风机顶置和直对式隧道干燥机对比试验研究

Comparative study on direct/bypass blowing of tunnel dryers

人们普遍使用传统隧道式干燥机生产脱水菜。它的热风机在顶部或侧面。研究表明 ,风机顶置式隧道干燥机的风速分布很不均匀 ,并且在干燥室的上部有两个相对风速很小的区域 ,导致干燥不均匀和霉变发生。该文采用风机放置在 (干燥室 )前面的结构形式 ,使空气流动均匀。干燥胡萝卜粒的结果表明 ,含水率由原来的 11%～ 2 0 %变为 11%～ 13 %。脱每千克水降低能耗 2 .2 5 MJ。干燥时间缩短 13 %。但是占地面积要比风机顶置式大 19%。

The most common way to make dehydrated vegetables in China now is tunnel drying. In this process, the hot air blower is set on top of or beside the tunnel. A study on the hot air flow pattern (blower positioned on top) indicated that the wind speed distribution was uneven and there were two relatively static air zones on the top of the inside of the tunnel, resulting in uneven drying and in extreme mildewing. Authors of this paper developed a new structure in which the blower is set in front of the tunnel to improve air flow pattern. Results of drying carrot granules showed: a) moisture contents of the granule were more even (11%～13%) than that of the bypass model (11%～20%); b) 2.25 MJ energy consumption was reduced for 1 kg of water dehydrated; c) drying time was shortened by 13%. However, the new structure takes up 19% more land than that of positioning the blower on the top of the tunnel.