초음속 축소-확대 노즐 수치해석 및 충돌판 충돌형 젯트 밀의 분쇄 특성

길준호; 하백현

HWAHAK KONGHAK, Vol.36, No.4, 594-600, August, 1998

A Numerical Analysis of the Supersonic Convergent-Divergent Nozzle and the Grinding Characteristics of a Target-type Jet Mill

길준호, 하백현

초록

본 연구에서는 전산유체역학 CODE인 FLUENT^TM을 이용하여 여러 가지 형상의 초음속 축소-확대 노즐에 대한 기-고 혼합체의 속도분포 수치해석을 다루었고, 충돌판 충돌형 젯트 밀의 분쇄특성을 연구하였다. 수치해석 결과와 실험결과가 잘 일치하는 것을 알 수 있었고, 분쇄효율 관점에서 최적 노즐 형상을 선정할 수 있었다. 그리고 다음 인자들의 관점에서 최적 분쇄 조건을 조사하였다 : 분쇄 압력, 노즐출구에서 충돌판까지의 거리, 젯트기류 방향과의 충돌판 각도, 중량 혼합비. 그 결과 충돌거리는 노즐 출구 직경의 2-3배 거리, 충돌판 각도는 60-90。, 중량 혼합비는 0.5보다 작은 범위가 최적인 것을 발견할 수 있었다.

In this study, we dealt with numerical analysis of the velocity distribution in the flow of gas-solid mixture about the various shapes of supersonic convergent-divergent nozzle by using the computational fluid dynamics CODE, FLUENT^TM. We also studied grinding characteristics of a target-type jet mill. It was found that the results of the present numerical analysis and experiment were in good agreement. We could select the optimum nozzle shape with respect to the grinding efficiency. And then the optimum grinding conditions were investigated with respect to the following parameters : the grinding pressure, the distance from the nozzle outlet to the target plate, the angle between the jet flow direction and target surface, and the mixing ratio by weight. The results show that the optimum conditions of the collision length, target angle, and mixing ratio are 2-3 times the distance of the nozzle outlet diameter, 60-90。, and < 0.5, respectively.

Keywords:Supersonic Nozzle;Numerical Analysis;Target-Type Jet Mill;Grinding Characteristics

[References]

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[1] Okuda S, Choi WS, J. Chem. Eng. Jpn., 13, 219 (1980)

[2] Kanda Y, Honma T, Powder Sci. Eng. Jpn., 19, 70 (1987)

[3] Kanda Y, Honma T, Chem. Ing. Tech., 31, 323 (1959)

[4] Kanda Y, Honma T, Chem. Ing. Tech., 32, 129 (1960)

[5] Rumpf H, Chem. Ing. Tech., 38, 335 (1966)

[6] Rumpf H, Chem. Ing. Tech., 32, 129 (1960)

[7] Rumpf H, Chem. Ing. Tech., 32, 335 (1960)

[8] Schlaug H, "Dechema Zerkleininern Symposium," Verlag Chemie, Weinheim, und VDI-verlag, Dusseldrof, p. 531 (1963)

[9] Okuda S, Choi WS, J. Chem. Eng. Jpn., 11, 432 (1978)

[10] Okuda S, Choi WS, J. Chem. Eng. Jpn., 12, 383 (1979)

[11] Viswanathan K, Bulk Solid Handling, 7, 585 (1987)

[12] Inoue T, J. Soc. Powder Technol. Jpn., 22, 404 (1985)

[13] Bull FA, J. Inst. Fuel, 28, 163 (1955)

[14] Tanka T, Ind. Eng. Chem. Process Des. Dev., 12, 213 (1973)

[15] Beke B, "Principle of Comminution," Publishing House of the Hungarian Academy of Science, Budapest, p. 27 (1964)

[16] Honma T, Bull. Yamagata Univ., 18, 79 (1985)

[17] Morisi SA, Alexander A, J. Fluid Mech., 55, 193 (1972)