Spreadsheet Calculations for Jets in Crossflow From Single and Opposed Rows With Alternating Hole Sizes

Abstract

The primary purpose of this study was to show the expected results for cases of single and opposed rows of jets from alternating large and small round holes. Previous publications demonstrated that the NASA empirical model gave results that were an excellent representation of mean experimental scalar results and that the model could confidently be used to investigate configurations for which results have not been published in the open literature. Calculations for cases of opposed rows of jets that would overpenetrate slightly in an inline configuration showed that better mixing was attained when one row was shifted to make a staggered configuration so that a small hole was opposite from a larger one. However, the result was no better than for an optimum inline configuration with all the holes of the same size. Staggering the rows does not make much difference in an optimum inline configuration. For all cases investigated, the dimensionless variance of the mixture fraction decreased significantly with increasing downstream distance, but, at a given downstream location, the variation between cases was small.