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기체유동층의 스플래쉬 영역에서 축방향 고체체류량 분포의 감쇄상수에 대한 온도의 영향
Effect of Temperature on the Decay Constant of the Axial Solid Holdup Profile in the Splash Region of a Gas Fluidized Bed
HWAHAK KONGHAK, April 1997, 35(2), 300-306(7), NONE
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Abstract
직경 0.1m, 높이 2.1m의 전기가열방식의 유동층에서 층물질로 모래를 사용하여 온도(24-600℃) 및 기체유속(0.5-2.0m/s)의 변화에 따른 전이영역에서 촉방향 고체체류량 분포의 감쇄상수를 측정하였다. 전이영역에서 고체체류량 분포의 감쇄상수는 유속이 증가함에 따라 감소하였고, 유속의 영향은 온도가 증가할수록 완만해지는 경향을 보였다. 일정유속에서 감쇄상수는 온도가 증가함에 따라 증가하였으며, 온도의 영향은 유속이 증가함에 따라 증가하였다. 본 연구의 결과와 타연구자들의 결과를 사용하여 감쇄상수에 대한 온도의 영향이 고려된 다음의 상관식을 제시하였다.
adp=exp(-11.2+210dp/(Dt-dp))(dpρg(U-Umf)/μ)-0.492[ρpgdp/ρg(U-Umf)2]0.725((ρp-ρg)/ρg)0.731CD-1.47
adp=exp(-11.2+210dp/(Dt-dp))(dpρg(U-Umf)/μ)-0.492[ρpgdp/ρg(U-Umf)2]0.725((ρp-ρg)/ρg)0.731CD-1.47
Effects of temperature(24-600℃) and gas velocity(0.5-2.0m/s) on the decay constant of axial solid holdup profile of the splash region have been measured in a gas fluidized bed(0.1m-i.d., 2.1m height) equipped with an electric heater. Sand was used as a bed material. The decay constant of axial solid holdup profile in the splash region decreased with an increase of the gas velocity. As the temperature increased, the effect of the temperature on the decay constant increased as the gas velocity increased. Based on results of this study and previous studies, a correlation on the decay constant that considers the effect of temperature was proposed as follows :
adp=exp(-11.2+210dp/(Dt-dp))(dpρg(U-Umf)/μ)-0.492[ρpgdp/ρg(U-Umf)2]0.725((ρp-ρg)/ρg)0.731CD-1.47
adp=exp(-11.2+210dp/(Dt-dp))(dpρg(U-Umf)/μ)-0.492[ρpgdp/ρg(U-Umf)2]0.725((ρp-ρg)/ρg)0.731CD-1.47
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Werther J, Hartge EU, Kruse M, Powder Technol., 70, 293 (1992)
