Abstract
The stability boundaries of a single flexible tube in one of the first rows of a tube bundle can be highly dependent on the turbulence characteristics of the upstream flow. For certain bundle geometries, increased turbulence yields a stabilization of a flexible tube in the critical row. If this stabilization also occurs on the more realistic condition of a fully flexible bundle, it could be a useful effect with respect to applications. The flow rate in a heat exchanger could be increased or existing stability problems could easily be solved by inserting turbulence grids at the inlet instead of changing the entire tube bundle. Therefore, wind tunnel tests have been carried out with various flexible tubes in the tube bundle. The vibrations in the tube bundle have been carefully observed and measured by means of accelerometers. These investigations still show a significant stabilizing effect of increased upstream turbulence. For a better understanding of the observed effects some theoretical investigations on the stability behavior of a relatively simple “tube-in-channel-flow” model for a single flexible tube have been performed. Here, a stabilizing effect of a disturbed flow velocity has been found which is similar to the effect observed in the experiments.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have