원심식 박막증발기를 이용해 마늘착즙을 증발 농축하면서 급액속도가 증발표면에서의 액의 흐름상태와 운전 특성에 미치는 영향에 대해서 조사하였다. 급액속도 $25{sim}125kg/h$의 운전 조건하에서 증발표면에서의 이론적인 박막의 두께는 $0.52{sim}0.89mm$ 그리고 체류시간은 $1.77{sim}6.75$초로 계산되었다. 한편 Reynolds number로 판단해 볼 때 증발표면에서의 마늘착즙의 흐름은 대체로 층류로 여겨졌다. 일정한 증기 및 증발온도 조건하에서 농축비는 급액속도가 증가함에 따라 감소한 반면 증발속도와 총괄열전달계수는 어느 일정한 값까지 증가하다가 감소하는 경향을 나타내었다. 그리고 급액속도 $25{sim}125kg/h$(증발온도 $40^{circ}C$, 증기온도 $95{sim}120^{circ}C$, 급액의 초기농도 $32^{circ}Brix$)에서 농축비는 $1.04{sim}2.04$, 총괄열전달계수는 $3,074.33{sim}17,614.70kJ/m^{2}{cdot}h{cdot}^{circ}C$ 였다.
During the evaporation of garlic juice by centrifugal thin film evaporator (Centri-Therm, CT-1B), the effect of feeding rate was investigated for its operation properties. On the process condition of feeding rate of 25 to 125 kg/h, theoretical average thickness of the garlic juice film on the rotating cone and residence time of the juice in the evaporator varied in the range of 0.52 to 0.89 mm and 1.77 to 6.75 second, respectively. And the flow of garlic juice was considered as a streamline flow by Reynolds number. At constant temperatures of steam and juice evaporation, concentration ratio decreased with the increase of the feeding rate. But the evapoartion rate and overall heat transfer coefficient increased with the increase of the feeding rate until the feeding rate reached a certain value and then decreased. On the conditions of $25{leq}$feeding rate ${leq}125;kg/h$, evaporation temperature of $40^{circ}C$, $95{leq}steam$ $temperature≤120^{circ}C$ and initial feed concentration of $32^{circ}Brix$, concentration ratio and overall heat transfer coefficient were $1.04{sim}2.04;and;3,074.33{sim}17,614.70kJ/m^{2}{cdot}h{cdot}^{circ}C$.
