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평행한 두 사각유로를 연결하는 협소유로내의 난류유동 특성에 관한 대형 와 수치 모사
홍성호(Seong-Ho Hong),서정식(Jeong-Sik Seo),신종근(Jong-Keun Shin),최영돈(Young-Don Choi) 대한설비공학회 2008 대한설비공학회 학술발표대회논문집 Vol.2008 No.2
Turbulent flow characteristics on the gap of two parallel channels are investigated using LES(large eddy simulation) approach. Two parallel channels have the same cross-section area and are connected by the narrow channel named the gap. Turbulent flow near the gap makes the flow pulsation along the streamwise direction of two channels. The flow condition is the Reynolds number of 2.5× 10?? . We compared the predicted results with the previous experimental results and presented the axial mean velocity, turbulent intensities, Reynolds shear stresses and turbulent kinetic energy.
복합 부수로의 비정상 유동이 유발하는 난류열전달 증진에 대한 LES 해석
홍성호(Seong-Ho Hong),신종근(Jong-Keun Shin),최영돈(Young-Don Choi) 대한설비공학회 2011 설비공학 논문집 Vol.23 No.2
In the present article, we investigate numerically turbulent flow of air through compound rectangular channels. Large eddy simulation(LES) is employed for unsteady turbulence modeling. LES gives better predictions for the axial mean velocity distribution than those of other turbulent models. Strong large-scale quasi-periodic flow oscillations are observed in most of the geometries investigated. Such large-scale flow oscillations in compound rectangular channels are similar to the quasi-periodic flow pulsation through the gaps between fuel rod bundle in nuclear reactor. It exists in any longitudinal connecting gap between two flow channels. The frequency of this flow oscillation is determined by the geometry of the gap. The large scale cross motions through the rectangular compound channels induce significant heat transfer enhancement of the compound channel flow.
크기가 다른 단면을 가진 평행한 두 채널을 연결하는 협소유로의 맥동유동에 관한 수치해석
서정식(Jeong Sik Seo),홍성호(Seong Ho Hong),신종근(Jong Kuen Shin),최영돈(Young Don Choi) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
Flow pulsation in the gap connecting with two parallel channels is investigated by RANS and URANS approaches. The two parallel channels are connected by a small channel called for a gap. The parallel channels are designed to have different cross section area with its ratio of 0.5. Computations are conducted using a CFX 11.0 code. The bulk Reynolds number is 60,000. Predicted results are compared with the previous experimental result. Mean velocity profile at the center of gap region are compared with experiments for its validation. Spectral analysis on the lateral velocity in the center of the gap is presented. Auto and cross correlation for the axial-flow velocity pattern are presented. The unsteady structure of the flow pulsation was visualized in the region of the gap in the parallel channel.