急擴大管內에서 亂流旋回流動의 熱傳達에 관한 硏究

권기린(Ki-Rin. Kwon),허종철(Jong-Chul Huh) 한국해양공학회 1996 韓國海洋工學會誌 Vol.10 No.3

Many studies of heat transfer on the swirling flow or unswirled flow in a abrupt pipe expansion are widely carried out. The mechanism is not fully found evidently due to the instabilities of flow in a sudden change of the shape and appearance of turbulent shear layers in a recirculation region and secondary vortex near the corner.<br/> The purpose of this study is to obtain data through an experimental study of the swirling flow and heat transfer downstream of an abrupt expansion in a circular pipe with uniform heat flux.<br/> Experiments were carried out for the turbulent flow and heat transfer downstream of an abrupt circular pipe expansion. The uniform heat flux condition was imposed to the downstream of the abrupt expansion by using an electrically heated pipe. Experimental data are presented for local heat transfer rates and local axial velocities in the tube downstream of an abrupt 3:1 & 2:1 expansion.<br/> Air was used as the working fluid. In the upstream tube, the Reynolds number was varied from 60,000 to 120,000 and the swirl number range (based on the swirl chamber geometry, i.e. L/d ratio) in which the experiments were conducted were L/d=0, 8 and 16.<br/> Axial velocity increased rapidly at r/R=0.35 in the abrupt concentric expansion turbulent flow through the test tube in unswirled flow. It showed that with increasing axial distance the highest axial velocities move toward the tube wall in the case of the swirling flow abrupt expansion.<br/> A uniform wall heat flux boundary condition was employed, which resulted in wall-to-bulk temperatures ranging from 24℃ to 71℃. In swirling flow, the wall temperature showed a greater increase at L/d=16 than any other L/d. The bulk temperature showed a minimum value at the pipe inlet, it also exhibited a linear increase with axial distance along the pipe.<br/> As swirl intensity increased, the location of peak Nu numbers was observed to shift from 4 to 1 step heights downstream of the expansion.<br/> This upstream movement of the maximum Nusselt number was accompanied by an increase in its magnitude from 2.2 to 8.8 times larger than fully developed tube flow values.

超音波에너지가 附加된 混合燃料를 이용한 機關의 性能에 관한 硏究

권기린,부영진 제주대학교 공과대학 첨단기술연구소 2002 尖端技術硏究所論文集 Vol.13 No.1

This is an experimental study on the possibility of using a blend oil by ultrasonic adding in diesel engines. It is compared to engine torque, the rate of fuel consumption, the thermal efficiency and ultrasonic adding effect for engine speed. The results are obtained as follows : 1. Of all the fuel oil, it is indicated that the maximum torque is at 2000rpm and the torque is rapidly decreased according to increasing engine speed. When engine speed is more than 2400rpm, it is found that blend oil is lower and the blend oil of ultrasonic supply is the same, in compared with the torque of light oil. 2. With the ultrasonic adding in fuel, the thermal efficiency is estimated average of 28.4% and maximum of 30.07% in light oil and average of 30.29% and maximum of 31.09% in blend oil. The result confirms that blended oil is better than light oil for the improved effect of thermal efficiency with ultrasonic adding. From the above results, in order to apply blend oil to engine fuel, it will be desirable to apply the very high added effect of ultrasonic energy, and also, thoroughly investigate the rapid drop of torque and thermal efficiency and the phenomenon that the amount of fuel consumption increases at high engine speeds.

偏心된 入口를 갖는 急擴大管에서의 난류 旋回流動과 熱傳達에 관한 硏究

권기린 濟州大學校 工科大學 産業技術硏究所 1998 尖端技術硏究所論文集 Vol.9 No.1

An experimental study of decaying swirl air flow has been obtained by tangential inlet in an abrupt expansion tube. Experiments were carried out for the turburlent swirling flow and heat transfer characteristics of an eccentric expansion in a circular tube with a constant heat flux. The uniform heat flux condition was imposed to the downstream of an eccentric expansion by using an electrically heated tube and the flow upstream of the expansion was unheated and fully developed. Experimental data are presented for local axial velocities and local heat transfer rates in the tube downstream of an abrupt 3:1 expansion. Air was used as the working fluid. In the upstream tube, the Reynolds number was varied from 60,000 to 100,000 and swirl number range(based on the swirl geometry, i.e. L/d ratio) in which the experiments were conducted was L/d = 0, 5. The results obtained are summarized as flows. 1) Fully development region showed from x/d=16 to downstream in case of non swirl flow but x/d=24 on the swirl flow. 2) A ratio of friction factors(fs/f) of the test tube inlet were increased 600∼1400% than that of value for fully developed flow. 3) The wall temperature and the bulk temperature showed high when Reynolds numbers was small and swirl intensity was incresed. 4) The location of the maximum Nu/NuDB showed at the point of 4 step hights, for Re=60,000. 5) It was found that the swirl flow behaviors depend on the swirl intensity along the test tube.

冷却水溫 變化에 따른 가솔린 기관 特性에 關한 實驗的 硏究

권기린,홍성수 제주대학교 산업기술연구소 2000 尖端技術硏究所論文集 Vol.11 No.1

The purpose of this study is to prevent the stick, scuffing, scratch between piston and cylinder in advance, to obtain data for duration test in actual engine operation. The temperature gradient in cylinder bore according to coolant temperature were measured in use of 1.5ℓ class gasoline engine. 20 thermocouples were installed at points of 2mm inside from cylinder wall near top ring of piston in cylinder block, which points have suffered major thermal loads and suggested as proper measurement points for engine design by industrial engineers. Under full load and 70℃, 80℃ and 90℃ coolant temperature conditions, the temperature in cylinder block and engine oil increased gradually in according to the increase of coolant temperature, the siamese side temperature of top dead center is 142℃ in peripheral distribution, that is about 20℃ higher than thrust, anti-thrust, and rear side temperature, the fuel consumption in 70℃ coolant temperature is lower than 80℃ and 90℃ coolant temperature, the engine torque in 80℃, 90℃ coolant temperature condition is about 0.5kg.m higher than 70℃ coolant temperature.

풍하중을 고려한 제주형 작물재배용 비닐하우스모델의 구조해석

권기린(Kwon Ki-Rin),민창식(Min Chang-Shik),김용호(Kim Young-Ho) (사)한국생물환경조절학회 1998 생물환경조절학회지 Vol.7 No.3

油菜油 燃料를 利用한 디젤耭關의 性能特性에 關한 實驗的 硏究

권기린,오영옥 제주대학교 공과대학 첨단기술연구소 2002 尖端技術硏究所論文集 Vol.13 No.1

A four cycle diesel engine performance test was performed with four kinds of oils such as rape seed oil, effective micro-organism rape seed oil, activated clay rape seed oil and light oil. The experiment was conducted at full load condition with constant injection time of the engine and the test oil temperature was maintained at 70±2℃. The torque and the horsepower with rape seed fuel is increased about 10% compare with light seed oil at full load condition of the engine. The emission of the smoke gas was decreased 29%, 38% and 52% compare with light oil in rape seed oil, effective micro-organism rape seed oil and activated clay rape seed oil respectively. Engine inspection results shows that the soot adherence amount of the cylinder head piston head is higher in following order: activated clay rape seed oil > effective micro-organism rape seed oil > rape seed oil > light oil.

Scoria, Trachyte, Styropor의 保溫 斷熱性에 關한 實驗的 硏究(Ⅱ)

權麒麟,許鐘哲 제주대학교 1986 논문집 Vol.22 No.-

In this paper, we tried to compare Scoria and Trachyte with Styropor in the effect of insulator for the purpose of the economic utilization of natural resources. The results of this study may be summarized as follows; 1. The properties of temperature variation in model rooms, (ⅰ) The temperature increases in the order of Styropor, Scoria, Trachyte. (ⅱ) The temperature decreases in the order of Trachyte, Scoria, Styropor. 2. The effects of temperature variation, (ⅰ) When the temperature increases Scoria and Styropor showed almost the same effect or variation. (ⅱ) When the temperature decreases Trachyte and Scoria showed almost the same variation or effect. 3. Temperature variations in accordance to the pass of time, (ⅰ) When the temperature rises, it increases sharply for the first 80 minutes, but gradually since then. (ⅱ) When the temperature falls, it decreases gradually for the first 60 minutes, but sharply since then.

경사진 입구를 갖는 급확대관내의 난류유동과 열전달특성에 관한 실험적연구

권기린,한진규 濟州大學校工科大學附屬産業技術硏究所 1994 尖端技術硏究所論文集 Vol.5 No.-

Experiments were carried out for the turbulent flow and heat transfer downstream of an 10˚-inclined concentric expansion in a circular pipe with a constant wall heat flux. The uniform heat flux condition was imposed to the downstream of an inclined expansion by using an electrically heated pipe and the folw upstream of the expansion was unheated and fully developed. Runs were made with small diameter to large diameter ratio of 0.33 and over the Reynolds numbers range of 60,000, 90,000 and 120,000(based on upstream diameter). Experiments were tested with air as working fluid. The results ovtained are summarized as follows ; 1) Fully development region showed from x/d=22 to downstream in an 10˚-inclined concentric expansion turbulent flow through the test tube. 2) Friction factors of the test tube showed a maximum value at x/d=15. 3) For all Reynolds number, the wall temperature showed a curve of parabolic variation at 16<x/d<48, and the bulk temperature showed a linear distribution of increase at 9<x/d<48. 4) The location of the maximum Nu/Nu?? showed at the point of 16 step-heights for Re=60,000, 90,000 and 120,000 of an 10˚-inclined concentric expansion.

경사진 입구를 갖는 급확대관내의 난류유동과 열전달특성에 관한 실험적 연구

권기린,한진규 濟州大學校 工科大學 産業技術硏究所 1994 産業技術硏究報告 Vol.5 No.-

Experiments were carried out for the turbulent flow and heat transfer downstream of an 10^(2) -inclined concentric expansion in a circular pipe with a constant wall heat flux. The uniform heat flux condition was imposed to the downstream of an inclined expansion by using an electrically heated pipe and the folw upstream of the expansion was unheated and fully developed. Runs were made with small diameter to large diameter ratio of 0.33 and over the Reynolds numbers range of 60,000, 90.000 and 120,000 (based on upstream diameter). Experiments were tested with air as working fluid. The results ovtained are summarized as follows; 1) Fully development region showed from x/d=22 to downstream in an 10^(2) - inclined concentric expansion turbulent flow through the test tube. 2) Friction factors of the test tube showed a maximum value at x/d=15. 3) For all Reynolds number, the wall temperature showed a curve of parabolic variation at 16<x/d<48, and the bulk temperature showed a linear distribution of increse at 9<x/d<48. 4) The location of the maximum Nu/NuDB showed at the point of 16 step-heights for Re= 60,000, 90,000 and 120,000 of an 10^(2) - inclined concentric expansion.

偏心된 입구를 갖는 급확대관에서의 난류 선회유동과 열전달에 관한 연구

권기린 濟州大學校 産業技術硏究所 1998 산업기술연구소논문집 Vol.9 No.1

An experimental study of decaying swirl air flow has been obtained by tangential inlet in an abrupt expansion tube. Experiments were carried out for the turburlent swirling flow and heat transfer characteristics of an eccentric expansion in a circular tube with a constant heat flux. The uniform heat flux condition was imposed to the downstream of an eccentric expansion by using an electrically heated tube and the flow upstream of the expansion was unheated and fully developed. Experimental data are presented for local axial velocities and local heat transfer rates in the tube downstream of an abrupt 3:l expansion. Air was used as the working fluid. In the upstream tube. the Reynolds number was varied from 60.000 to 100.000 and swirl number range(based on the swirl geometry, i.e. L/d ratio) in which the experiments were conducted was L/d = 0. 5. The results obtained are summarized as flows. 1) Fully development region showed from x/d=16 to downstream in case of non swirl flow but x/d=24 on the swirl flow. 2) A ratio of friction factors(fs/f) of the test tube inlet were increased 600~1400% than that of value for fully developed flow. 3) The wall temperature and the bulk temperature showed high when Reynolds numbers was small and swirl intensity was incresed. 4) The location of the maximum Nu/NuDB showed at the point of 4 step hights. for Re=60,000. 5) It was found that the swirl flow behaviors depend on the swirl intensity along the test tube.