Analysis of a cross-flow influence for a turbulence progress in an initial segment of axisymmetric duct

Poznan University of Technology, Chair of Thermal Engineering, Piotrowo 3 Street, 60-965 Poznań, Poland

^* Corresponding author: wojciech.judt@put.poznan.pl

Abstract

Influence for a nondisturbed stream by cross-flow is present in many technical applications. In part of applications, this phenomenon is caused intentionally, but in others, it is a side-effect. Flow through the closed duct is one of the most frequently realized types of flow in thermal devices. The paper shows an influence of cross-flow for a laminar stream, which is flowing through closed, round duct. The considered case was calculated in numerical calculations and analyzed during experimental research. Cross-flow stream was generated by four circular nozzles located on the duct walls in some distance from the duct inlet, which was distributed along the circumference of analyzed construction in the right angle to the mainstream. Experimental research was realized by a constant temperature anemometry measurement method. A numerical model of a fluid flow was created in ANSYS Fluent software. Unsteady numerical calculations of a cross-flow influence for a mainstream was realized with the Detached Delayed Eddy Dissipation model of turbulence application. Realized research established how a cross stream can turbulent a laminar flow in a closed, circular duct. Authors showed velocity distribution in the main duct after cross-flow influence and demonstrated, that this method allows ascending turbulence of a flow in external parts of fluid flow.