Fluid dynamic gauging for measuring the strength of soft deposits
Fluid dynamic gauging for measuring the strength of soft deposits
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DOI：
10.1016/j.jfoodeng.2004.01.013
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发表时间：
2004-11-01
影响因子：
5.5
通讯作者：
Wilson, DI
中科院分区：
文献类型：
--
作者：
Chew, JYM;Paterson, WR;Wilson, DI
流体动态测量（FDG）是一种原位实时测量浸入液体环境中的固体表面软沉积层厚度的技术。该技术已通过层流测量流的计算流体动力学 (CFD) 模拟进行扩展，以量化施加在被测量材料上的应力。 CFD 结果通过与 (i) 静压头、(ii) 喷嘴流量系数和 (iii) 作用在测量表面上的法向应力的实验值进行比较来验证。随后使用剪切应力分布预测来确定软质食品沉积物的剪切屈服强度。将不锈钢盘上的番茄酱层（约2毫米厚）通过100摄氏度的烘箱干燥进行老化，并研究去除特性。剪切屈服强度随着干燥时间的增加而增加，直至 3.0 小时，之后强度 (13 Pa) 几乎恒定。这些结果与微观结构图像以及刘等人单独报告的数据一致。 [翻译。 IChemE Part C 80 (2002) 286]使用显微操作技术。完全去除管流中的糊状物所需的液体速度是根据临界剪切应力计算的，结果发现，该速度高于就地清洗装置建议的速度范围下限，但数量级相同。因此，FDG 能够现场测量沉积物宏观层的厚度及其机械性能。 (C) 2004 Elsevier Ltd. 保留所有权利。
Fluid dynamic gauging (FDG) is a technique for the measurement of the thickness of soft deposit layers on solid surfaces immersed in a liquid environment, in situ and in real time. The technique has been extended using computational fluid dynamics (CFD) simulations of the laminar gauging flow to quantify the stresses imposed on the material being gauged. CFD results were validated by comparison with experimental values for (i) the hydrostatic head, (ii) the nozzle discharge coefficient and (iii) the normal stresses acting on the gauged surface. The shear stress distribution predictions were subsequently used to determine the shearing yield strength of a soft food deposit. Layers of tomato paste (similar to2 mm thick) on stainless steel discs were aged by oven drying at 100 degreesC, and the removal characteristics studied. The shearing yield strength increased with drying time up to 3.0 h, after which the strength (13 Pa) was almost constant. These results are consistent with micro-structural images, and data reported separately by Liu et al. [Trans. IChemE Part C 80 (2002) 286] using a micro-manipulation technique. The liquid velocities required to fully remove the pastes in pipe flows were calculated from the critical shear stresses and were found to be higher than, but of the same order as, the lower limit of the range of velocities suggested for cleaning-in-place installations. FDG is therefore capable of measuring both the thickness of deposit macro-layers and their mechanical properties in situ. (C) 2004 Elsevier Ltd. All rights reserved.