14,315 research outputs found
Numerical simulation of spray coalescence in an eulerian framework : direct quadrature method of moments and multi-fluid method
The scope of the present study is Eulerian modeling and simulation of
polydisperse liquid sprays undergoing droplet coalescence and evaporation. The
fundamental mathematical description is the Williams spray equation governing
the joint number density function f(v, u; x, t) of droplet volume and velocity.
Eulerian multi-fluid models have already been rigorously derived from this
equation in Laurent et al. (2004). The first key feature of the paper is the
application of direct quadrature method of moments (DQMOM) introduced by
Marchisio and Fox (2005) to the Williams spray equation. Both the multi-fluid
method and DQMOM yield systems of Eulerian conservation equations with
complicated interaction terms representing coalescence. In order to validate
and compare these approaches, the chosen configuration is a self-similar 2D
axisymmetrical decelerating nozzle with sprays having various size
distributions, ranging from smooth ones up to Dirac delta functions. The second
key feature of the paper is a thorough comparison of the two approaches for
various test-cases to a reference solution obtained through a classical
stochastic Lagrangian solver. Both Eulerian models prove to describe adequately
spray coalescence and yield a very interesting alternative to the Lagrangian
solver
The XDEM Multi-physics and Multi-scale Simulation Technology: Review on DEM-CFD Coupling, Methodology and Engineering Applications
The XDEM multi-physics and multi-scale simulation platform roots in the Ex-
tended Discrete Element Method (XDEM) and is being developed at the In- stitute
of Computational Engineering at the University of Luxembourg. The platform is
an advanced multi- physics simulation technology that combines flexibility and
versatility to establish the next generation of multi-physics and multi-scale
simulation tools. For this purpose the simulation framework relies on coupling
various predictive tools based on both an Eulerian and Lagrangian approach.
Eulerian approaches represent the wide field of continuum models while the
Lagrange approach is perfectly suited to characterise discrete phases. Thus,
continuum models include classical simulation tools such as Computa- tional
Fluid Dynamics (CFD) or Finite Element Analysis (FEA) while an ex- tended
configuration of the classical Discrete Element Method (DEM) addresses the
discrete e.g. particulate phase. Apart from predicting the trajectories of
individual particles, XDEM extends the application to estimating the thermo-
dynamic state of each particle by advanced and optimised algorithms. The
thermodynamic state may include temperature and species distributions due to
chemical reaction and external heat sources. Hence, coupling these extended
features with either CFD or FEA opens up a wide range of applications as
diverse as pharmaceutical industry e.g. drug production, agriculture food and
processing industry, mining, construction and agricultural machinery, metals
manufacturing, energy production and systems biology
- …