Environmental Engineering Reference
In-Depth Information
transformation of mercury species (limited to gaseous mercury compound) during
the coal combustion process, based on the CFD model-FLUENT6.2 as a platform,
incorporated with a mercury species sub-model. Initially, 3-D distributions of
temperature, velocity and components were to be simulated as a basis, mercury
simulation would be given accordingly, coupled with the mercury sub-model. This
self-developed empirical model was validated for mercury simulation in the fur-
nace. The result was to be stretched, in combination with a 1-D kinetics model of
the heating surface after the furnace, as well as CEM
in-situ
measurement of mer-
cury species concentrations at a real 250 MW pulverized coal boiler.
4.5.1.1 CFD Introduction
The development of modern CFD began with the advent of the digital computer in
the early 1950s. It is one of the branches of fluid mechanics that uses numerical
methods and algorithms to solve and analyze problems that involve fluid flows.
Computers are used to perform the millions of calculations required to simulate the
interaction of liquids and gases with surfaces defined by boundary conditions. Even
with high-speed supercomputers only approximate solutions can be achieved in
many cases.
The essence of CFD is to discretize the governing equations at a fixed compu-
tational domain based on point (for example, finite difference method) or volume
(for example, finite element and finite volume methods), convert them to algebraic
equations defined at each computational grid and volume, and then solve these
algebraic equations by way of iteration.
The simulation work was conducted with the aid of FLUENT6.2 code. For over
twenty years, Fluent has been a leader in the development of CFD software for
simulating fluid flow, heat and mass transfer, and a host of related phenomena
involving turbulence, reactions, and multiphase flow. But with the acquisition of
Fluent by ANSYS, Inc. (NASDAQ: ANSS), additional state-of-the-art computa-
tional fluid dynamics (CFD) technology will be incorporated into the impressive
ANSYS suite of CAE simulation solutions. The finite volume method (FVM) is the
classical or standard approach used most often in commercial software and research
codes, including in FLUENT.
The design of FLUENT6.2 is based on the concept of a computer software
cluster, which aims to solve problems with suitable computational speed, stability
and accuracy according to the characteristics of the problem.
A CFD software cluster is composed of different software from different fields.
The construction of a CFD software cluster solves the problems involved in the
computation of complicated flow in each field and makes data exchange more
efficient and convenient due to the unified fore-end and rear-end treatment tools.
This forms the basis for the general utilization of FLUENT. ANSYS FLUENT
software contains the broad physical modeling capabilities needed to model flow,
turbulence, heat transfer, and reactions for industrial applications ranging from air
flow over an aircraft wing to combustion in a furnace, from bubble columns to oil
Search WWH ::
Custom Search