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空氣流動中의 噴射가스 燃料의 擴散에 關한 實驗的 硏究 (Ⅰ)
朴涇錫,金錫魯 慶熙大學校 1989 論文集 Vol.18 No.-
The mixture formation process has a great, influence on the performance and exhaust gas characteristics in the direct injection engines, such as Hydrogen engines and Diesel engines. This paper presents a fundamental study on the mixing process of compound jets. In this experimental study, the tracers used are CO_2, H_2 and He. The average-velocity of the air injected is 3m/sec, 5m/sec, 8m/sec, and 10m/sec. To observe spreading behavior of gas fuel, the Schlieren apparatus was used to take a picture of the fluid density. Then the values of the potential core length(Z_P), the potential core length and the transient length (Z_t), and the visual extension angle (φ) were obtained by visualized photo-analysed. The visual extension angle is decreased irrelatively for variety of injected gas, and is increased with constant grade in the area transient jet is occured. Experimental parameters are the average injection velocity of the tracer and the average injection velocity of the air.
Sung-Jool Kim,Ho-Jin Choi,하만영,김석로,방선욱 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.4
The present study numerically solves the flow and thermal fields in the full geometry of heat exchanger modeling with frost layer presence on the heat exchanger surface. The effects of air inlet velocity, air inlet temperature, frost layer thickness, fin pitch, fin thickness,and heat exchanger shape on the thermo-hydraulic performance of a fin-tube heat exchanger are investigated. Heat transfer rate rises with increasing air inlet velocity and temperature, and decreasing frost layer thickness and fin pitch. Pressure drop rises with increasing air inlet velocity and frost layer thickness, and decreasing fin pitch. The effect of fin thickness on heat transfer and pressure drop is negligible. Based on the present results, we derived the correlations, which express pressure drop and temperature difference between air inlet and outlet as a function of air inlet velocity and temperature, as well as frost layer thickness.
냉장고 내 냉기순환용 축류홴에 의한 내부 블레이드-통과-주파수 소음 예측
이승엽(Lee, Seung-Yub),허승(Heo, Seung),정철웅(Cheong, Cheol-Ung),김석로(Kim, Seok-Ro),서민영(Seo, Min-Young) 한국소음진동공학회 2009 한국소음진동공학회 논문집 Vol.19 No.5
Internal aeroacoustics of an axial fan used for circulating cold air in refrigerators are computed by using the hybrid method where CFD, acoustic analogy and BEM techniques are utilized. The unsteady flow field around the axial fan is predicted by solving the incompressible RANS equations with the conventional CFD techniques. Then, main noise sources are extracted from this unsteady flow field predictions using Acoustic Analogy. Lastly, BPF noise generated from an axial fan are predicted using these modeled sources combined with the tailed Green function techniques, which are numerically solved by the BEM technique. This hybrid model is validated by comparing the prediction with the experiment. Then, parameter studies are carried out, which suggest a capability of the current method as a design tool for the low-noise of the current axial fan system in a refrigerator.
윤성준(Seong-Jun Youn),노유정(Yoo-Jeong Noh),김석로(Seok-Ro Kim),김지원(Ji-Won Kim) 대한기계학회 2014 大韓機械學會論文集A Vol.38 No.1
대형냉장고의 도어 힌지는 냉장고 도어의 개폐 동작을 원활하게 하고, 도어의 하중과 도어개폐로 인한 충격을 견디는 구조 안전성이 요구된다. 하지만, 도어 힌지는 복잡한 힌지 메커니즘과 민감한 구조 안전성으로 인해 설계 시 어려움이 많다. 본 논문에서는 스프링 응답 특성, 공간제약, 구조강도 성능을 만족하는 메커니즘을 설계하고, 메커니즘을 둘러싼 외부 프레임의 부피를 최소화하여 힌지의 생산단가를 절감하고자 한다. 이를 위해 PIDO(progress integration and design optimization) 기술을 이용하여 모든 설계절차를 자동화함으로써 설계의 효율성을 높이는 성과를 거두었으며, 최적화 결과 목표로 하는 힌지 메커니즘 성능과 구조안정성을 개선하면서 힌지 프레임 질량의 24%를 절감하였다. Door hinges of large refrigerators are required to ensure that the doors open and close smoothly in addition to supporting door weights and enduring the impact loads due to door opening and closing. However, door hinge design is difficult because of complex hinge mechanisms and sensitive structural safety. In this study, the mechanism satisfying the required spring response, space constraints, and structural strength is optimized, and the volume of the outer frame covering the hinge mechanism is minimized for reducing production costs. The entire design process is automated using the PIDO(Progress Integration and Design Optimization) technique, which achieves an efficient design process. Therefore, the frame mass is reduced to 24%, and the mechanism performance and structural stability are improved.
냉장고 가스켓 형상 변화에 따른 냉장고 열손실 저감 효과
하지수(Ji Soo Ha),정광수(Kwang Soo Jung),김태권(Tae Kwon Kim),김경호(Kyung Ho Kim),김석로(Seok Ro Kim) 대한설비공학회 2009 설비공학 논문집 Vol.21 No.5
The amount of heat loss of a refrigerator through the gasket is nearly 30% of total refrigerator heat loss. In this paper, quantitative evaluation analysis of heat loss through gasket is established with numerical heat transfer analysis. Extending the gasket shape to protect the heat loss from the gasket, power consumption is measured by using real refrigerator in a temperature and humidity chamber and suggest the gasket shape to reduce the heat loss. From the present result of the numerical simulation of heat transfer and experiment with varying gasket shape, we are able to reduce the heat loss about 20~40% by using extended gasket and the power consumption can be reduced about 5%.