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Heavy Steer의 Chrome Tanning에 있어서 Chrome 利用에 關한 硏究
尹福鉉,李錫健 忠南大學校 1974 論文集 Vol.13 No.1
In order to obtain optimum condition in chrome tanning systems, the temperature, pH of chrome liquor and rotation of drum were invvestigated by fixative chrome on the bath or green leather. The experimental results obtained were as fellows. 1. It was found that optimum combination of condition for chrome and carbonyl radical of collagen is when water was added 60 %. 2. In added water 60%, it was found that optimum temperature of the bath for chrome tanning is 25∼27℃. 3. When drum speeded with 15 r. p. m. physical properties of leather are optimum condition for increasing temperature of liquor. 4. As water of pelt weights was added 60%, it was found and fixative chrome of middle part are high and grain and fresh part are very similar.
A Mathematical Model for a Normal Shock Wave Structure
Yoon, Bokhyun 木浦大學校 工業技術硏究所 1998 工業技術硏究誌 Vol.8 No.-
A mathematical model for a normal shock wave structure with diffusion is presented. As for the diffusion, multicomponent mixture model rather than binary mixture model is adopted. In almost all of studies on diffusion problems. Fick's law is used. But in this study the exact law of diffusion obtained from the precise constitutive relations stemming from the kinetic theory of gases is implemented. The mathematical procedure which is quite complicated is formulated and its basic solution is also presented. The shock wave is usually considered as a kind of discontinuity. However, in this investigation, a shock wave structure model with a finite thickness is introduced and studied by means of ternary mixture diffusion model.
Ternary Mixture Diffusion Effects in Boundary-Layer Flows
Yoon, Bokhyun 木浦大學校 工業技術硏究所 1996 工業技術硏究誌 Vol.6 No.-
An evaluation of multicomponent diffusion effects in hypersonic flows is presented. Of particular interest is a comparison of the results obtained from the common simplifying assumption of Fick's law with the results obtained from the precise constitutive relations stemming from the kinetic theory of gases. To fix ideas, the flow of a ternary mixture past a flat plate is considered. for which perssure diffusion is negligible. Whereas the precise analysis is more complicated, the results for the mass-fraction distribution can be significantly different from the corresponding simpler analyses stemming from Fick's law.
노즐내 이차원 물체에 의한 피동제어된 아음속 제트구조에 관한 연구
오대근,윤복현,김태호 국립7개대학공동논문집간행위원회 2003 공업기술연구 Vol.3 No.-
A turbulent wake generated by a cylinder in nozzle contraction affects to the jet flow characteristics. In this study, a computational work to investigate the effect of the turbulent wake on two-dimensional subsonic jet was carried out with three different kinds of nozzle. Computations are applied to the two-dimensional unsteady, Navier-Stokes equations. Several kinds of turbulent models and wall functions are employed to validate the computational predictions. It was known that the wake flow enhanced the spread of the jet flow, compared with no wake flow condition. It was also found that the jet core is shortened by the wake flow developed from a control cylinder.
多點 피토관 流量計의 流量係數 測定에 관한 실험적 연구
임재명,윤복현 木浦大學校 工業技術硏究所 2000 工業技術硏究誌 Vol.10 No.-
The performance of multi-point Pitot tube flow-meter with diamond shape depending on the combination of upstream double elbows was experimentally studied. Actual flow-rates were measured by using ISA 1932 nozzles which are all standard flow-meters. Based on the measured flow-rates the flow coefficients of the multi-point flow-meter could be obtained. The flow coefficients calculated with all the front four holes open agree very well with those calculated by means of the average coefficient for the all holes. Furthermore, the flow coefficients were quite indifferent to Reynolds number variation for the region of ReD> 5.5×104. It is mostly due to the fact that the straightener installed upstream makes the flow more stable and straight than the case without the straightener ahead of the test section.
장석,윤복현 국립7개대학공동논문집간행위원회 2001 공업기술연구 Vol.1 No.-
The performance of a wet gas meter using water as a sealing liquid was tested by means of a standard gas flow measuring system operating at the room temperature in Korean Research Institute of Standards and Science (KRISS). The original data from the wet gas meter were calibrated by using the humidity measured at the meter exit. As a result, the error of the wet gas meter was decreased remarkably. This means that humidity affects the performance of the wet gas meter significantly. These data and results are expected to be used as bases for further researching and developing various wet gas meters afterwards.
장석,윤복현 국립7개대학공동논문집간행위원회 2003 공업기술연구 Vol.3 No.-
The flow characteristics of small sonic nozzles which were manufactured by ISO 9300 and effects of the shape of nozzle on the measurement of flow rate were found by using numerical analysis. The model with 4.48mm of throat diameter was used and shape of sonic nozzle entrance and flat throat nozzle was adapted as a variable to estimate the effect of the shape of nozzle on the flow rate measurement. The flow of the small sonic nozzle was similar to thar of the ideal gas isentropic and the critical pressure ratio was restored to the stagnation pressure due to the effect of the expansion part. The results showed that the discharge coefficient was smaller than ISO 9300 by 2% in case the shape of nozzle entrance was conical, on the other hand, by 3% in case the shape if nozzle throat was the flat part. However, In both of the two cases the characteristics of discharge coefficient was similar to the nozzle of ISO 9300.
실린더 후류를 이용한 아음속 디퓨저 유동의 제어에 관한 연구
오대근,윤복현,김태호 국립7개대학공동논문집간행위원회 2005 공업기술연구 Vol.5 No.-
The present study addressed a computational work to investigate the influence of a turbulent wake flow on the pressure recovery of subsonic diffuser. The turbulent wake is generated by a cylinder with a small diameter, which is installed at the diffuser inlet of a 2-dimensional diffuser Computation are applied to three-dimensional steady Navier-Stokes equations. The computational results are qualitatively well compared to existing experimental results. The results show that the diffuser pressure recovery of the subsonic diffuser is dependent on the diameter and location of the cylinder. It is found that a certain diameter and location of cylinder to generate the turbulent wake give a better pressure recovery, compared with no cylinder flow
차지선,윤복현 木浦大學校 工業技術硏究所 1999 工業技術硏究誌 Vol.9 No.-
The accuracy of gas flow measurements by using small sonic nozzles and flow characteristics of small nozzles are investigated in the gas flow standard measurement system. The experiments are performed at various nozzle throat diameter and inlet pressures. The overall uncertainty of discharge coefficients is estimated to less than ±0.2 percent at a confidence level of 95 percent. The discharge coefficients(Cd) as a function of throat Reynolds number are in agreement with the recommended equation of ISO 9300 document. The boundary layer affects the discharge coefficients, as the nozzle throat diameter is small. A correlating equation for discharge coefficients is derived.