Williams D M, Mein G A
J Dairy Res. 1986 May;53(2):179-85. doi: 10.1017/s0022029900024778.
The velocity of milk flow from the teat during the peak flow rate period of milking was estimated to be approximately 8.5 m/s with a liner vacuum of 50 kPa and 7.5 m/s at 40 kPa. These results confirm the applicability of the Bernoulli theorem for estimating velocity of milk flow through the teat canal during milking. Concurrent measurements of mass flow rate and velocity indicate that the effective diameter of the open teat canal is approximately 2 mm. Further calculations indicate that the shear force due to milk flow acting to debride the surface of the open teat canal is about 1.8 X 10(-2) N. The opposing surfaces of the 'closed' teat canal may be approximately 100 micron apart immediately after milking. If so, bacteria present in the milk residue within the teat canal would never be more than 50 micron from a surface.
在挤奶的流量高峰期，当内衬真空度为50千帕时，估计牛奶从乳头流出的速度约为8.5米/秒，40千帕时为7.5米/秒。这些结果证实了伯努利定理在估算挤奶期间通过乳头管的牛奶流速方面的适用性。质量流速和速度的同步测量表明，开放乳头管的有效直径约为2毫米。进一步计算表明，牛奶流动产生的用于清创开放乳头管表面的剪切力约为1.8×10⁻²牛。挤奶后，“闭合”乳头管相对的表面可能相距约100微米。如果是这样，乳头管内牛奶残留中存在的细菌距离表面永远不会超过50微米。
