The flow of cream through narrow glass tubes
The flow of cream through narrow glass tubes
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DOI：
10.1021/j150394a004
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发表时间：
1939-10-01
影响因子：
--
通讯作者：
Wagstaff, A
中科院分区：
文献类型：
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作者：
Blair, GWS;Hening, JC;Wagstaff, A
牛奶、奶油和冰淇淋混合物的流动特性研究相对较少。贝特曼和夏普(2)证明，在有限的应力范围内，冰淇淋混合物的流动率与剪切应力呈线性关系，但不成正比；在另一篇论文(3)中，他们表明各种牛奶的粘度随着应力的增加而下降，还表明，由于剪切而降低的粘度，在静置样品后再次上升。最后一种现象(“假身体”)，他们将其归因于脂肪块条件的变化。这些作者在25摄氏度下工作，他们提出，在低温度下，剪切产生的粘度下降比在高温下更明显。Mohr和Oldenburg(13)使用各种类型的恒流计(旋转圆柱体、毛细管和下落圆柱体)对牛奶和奶油进行了非常彻底的流变学研究。为了解释他们的数据，他们使用了一个Ostwald-de Waele类型的方程，其中剪应力的对数与剪切率的对数相对应。在一定的有限应力范围内，用这种方法得到的曲线是线性的，但所用的应力范围太宽了，以至于许多数据都超出了曲线的线性部分。12Mohr和Oldenburg也研究了粘度-浓度关系，最近在Leighton和他的同事(8，9，10，11，12)的手中得到了一个非常有趣的处理，但这个问题在本文中没有讨论。然而，在Leigh-ton的一些论文中，作者确实声称流量与剪应力之间存在线性关系。已经做了一定数量的其他工作，但有人认为，奶油和牛奶在窄管中流动的整个性质的问题需要进一步调查，而且这种调查的结果很可能导致测量这些系统的物理性质的方法，这将具有商业意义。
The flow properties of milk, cream, and ice-cream mixes have been comparatively little studied. Bateman and Sharp (2) showed that, for ice-cream mixes over a limited range of stress, the rate of flow was linearly related, but not proportional, to theshearing stress; in another paper (3) they showed that the viscosity of various kinds of milk fell with increasing stress, and also that the viscosity, reduced by shearing, rose again on resting the sample. This last phenomenon (“false body”) they ascribed to changes in the conditions of the fat clumps. These authors worked at 25 C., and they suggested that the fall in viscosity produced by shearing is more marked at low than at high temperatures. Mohr and Oldenburg (13) made a very thorough rheological study of milk and cream, using eonsistometers of various types (rotating cylinder, capillary, and falling cylinder). To interpret their data they used an equa-tion of the Ostwald-de Waele type, in which the logarithm of the shearing stress is plotted against the logarithm of the rate of shear. Over a certain limited stress range, curves obtained in this way are linear, but the range of stresses used was so wide that many of the datafell outside the linear part of the curve. 1 2Mohr and Oldenburg also investigated the viscosity-concentration relation, which has recently received a very interesting treatment at the hands of Leighton and his coworkers (8, 9, 10, 11, 12), but this problem is not discussed in the presentpaper. In some of Leigh-ton’s papers, however, the authors do claim a linear relation between flow rate and shearing stress. A certain amount of other work has been done (20), but it was felt that the whole question of the nature of the flow of cream and milk through narrow tubes required further investigation, and that the resultsof such an investigation might well lead to methods of measuring the physical properties of these systems which would be of commercial importance.