期刊名称：International Journal of Innovative Research in Science, Engineering and Technology
印刷版ISSN：2347-6710
电子版ISSN：2319-8753
出版年度：2016
卷号：5
期号：11
页码：20125
DOI：10.15680/IJIRSET.2016.0511137
出版社：S&S Publications
摘要：Based on a numerical study of the potential flow through contractions of chosen geometry, a method isgiven to obtain the shape of contraction which gives small adverse pressure gradients and low non uniformity in thevelocity distribution at the exit. From the literature that we have read, we concluded that It may be observed that, due tolarge acceleration, nozzles with large contraction ratios are tolerant to any irregularities at the low velocity end, such asseparation-induced thick boundary layers and unsteadiness. On the other hand, nozzles with smaller CR (say 4 or 5)demand greater attention to be given to avoid separation. Thus,a contraction with area ratio of eight is taken anddesigned using two and three degrees equations of and is investigated experimentally. There are two criteria whichhave to be satisfied at the narrow end of a nozzle: the maximum acceptable flow nonuniformity and the avoidance ofseparation. In most practical cases, the nonuniformity, will be required to be no more than 2 percent.It is found that there is no separation of flow, the thickness of the boundary layer at the exit is small and the nonuniformityin velocity at the exit is small. The procedure consists of first computing the potential flow field and hencethe pressure distributions along the walls of a contraction of given size and shape. Thus, an iterative design procedurehas been followed to construct a small, low-speed wind tunnel.
