2次元 Wall attaching jet와 plane well jet 流動의 亂流特性에 관한 연구 : 2차원 Wall attaching jet와 plane well jet 유동의 난류특성에 관한 연구

윤순현 釜山大學校 工科大學 1989 工科大學 硏究 報告 Vol.37 No.-

2次元 channel 속으로 噴射되는 2次元 噴流 : 2차원 channel 속으로 분사되는 2차원 분류

윤순현 釜山大學校 工科大學 1984 工科大學 硏究 報告 Vol.28 No.-

접선식 배치로내의 선회유동장에 관한 실험적 연구

윤순현,김경천,김대성 대한기계학회 1995 대한기계학회논문집 Vol.19 No.11

The characteristics of the flow field in the tangentially fired furnace are presented. Experiments are conducted in the simplified cold type isothermal flow model. In the measurement of flow field, a hot wire anemometer is used. The hot wire was calibrated by lookup table method. The mean velocity field and turbulence characteristics are showed with changing the nozzle angle. In the center of the model, the low speed, unstable flow region is formed. The size and position of these regions are varied with changing the nozzle angle. It can be used as fundamental data in the design of the large furnace. From the experimental results, various turbulent characteristics of swirling flow field is obtained. And the entrainment mechanism of the jet flow field is described from the distribution of the skewness and the flatness. It can be used the raw data of approximate calculation and turbulent modelling.

터빈 블레이드 형상 곡면에서의 막냉각 효율 특성

윤순현,류원택,김동건,김대성,김귀순,Yun, Sun-Hyeon,Ryu, Won-Taek,Kim, Dong-Geon,Kim, Dae-Seong,Kim, Gwi-Sun 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.3

The effects of hole expansion angle and the arrangement of nozzles on a film cooling system for a turbine-blade-shaped surface were experimentally investigated. Liquid crystal with flue-temperature correlation and an image processing system were employed to evaluate surface temperature. Distributions of cooling effectiveness were then presented to figure out the change of heat transfer characteristics with different geometric conditions of cooling-holes. It was found thats the averaged cooling efficiency on the suction surface was maximum with 10 degree of the cooling hole expansion angle. It was also shown that the averaged cooling efficiency on the pressure surface and the averaged cooling efficiency for dual array case were not affected by the hole expansion angle.

Study of Several Design Parameters on Multi-blade Vertical Axis Wind Turbine

윤순현,임희창,김동근 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

This paper describes the experimental resultsof a multi-blade vertical axis wind turbine. A vertical axis wind turbine (VAWT) of a diameter of 205 mm with multiple blades is installed in an open-type small-scale wind tunnel with the aim to study the variation of several wind design parameters (i.e., length and angle) the system. This VAWT was tested at various wind speeds of 5 to 30 m/s in steps of 5 m/s. The results show that the efficiency of this system increases with increasing wind velocities up to approximately 25 m/s,after which the efficiency drops rapidly. Moreover, because the system was found to be dependent on various parameters, skew-normal distribution was applied to predict the rotational speed as a function of several design parameters. The use of an equation for predicting the blade tip speed is discussed in this paper. Parametric surveys of the wind blade design are underway to fully understand the aerodynamic characteristics of the VAWT depending on the number, angle of attack, and chord length (W) of the blades.Regarding the efficiency, the performance depends highly on the blade angle and it has a maximum value at 45o, but when the blade angle is set to on 45o, the case of W/R = 0.39 has the highest, around a factor of 7 higher λ comparing with other cases. Regarding the effect of the oncoming wind speed, the ë ratio against the number of blades showed a typical tendency of an increase, a peak in the middle,and a gradual decrease.

단이 진 경사벽면에 부착되는 2차원 평면제트의 열전달 효과에 관한 연구

윤순현,이대희,심재경,송흥복,Yun, Sun-Hyeon,Lee, Dae-Hui,Sim, Jae-Gyeong,Song, Heung-Bok 대한기계학회 1997 大韓機械學會論文集B Vol.21 No.10

Experiments have been conducted to determine the flow and heat transfer characteristics for a two-dimensional turbulent wall attaching offset jet at different oblique angles to a flat surface. The distributions of the wall static pressure coefficient and time-averaged reattachment position for various offset ratios and oblique angles have been measured. The local Nusselt number distributions on the plate surface were also measured using liquid crystal as a temperature indicator. The new hue-capturing technique utilizing a true color image processing system was used to accurately determine the temperature of the liquid crystal. The experiments were carried out at Reynolds number, Re (based on D) of from 7300 to 21,300 with offset ratio, H/D from 2.5 to 10, and oblique angle, .alpha. from 0 deg. to 400 deg..

사각주 후류가 선형터빈익렬의 유동 및 열전달에 미치는 영향에 관한 연구

윤순현,심재경,우창수,이대희,Yoon, Soon Hyun,Sim, Jae Kyung,Woo, Chang Soo,Lee, Dae Hee 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.7

An experimental study Is conducted in a four-vane linear cascade in order to examine the influence of the wake behind rectangular bars on the flow and heat transfer characteristics. Flow and heat transfer measurements are made for the inlet Reynolds number of 66000(based on chord length and free-stream velocity). Turbulent intensity and stress are measured using a hot-wire anemometer, and to measure the convective heat transfer coefficients on the blade surface liquid crystal/gold film Intrex technique is used. Each of experimental cases is characterized by the unsteadiness measured at the entrance of the cascade. The wake behind the rectangular bars enhances the turbulent motion of the flow in the cascade passage. It also promotes the boundary layer development and transition. The results show that heat transfer coefficients on the blade surface increase with increasing unsteadiness.

2차원 채널 충돌제트에서 난류강도의 변화에 대한 유동 및 열전달 특성

윤순현,김동건,김문경,Yoon, Soon Hyun,Kim, Dong Keon,Kim, Moon KyounK 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.6

Experiments were conducted to investigate the effect of the initial turbulent intensity on the flow and heat transfer characteristics for a two-dimensional impinging jet. A square rod was installed at the nozzle exit to increase initial turbulent intensity. A hot wire probe and thermochromic liquid crystal technique were used to measure the turbulent intensity and the surface temperature. All measurements were made over a range of nozzle-to-plate distance from 1 to 10 at Re=20,000. When the rod is not installed, the maximum stagnation point Nusselt number is occurred at H/B=9. A higher initial turbulent intensity enhanced the heat transfer on the surface. A correlation between stagnation point Nusselt number and turbulent intensity are presented.

비정상 후류가 선형터빈익렬의 유동 및 열전달에 미치는 영향에 관한 연구

윤순현,심재경,김동건 대한기계학회 2001 大韓機械學會論文集B Vol.25 No.2

2차원 난류 벽부착제트의 대류열전달 특성

윤순현,이대희,송흥복,김대성,Yun, Sun-Hyeon,Lee, Dae-Hui,Song, Heung-Bok,Kim, Dae-Seong 대한기계학회 1996 大韓機械學會論文集B Vol.20 No.10

An experimental study on the convective heat transfer characteristics was performed for a two-dimensional wall attaching offset jet(WAOJ). Thermochromic liquid crystal was used to measure the plate wall temperature. The Nusselt number was measured for Reynolds numbers from 6, 500 to 39, 000, and the offset ratios from 0.5 to 15. The maximum Nusselt number point coincides with the time-averaged reattachment point and Nusselt number decreases monotonically after the jet reattaches on the wall. In the recirculation region Nusselt number minimize near the upstream corner and then increases as X/D decreases to vanishes. This suggests the existence of secondary vortices, causing an additional mixing of the flow in the corner. The correlations between the local Nusselt number and Reynolds number, Re, offset ratio, H/D, and streamwise distance, X/D are presented.