【摘要】 研究超声场强化芋头渗透脱水,探讨芋头失水速率和干物质增加率随溶液质量浓度、温度、超声功率、材料厚度以及超声场下处理时间段的变化规律。分析超声空化泡在相间的传质过程,由此建立超声空化气泡强化相间传质数学模型Km≈DABπtm～(1/2)RδAfφ(BI-Cf2)(A为经验常数(10-8～10-15m2);B、C为超声波作用液体的有关常数,数量值分别在1014、106左右;f为声波频率/s-1;DAB为扩散系数/(m2/s);tm为时间/s;R为半径/m;δ为边界层厚度/m;φ为半径为R的气泡数占生成空化气泡总数百分比;I为声强/(W/cm2)),与实验结果相吻合,能较好地描述超声空化泡在液体中的传质行为。该关系式为超声波强化传质过程提供了理论依据。更多还原

【Abstract】 Variations in water loss and dry matter gain with respect to solution concentration,temperature,ultrasonic power,material thickness and ultrasonic time were investigated.Meanwhile,the interphase mass transfer of ultrasonic cavitation bubbles was analyzed.As a result,a mathematical model that describes the interphase mass transfer of ultrasonic cavitation bubbles was obtained as follows:Km≈ DABπtm～(1/2)RδAfφ(BI-cf2),where A was empirical constant(10-8-10-15 m2),B and C relevant liquid constants with an approximate value of 1014 and 106,respectively,f sound frequency(s-1),DAB diffusion coefficient(m2/s),tm time(s),R radius(m),δboundary layer thickness(m),φratio of number of bubbles with a radius of R to total bubbles,and I ultrasonic intensity(W/cm2).The predicted values from the model were consistent with the experimental values,indicating that the model could accurately describe the interphase mass transfer of ultrasonic cavitation bubbles.更多还原