喷嘴直径对脉动式气体射流冲击干燥的影响

Effects of Nozzles Diameter on Pulsed Air-impingement Drying

喷嘴直径是影响气流喷射传热的主要因素之一,为揭示喷嘴直径对脉动式气体射流冲击干燥的影响规律,本文选用5种不同直径的喷嘴对加工番茄进行了干燥实验,结果表明:干燥初期喷嘴直径对干燥速率影响较大,且在实验范围内干燥速率随喷嘴直径增大先增大后减小,当喷嘴直径为18 mm时,干燥速率最大;当加工番茄干燥至终了含水率为11%(湿基)时,所需要的干燥时间随喷嘴直径的增大先缩短后延长,当喷嘴直径为18 mm时,干燥时间最短,约为14 h。因此,在实验条件下选用直径为18 mm的喷嘴可提高干燥速率和缩短干燥用时,这可为脉动式气体射流冲击干燥机喷嘴直径的选择提供参考。

Nozzle diameter is one of the main factors affecting drying,To reveal the influence law of nozzle diameter to pulsed air- impingement drying,the drying experiments were conducted under five different nozzle diameters.The result showed that nozzle diameter had great impact on drying rate during the initial period,the drying rate firstly increased,then decreased with the increase of nozzle diameters.The drying rate was largest and the drying time was shortest with 14 hours when the nozzle diameter was 18 mm.The time of drying to water content of 11% was firstly contracted and then expanded with the increase of nozzle diameters.So,selected the nozzle of 18 mm diameter could improve the drying rate,shorten the drying time under the experimental conditions.The results could provide references for selecting the appropriate nozzle diameter of pulsed air- impingement dryer.