Effects of Non-homogeneously Distributed Roughness on Turbulent Pipe Flow

这项建议解决了对水力发电行业至关重要的一个问题：首次提供非均匀分布的粗糙度元素的压降数据。这些数据很重要，因为管道中粗糙度元素的当前数据仅限于均匀的沙粒型粗糙度，或者是均匀但稀疏分布在表面上的粗糙度。魁北克水电公司注意到，在其许多水电压力钢管作业中，在三十年的时间框架内，形成了间距不均匀、分布不均匀的粗糙度元素，导致水头(压力)下降，进而导致发电量下降，从而造成数百万美元的收入损失。该项目将支持一名硕士研究生的培训。两年以上的学生和四年以上的博士生将进行一系列仔细的实验，以量化这些损失，并得出描述不均匀粗糙度对表面摩擦(压力损失)影响的相关性，从而使魁北克水电能够更好地评估何时进行压力管道清洗。产生的数据将填补我们在非均匀间隔和非均匀分布的粗糙元素的影响方面的知识的一个明显空白。这些数据对科学界来说将是新的，并将产生大量的档案出版物。这些数据虽然对魁北克水电至关重要，但将通过科学文献传达给加拿大的其他水电站，从而有助于提高加拿大的水电生产效率，并为安排压力钢管维护提供关键信息，以实现最大的效益-成本比。

This proposal addresses a problem of critical importance to the hydroelectric power industry: to provide for the first time pressure drop data for non-homogeneously distributed roughness elements. These data are important as current data for roughness elements in pipes are restricted to uniform sand-grain type roughness or for roughness that is uniformly but sparsely distributed on a surface. Hydro Quebec have noted that in many of their hydro-electric penstock operations, that over a thirty year time frame, non-uniformly spaced and non-homogeneously distributed roughness elements are formed that gives rise to a drop in head (pressure) that translates into lowered electricity production with the concomitant loss of millions of dollars in revenue. This project will support the training of one M.A.Sc. student over two years and one Ph.D. student over four years, who will carry out a careful set of experiments to quantify these losses and to derive correlations that describe the effects of non-uniform roughness on skin friction (pressure loss) from which Hydro Quebec will then be in a better position to assess when to perform penstock cleaning. The data generated will fill a glaring gap in our knowledge on the effects of non-uniformly spaced and non-homogeneously distributed roughness elements. These data will be new to the scientific community and will generate numerous archival publications. These data, while of critical importance to Hydro Quebec will be communicated to other hydro-electricity generators in Canada through the scientific literature, and thereby will help improve Canada's overall hydro-electricity production efficiency as well as to provide critical information for scheduling penstock maintenance to achieve maximum benefit-to-cost.