Yates C C, McWilliams B J, Vallino L D
School of Engineering, University of Pittsburgh, PA 15261.
Cleft Palate J. 1990 Apr;27(2):193-8; discussion 198-9. doi: 10.1597/1545-1569(1990)027<0193:tpfmsf>2.3.co;2.
The pressure-flow method introduced by Warren and DuBois is a useful method for estimating velopharyngeal orifice area. However, this investigation shows that unless geometric similarity of subject and model exists, the value of the flow coefficient k used in the equation to estimate velopharyngeal orifice area cannot be established from model tests. Use of k = 0.65 is questioned as that value is typical of thin plate orifices, a geometry that is not a good representation of the velopharyngeal passage. Values of k from the literature and from steady state tests using a model similar to Warren's are presented to show the effect of various inlet shapes. The influence of inlet shape supports the conclusion that k may be significantly higher than 0.65, conceivably approaching values in the range of 0.9 to 0.97, depending on the orifice geometry.
沃伦和杜波依斯提出的压力-流量法是估算腭咽孔面积的一种有用方法。然而，本研究表明，除非受试者与模型存在几何相似性，否则用于估算腭咽孔面积的方程中所使用的流量系数k的值无法通过模型试验确定。k = 0.65的使用受到质疑，因为该值是薄板孔口的典型值，而这种几何形状并不能很好地代表腭咽通道。文中给出了文献中的k值以及使用与沃伦的模型相似的模型进行稳态试验得到的k值，以展示各种入口形状的影响。入口形状的影响支持了这样一个结论，即k可能显著高于0.65，根据孔口几何形状的不同，k值可能接近0.9至0.97的范围。
