壳聚糖溶液水力空化泡动力学的数值模拟

Numerical Simulation of Hydrodynamic Cavitation Bubble Dynamics in Chitosan Solution

摘要:

本文基于Gilmore空泡动力学模型，采用四阶Rung-Kutta法，对孔板空化器中壳聚糖溶液水力空化泡的动力学特性进行了数值模拟。考察了壳聚糖溶液浓度、溶液温度、孔板下游管道直径、孔板喉部直径、孔板入口压力、出口压力及空化泡初始半径对壳聚糖溶液中空化泡运动的影响。模拟结果显示，对单个空泡而言，壳聚糖溶液浓度越高，空化产生的空化效应强度越弱，当浓度达到1%时，Rmax/R0只有8；溶液的温度越高，空化的强度越大，当温度达到60 ℃时，Rmax/R0达到215；孔板下游管道直径越长，产生空化效应越强，当下游管道直径为100 mm时，Rmax/R0达到335；孔板喉部直径越小，空化效应越显著，当喉部直径为2 mm时，Rmax/R0为290；孔板压力范围为0.1~0.5 MPa之间，入口压力高，出口压力越低，空化效应越好；初始半径较小的空化泡对空化作用的贡献更大，当初始半径为5 μm时，Rmax/R0为275。

Abstract:

Based on equation of Gilmore, the dynamics of cavitation bubble in chitosan solution was investigated with the cavitation reactor of orifice. By numerical simulation the effect of solution concentration, solution temperature, pipeline diameter of downstream, gular diameter, inlet pressure, outlet pressure and initial bubble radius on the motion of cavitation bubble were discussed. The results showed that with the increase of concentration, the amplitude of cavitation bubble decreased, and Rmax/R0 was only 8 when the concentration was 1%. The amplitude of cavitation bubble increased when increasing of temperature and pipeline diameter of downstream, Rmax/R0 reached 215 at 60 ℃ and 335 with 100 mm pipeline diameter, respectively. Moreover, with the decreasing of gular diameter, the amplitude of cavitation bubble increased，while the gular diameter was 2 mm, and Rmax/R0 was 290. It was found that with higher inlet pressure and lower outlet pressure the amplitude of cavitation bubble increased. The investigation also indicated that smaller initial bubble radius improved the effect of cavitation in chitosan solution, and Rmax/R0 was 275 with radius of 5 μm.