Papers by Keyword: Small Diameter Tube

Abstract: In recent years, the small diameter aluminium tube has been widely utilized for chemical instruments and medical devices. These instruments are should be minimized since the usage of the small diameter tubes has been extremely increased. However, the deformation characteristics could not be scaled down similarly to the material dimensions due to the size effect. Thus, tube bulge forming is necessary to clarified the deformation characteristics of the small diameter tubes. In this paper, the formability of the warm tube bulge forming by using the small diameter A1100 aluminium tube with 2.0 mm outer diameter and 0.2 mm thickness has been investigated. As the results, the effect of the different temperature and the different internal pressure on the tube bulge forming of the small diameter A1100 aluminium tubes was clarified. Furthermore, it was confirmed that the variation of the internal pressure loading rate affected the deformation characteristics of the tubes.

Abstract: An experimental study has been carried out using a tube bank representing a section of a tube bundle. The bank comprised 3 columns each of 10 stainless steel electrically heated tubes of 3mm outside diameter with pitch to diameter ratio of 1.5 in an in-line arrangement. Flow rate through the test section was controlled. Each tube in the central column was instrumented to permit determination of the tube temperature and heat flux, hence permitting calculation of the heat transfer coefficient. These tests were carried out using distilled water at nominal atmospheric pressure over a range of heat fluxes between 6 - 21 kW/m2. Results of the heat transfer tests are presented and compared with correlations used for conventionally sized bundles. Correlations developed for large tube bundle overestimate the experimental results.