Abstract The break-up phenomena occurring in a high pressure homogenizer equipped with an interchangeable orifice valve were investigated by measuring the inactivation of Lactococcus lactis. Data were collected at varying the orifice size (80, 100, and 150 μm), the operating pressure (100–200 MPa), the number of passes (1–10), and the fluid viscosity (2.5–7.9 mPa s, changed by adding 0–50 % wt PEG 200 to buffered peptone water) to identify the correlations of the fragmentation occurring in the valve with the main fluid dynamic phenomena (turbulence, elongational and shear stresses, and cavitation). In addition, also the effects of a purely shearing or ultrasound treatment on cell break-up were considered. The results show that the most intense break-up phenomena occur for the smallest orifice size, highest pressure, and lowest viscosity. However, at low viscosity, turbulence, together with the elongational stresses appear to be the controlling factors of cell break-up, whereas, at higher viscosities, the shear stresses become increasingly important. The occurrence of cavitation is only slightly affected by viscosity, and mainly depends on the velocities reached in the homogenization valve.

中文翻译：

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了解使用球形细菌细胞（乳酸乳球菌）作为模型破坏指标的孔阀高压均质机中的破裂现象

摘要 通过测量乳酸乳球菌的失活，研究了配备可互换孔板阀的高压均质机中发生的破碎现象。在不同的孔口尺寸（80、100 和 150 μm）、工作压力（100-200 MPa）、通过次数（1-10）和流体粘度（2.5-7.9 mPa s，改变通过将 0-50% wt PEG 200 添加到缓冲蛋白胨水中）来确定阀门中发生的碎裂与主要流体动力学现象（湍流、伸长和剪切应力以及空化）的相关性。此外，还考虑了纯剪切或超声处理对细胞破碎的影响。结果表明，最强烈的破裂现象发生在最小的孔口尺寸、最高的压力和最低的粘度。然而，在低粘度下，湍流和拉伸应力似乎是细胞破裂的控制因素，而在高粘度下，剪切应力变得越来越重要。气蚀的发生仅受粘度影响很小，主要取决于均化阀中达到的速度。