공기 분배기로부터 0.2m 높이에 2차 공기가 공급되는 상온 유동층(직경 0.1m, 높이 2.4m)에서 입자 비산속도를 측정 및 고찰하였다. 층물질로는 체규격 0.5mm 이하의 모래가 사용되었다. 실험변수로는 입도(0.128-0.363mm), 총괄유곡(0.76-2.77m/s), 2차 공기분율(0-0.5), 고정층 높이(0.1-0.3m)가 변화되었다. 입자 비산속도는 유속이 증가할수록 입경이 감소할수록 증가하였다. 고정층 높이의 영향은 미약하였다. 2차 공기분율의 증가는 입자 비산속도를 감소시켰다. 이 영향은 2차 공기의 주입위치에 따라 다르며, 층내부일 경우에는 작으나, 프리보드일 경우에는 두드러졌다.
The particle entrainment rate was measured and discussed in a cold model fluidized bed(0.1m-ID, 2.4m-height) which employed a secondary air injection at a height of 0.2m above the distributor plate. Sand particles of mixed sizes under 0.5mm in screen size were used as bed materials. The particle size(0.128-0.363mm), the overall superficial gas velocity(0.76-2.77m/s), the secondary air fraction(0-0.5), and the static bed height(0.1-0.3m) were considered as experimental variables. The entrainment rate increased with the gas velocity, but with a decrease of particle size. The effect of static bed height was negligible. The entrainment rate decreased with an increase of the proportion of secondary air. The effect of secondary air fraction was appreciable for over-bed injection and was reduced as the location of second gas inlet moved toward in-bed.
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