In this study the influence of the exit tube geometry on the overall flow properties of cyclones is investigated using detached eddy simulation. The results for different exit pipe shapes and lengths reveal that under certain conditions the outlet has an upstream effect on the flow behaviour within the cyclone. This can in turn result in poor build-up of swirl in the crucial region of the cyclo...

The presence of swirl in combustion systems produces a marked change their boundary layer flashback behaviour. Two aspects swirling flow are investigated this study: the effect swirl-generated wall-normal pressure gradient, and misalignment between mean direction flame propagation. analysis employs Direct Numerical Simulation (DNS) fuel-lean premixed hydrogen-air flames turbulent planar channel...

Swirling flows are of considerable practical importance. They used for example to increase heat transfer in pipes or stabilize flames at a distance from the injector unit by means central reverse flow that establishes an inner recirculation zone hot combustion products. The level swirl is governed dimensionless parameter designated as number, which essentially quantifies ratio axial component r...

In this paper, we study the 3D axisymmetric Navier-Stokes Equations with swirl. We prove the global regularity of the 3D Navier-Stokes equations for a family of large anisotropic initial data. Moreover, we obtain a global bound of the solution in terms of its initial data in some Lp norm. Our results also reveal some interesting dynamic growth behavior of the solution due to the interaction bet...

We present simulations of a laboratory-scale low swirl burner fueled with hydrogen at atmospheric pressure. The study uses detailed chemistry and transport including a submechanism for computing nitrogen emissions. The simulation shows how the cellular burning structures characteristic of lean premixed hydrogen combustion lead to enhancements in the NOx emissions from these flames. Analysis of ...

Weobtain improved regularity criteria for the axisymmetricweak solutions of the three dimensional Navier-Stokes equations with nonzero swirl. In particular we prove that the integrability of single component of vorticity or velocity fields, in terms of norms with zero scaling dimension give sufficient conditions for the regularity of weak solutions. To obtain these criteria we derive new a prio...

The objectives of this study were to estimate heritability for scrotal circumference (SC) and semen traits and their genetic correlations (rg) with birth weight (BRW). Semen traits were recorded for Line 1 Hereford bulls (n = 841), born in 1963 or from 1967 to 2000, that were selected for use at Fort Keogh (Miles City, MT) or for sale. Semen was collected by electroejaculation when bulls were a...

This paper provides an overview of recent advances in the theoretical modeling and numerical simulation of cryogenic fluid injection and mixing in transcritical and supercritical environments. The basis of the analysis is a general theoretical and numerical framework that accommodates full conservation laws and real-fluid thermodynamic and transport phenomena. All of the thermophysical properti...

A preliminary study of atomization mechanisms in gas-centered swirl-coaxial injectors for use in rocket engines has been undertaken. Gas-centered swirl-coaxial injectors differ from other injectors in that atomization occurs from a wall-bounded liquid. Few studies of atomization mechanisms in wall-bounded flows exist; some probable atomization processes have been determined, however. These mech...