摘要
利用变时间步长的有限体积法对具有电介质核心多孔介质微波冷冻干燥的耦合热质传递过程进行了数值模拟。计算结果表明:在有电介质核的多孔介质内部存在着两个升华界面,该双升华界面模型成功地模拟了该干燥过程;合理的选用电介质核心可以大大缩短干燥时间,对于几个大小分别为1.0,1.5,2.0和2.5mm的电介质核,其单位体积所需干燥时间同无核相比分别减少了8%,19%,33%,48%;在相同的电场强度下,电介质核的损耗系数越大,所需干燥时间越短。
Microwave freeze drying of porous media with dielectric cores was studied numerically. The sets of transient governing equations developed for the conjugate heat and mass transfer process was derived and solved with variable time-step finite volume method. Numerical results show that two sublimation fronts do exist within the porous media, and this is a new phenomenon associated with dielectric core. The two sublimation fronts model proposed can successfully simulate this drying process of porous media with dielectric cores. A dramatic drying time saving could be obtained with proper selection of dielectric cores. Comparing with that of porous media without dielectric core, the drying time per unit volume decreases by 8%, 19%, 33% and 48%, for the porous media with 1.0, 1.5, 2.0 and 2.5mm dielectric core, respectively. It is found that the drying process is mostly influenced by the core size and the loss factor of the core material. Bigger loss factor results in a shorter drying time under the same electric field strength.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2005年第2期181-186,共6页
Journal of Chemical Engineering of Chinese Universities
关键词
传热和传质
冷冻干燥
多孔介质
电介质核心
损耗系数
Electric fields
Finite volume method
Heat transfer
Mass transfer
Mathematical models
Numerical methods
Porous materials
