Cyclone의 捕集效率과 壓力損失에 관한 硏究(第二報)

鄭炅樂,卞潤燮,金成鍾,張京桓 전북대학교 공업기술연구소 1986 工學硏究 Vol.17 No.-

The efficiencies of dust collection and the pressure drops of cyclones were examined concerning the tangential type cyclones under various experimental condi-tions; 1) changing the throat diameter of the cyclone. 2) changing the height and dimeter of the dust bunker. 3) changing the mean inlet velocity of cyclones. As shown in fig. 4 to 13, the experimental results can be summarized as follows; 1. When the inlet gas velocity is increased, the pressure drop is kept to regularity comparatively for each the throat diameter of the cyclone, and at 20m/sec over, it is tend to increase rapidly. 2. The influence of pressure drops according to the throat diameter of cyclone is not significant, but if the throat diameter is smaller than the diameter of gas outlet, the difference of pressure drops is about 100,, H_2O, and if the throat diameter is larger than that, it is about 40mmH_2O. 3. The influence of the dust bunker dimemsions on pressure drop is no significant. However when the throat diameter is larger, a large dust bunkers are better than a small dust bunkers. 4. When the inlet velocity is increased, the collection efficiency is unlter com-paratively, but at 20m/sec over, it tends to decrease. 5. When the throat diameter of cyclone is smaller than the gas outlet orifice, the collection efficiency is kept to unity comparatively with respect to the inlet velocity, but the throat diameter is larger than that, the collection efficiency tends to decrease over 10% ^. The influence of dust bunker dimemsions is not significant with respect to the collection efficiency dust bunker dimemsion, but when the throat diame-ter of cyclone is larger than the gas outlet orifice, the collection effic-iency tends to increase slightly.

유비무환

정경락 한국화학공학회 1995 NICE Vol.13 No.1

TiO_2 超微粒子의 熱的 擧動에 관한 연구

정경락,변윤섭,김성종,장경환,양영석,정인수 전북대학교 공업기술연구소 1991 工學硏究 Vol.22 No.-

Anatase TiO_2 particles prepared by experiment were used to study change of crystal structure by calcination temperature. The results were as follows. Crystallite size of anatase TiO_2 particles increased with calcination temperature. The rate of increasing the crystallite size of anatas TiO_2 particles was decreased below 700℃ and was markedly increased above 700℃. Unit cell volume of TiO_2 was expanded at low temperature and was contracted at high temperature. This result means that the growth of crystallite size was occurred in the C direction.

Hopper에 있어서 粉粒體의 流動에 關한 硏究

鄭炅樂 전북대학교 공업기술연구소 1976 工學硏究 Vol.5 No.-

These studies were intented to give basic informations on the Gravitational Flow of Granular Materials from a Hopper. Results are summarized as follows; If we could sum up many studies on the Gravitational Flow of Granular Materials from a Hopper two fields, those have to be the Gravitational Flow Mechanism and the Gravitational Flow Rate. Even if we take a little account of Size Distribution and Cohesive Force of Granular Materials, we are found to obtain the materials for a proper design from previous Empirical Equations, when General Equation required to calculate the Flow Rate Equation of Granular Materials from a Hopper is not discovered.

제 12 회 분체공학 하계 워크샵을 마치고

정경락 한국화학공학회 1998 NICE Vol.16 No.5

Cyclone의 捕集效率에 關하여 第一報

鄭炅樂 全北大學校 1969 論文集 Vol.11 No.-

Dust Collection efficiencies of cyclones were examined with the various types of cyclones at various experimental conditions-changing the angles, such as 15°, 30°and 60°of the conical part keeping the constant effect height of cyclone-(L+hc)=const. It was found as the following; (1) The smaller angle of conical part shows the higher collection efficiency of cyclone. (2) The efficiency of the volute type is generally higher thant hat of the tangential type. (3) Less then 15°, the volute type and the tangential type would show the same results in the collection efficiency. (4) The equationsn(1/σ_c)↑, 1/σ_cαZ, Z=(￠rd/d) √(ViH/a) are valid.

섬유상활성탄에 의한 수용액중 페놀류의 흡착특성

정경락,장경환 全北大學校 1992 論文集 Vol.34 No.-

The adsorption characteristics of phenols by the surface-modified activated carbon fibers from its aqueous solution was examined. Cellulose activated carbon fiber(toyobo Co. KF-1500) was used as an adsorbent, and it was treated with heat, air and helium. Pore-size distribution, BET surface area and surfce acidity were measured. The adsorption isotherms were found to conform with the Freundlich equation and its k values were ranged from 1.5381 to 3.6076 mmol/ g and its 1/ n values were ranged from 0.1798 to 0.3144. The affinity of each adsorbate on activated carbon fiber increased in the order ; Phenol <PCP<PNP. The adsorption capacity decreased when oxidized carbon was used, while it increased when redused carbon was used. The adsorption capacity increased when its surface area increased. It is concluded that the adsorption capacity changes in relation with the surface oxides and the surface area of the activated carbon fiber.

氣相反應에 依한 酸化物 超微粒子의 製造

鄭炅樂,金成種,張京桓,卞潤燮,梁榮錫,鄭寅洙 전북대학교 공업기술연구소 1990 工學硏究 Vol.21 No.-

The production of TiO_2 ultrafine particles from TiCl_4 and oxygen by the vapor phase reaction was investigated at 850~1000℃, whith an emphasis on the effects of its operation on the particle size distribution of the products. The results were as follows: 1) The average particle size of TiO_2 was 0.191~0.213μm and its particles were single crystals. 2) The average particle size did smaller with the increasing of reaction temperature. 3) The average particle size of TiO_2 did smaller with the increasing in the oxygen concentration and decreasing in the TiCl_4 concentration. 4) The weight fraction of rutile in the TiO_2 particles gradually increased to 900℃ and increased largely at 1000℃. The weight fraction of rutile in TiO_2 particles attached the reaction tube wall increased rapidly because of the effects of heat treatment. 5) The weight fraction of rutile in the TiO_2 particles decreased with the increasing of the oxygen and TiCL_4 concentration.

化學技術情報에 대한 定期刊行物의 素引作業에 關한 硏究

鄭炅樂 全北大學校 1976 論文集 Vol.18 No.-

The uniterm card system and the termatrex card system, both based on the principle of coordinats indexing, have been analyed as specified below, along with the analysis of thesaurus as a term control descriptor. (1) The uniterm card system: merits: a. easy to use even without technical knowledge. b. inexpensive c. possible to store much information with few cards. d. mechanizable by the method of concept coordination. e. convenient as a means of storing and retrieving documents concerning single subjects. demerits: a. its user should have sufficient knowledge about the subject matters concerned to arrange various relations among uniterms and to modify word order and meanings. b. the system is complex and requires time and efforts in analyzing subject matter. c. it is difficult to store much information in smallsized cards. d. the retrieval process in complicated. (2) The termatrex card system: merits: a. the retrieval process is simple. b. information can be retrieved with little expense. c. it is easy to use. d. information retrieval takes little time. e. it is possible to select or add any indexing terms. demerits: a. the amount of information storage is limited to 100,000 items, due to the design of cards. b. The installation of input machines costs much. c. Input processes require much efforts. d. Materials cannot be retrieved directly: only their code numbers are retrieved. e. it is difficult to revise information file. f. the functions of storage and retrieval are not interrelated. (3) These systems are applicable to: a. retrieval of pattern information. b. management of research reports. c. management of (architectrual) desingns. d. management of medical research material. e. personnel management. f. management of properties and lands. g. management of information on chemical products. h. development of ready-made articles. (4) In thesaurus, the meaning, hierarchy, and connotation of terms are well specified and controlled, so the thesaurus can be valuable for the classification, storage, retrieval, and distribution of information. On the other hand, the descrpitor should be used only by those who sufficiently know how to use it, because it is too restricted to accommodate natural language. Since the uniterm card system and termatrex card system are simple, inexpensive, and practical methods of information storage and retrieval, they can be usefully adopted as means of pre-computer analysis of technical and scientific information.

Tube Bank에 있어서 流線의 有無에 따른 壓力降下에 관한 硏究

정경락,정재성,김성종,김능배 전북대학교 공업기술연구소 1986 工學硏究 Vol.17 No.-

Pressure drops have been measured in 80℃ water flowing through two banks of 2.54cm steel tubes. The flow was horizontal and perpendicular to the vertical tube. The tube banks had uniform and non-uniform transverse spacing. The uniform bank was an in-line array, five tubes wide and twenty-one tubes long with 9.525mm clearance between adjacent tubes. In the nonuniform case, a tributary was formed by removing the center row of tubes. Measurements were made with and without progressive removal of water through a grid of uniform openings in the bottom tube sheet.