The paper presents large eddy simulation of unconfined swirling jets. In the first part, an unconfined annular jet is investigated for swirl numbers ranging from 0 to 1.2. The impact of the swirl on the mean flow and the precessing vortex structures in this flow is analysed. In the second part of the paper, a co-annular pilot jet is introduced near the axis. The investigations show that the add...

The central recirculation zone (CRZ) in a swirl stabilized gas turbine combustor has a dominant effect on the fuel air mixing process and flame stability. Most of state of the art swirlers share one disadvantage; the fixed swirl number for the same swirler configuration. Thus, in a mathematical sense, Reynolds number becomes the sole parameter for controlling the flow characteristics inside the...

The objective of this work is to investigate the turbulent reacting flow in a three dimensional combustor with emphasis on the effect of inlet swirl flow through a numerical simulation. Flow field is analyzed using the SIMPLE method which is known as stable as well as accurate in the combustion modeling, and the finite volume method is adopted in solving the radiative transfer equation. In this...

This paper reviews the efforts to construct (or prove the impossibility of) singular solutions of the Euler equations for three dimensional incompressible flow. A semi-analytic approach to this problem is formulated based on numerical computation of complex traveling wave solutions, followed by perturbation construction of a real solution, for axisymmetric flow with swirl. The perturbation anal...

Solids removal across two settling devices, i.e., a swirl separator and a radial-flow settler, and across a microscreen drum filter was evaluated in a fully recirculating system containing a single 150 m ‘Cornell-type’ dual-drain tank during the production of food-size Arctic char and rainbow trout. The flow through the culture tank was 4500–4800 L/min. Approximately 92–93% of the system flow e...

When a fluid enters a rotating circular pipe, an angular momentum or swirl boundary layer appears at the wall and interacts with the axial momentum boundary layer. In the centre of the pipe, the fluid is free of swirl and is accelerated due to boundary layer growth. Below a critical flow number, defined as the ratio of average axial velocity to circumferential velocity of the pipe, there is flo...

In order to evaluate different port concepts for modern Compression-Ignition engines, usually quantities as the swirl level and the flow coefficient are evaluated, which are measured on a stationary flow test bench. As additional criterion, in this work, the homogeneity of the swirl flow is introduced and defined quantitatively. Different valve lift strategies are evaluated using three-dimensio...

The effect of swirling on the flow characteristics of tubes with sudden expansion is experimentally examined by 3D particle image velocimetry(PIV) technique to determine velocity profiles. The swirling flow of water in sudden 1:2 axisymmetric expansion has been previously studied within a horizontal round tube. A tangential slot is used as a swirl generator for swirling flow, whereas a honey co...

ABSTRACT An axisymmetric, turbulent, multigrid computational fluid dynamics (CFD) code is used, on a parallel computing facility, to predict the mixing between superposed flows in a pre−swirl rotor−stator system, being a simplified representation of the internal air cooling system in gas turbine engines. Strong recirculations formed by the pre−swirl cross−flow lead to entrainment of disc−coolin...