高频加热对落叶松含髓心方材水分迁移的影响

The Effect of Radio-frequent Heating on Water Migration for Boxed-heart Larch Lumber

以横截面120 mm落叶松含髓心方材为研究对象,检测并对比分析了高频-对流干燥与常规对流干燥过程中,试材含水率及其沿厚度方向分布的变化,探讨了高频-对流干燥过程中高频复合加热对木材内部水分迁移的影响。结果表明:1干燥过程中在对流加热的同时实施高频加热,干燥速率由单独对流干燥过程中的0.153%/h提高到0.398%/h。2高频加热对水分迁移的促进作用效果,木材纤维饱和点之上随着含水率的降低而增大,纤维饱和点时最强;纤维饱和点之下随着含水率的降低而减弱。3高频加热对含水率分布均匀性的作用效果显著,但随着干燥的进行作用效果减弱。

The cross section of 120 mm boxed-heart larch lumber was investigated. The moisture content and its distribution along the thickness direction of specimens were investigated and analyzed during radio-frequency convection drying and conventional drying. The effect of radio frequency on water migration was also discussed during radio-frequency convection drying. The results show that,1 Radio-frequent heating was carried out during conventional drying,the drying rate increased from 0. 153% / h to 0. 398 % / h. 2 The promoting effect of radio-frequency on moisture migration were various at different moisture content; above fiber saturation point,it increased with decreased moisture content; under the fiber saturation point,it decreased with decreased moisture content; and it is the strongest at the fiber saturation point. 3 Radio-frequency heating had an effective influence on the uniformity of moisture content distribution,but it became weakened as drying continue.