage system. When the external load of the two-stage cycle was the same as that of the single-stage cycle, the increase of the temperature of R-evaporator, which corresponds to intermediate temperature of the two-stage cycle, can enhance the system efficiency. As the temperature of the R-evaporator increased by 5 , the COP increased by 0.2.
김영헌(Youngheon Kim),한용하(Yongha Han),김범진(Bumjin Kim),김현섭(Hyunsup Kim) 한국자동차공학회 2017 한국자동차공학회 부문종합 학술대회 Vol.2017 No.5
Recently, many engineers establish sub-system performance target. However crash safety performance target is not run to satisfy rather than other performance. The major cause is stochastic problem. Several crash assessments show lots of result even though under same condition. In this paper, we consider material and steel panel thickness scatter for robustness design using optiSLang. Base on LS-DYNA crash analysis, several design of crash box are built by FCM. As result of this paper process, the characteristic of crash box is founded and then robust-design of crash box is possible considering stochastic behavior.
김영헌(YoungHeon Kim),정의진(Ui-Jin Jung) 한국자동차공학회 2019 한국자동차공학회 부문종합 학술대회 Vol.2019 No.5
It is hard to make product which perfect satisfy both performance that has trade-off relation. Especially, performance of pedestrian injury in crash performance always has trade-off performance because of it needs reduce stiffness of vehicle component even though other performance need high stiffness. One of the difficult pedestrian injury is upper-leg that represent force and moment of femur and pelvis when it contact bumper cover, hood and head-lamps. Here trade-off relation occurred between upper-leg injury and body deflection of bumper cover that components need high stiffness for satisfy quality condition that avoid body deflection. Previous vehicle development process try to reduce bumper stiffness for upper-leg injuy first then bumper deflection is measured when proto product built if it is not satisfaction added stiffness design performed. In this paper, we try to reduce wasteful development process by 1) establish bumper deflection analysis method and 2)trade-off optimization analysis between bumper deflection and upper-leg injury.
R600a 냉매를 이용한 2단 압축 사이클의 압축기 조합에 따른 성능 특성
주영주(Youngju Joo),김영헌(Youngheon Kim),정현준(Hyunjoon Jung),김용찬(Yongchan Kim) 대한설비공학회 2006 대한설비공학회 학술발표대회논문집 Vol.2006 No.11
Hydrocarbon refrigerants have been used in household refrigerators. This paper presents the performance of a household refrigeration system with isobutane(R600a) as a refrigerant. A two-stage vapor compression cycle with parallel evaporators is more efficient than the single stage cycle. Performance characteristics were measured by modifying compressor arrangement using two BLDC reciprocating compressors. The heat capacity was determined by the temperature difference of secondary fluid, and also calculated by using enthalpy and mass flow rate at the inlet and outlet of the heat exchanger. The heat capacity is approximately 1.0㎾. For an optimal two stage cycle, the compressor speed varied from 1600 to 3800rpm and then optimum speed was determined. This paper represents the effect of compressor arrangement on the performance of the two-stage cycle with a variation of intermediate temperature.