Investigation of the secondary flow in two research facilities Free

The purpose of this article is to introduce various ways of experimental investigation of the behaviour and creation of the secondary flow in turbomachines. First of all, the text focuses on the theory of the secondary flow: what it is, where does it occur and what is the cause of it. It is followed by the analysis of individual experiments and their description. The mentioned experiments were carried out in Europe and in the USA. They, for example, examine the analogy between the mass and the heat flow, the increase of turbulence intensity due to the secondary flow affecting it or the influence of aspect ratio. The results show, that when observing the mass flow instead of the heat flow, it is possible to examine the area of interest in more detail and then transfer the results for the purpose of heat flow anticipation. During this experiment, it was also observed, that the turbulence intensity increases by 31% in average as a result of the secondary flow phenomena. The second experiment shows the influence that aspect ratio has on vortex creation. This article shows the secondary flow problematic, its consequences and the presentation of disparate approaches of how to research those phenomena.