Patent ID: 8608826
Filing Date: 2013-12-17
Classification: B03C

Abstract:
1. A computer-implemented method of modeling fly ash collection efficiency in wire-duct electrostatic precipitators, comprising the steps of: (a) modeling a monopolar corona of a wire-duct electrostatic precipitator as ∇·{right arrow over (E)}=ρ/∈ (b) generating a finite element boundary fitted grid matching a geometry of the wire-duct electrostatic precipitator, wherein the finite element boundary fitted grid is generated from an intersection of electric field lines, emanating from M finite element nodes selected on a circumference of each of the discharging wires, and N equipotential contours, wherein the intersection of the electric field lines with the N equipotential contours defines a plurality of quadrilaterals; (c) calculating a set of estimated electric field magnitude values E at the M finite element nodes; (d) dividing each of the quadrilaterals into a pair of triangles to generate a plurality of triangular finite elements; (e) estimating the particle charge density ρ (f) establishing a plurality of flux tubes in the finite element boundary fitted grid respectively about the plurality of electric field lines such that ionic space charges flow along centers of the plurality of flux tubes; (g) estimating the ionic charge density ρ wherein {circumflex over (l)} is a unit vector along an axis of the flux tube; (h) approximating the potential φ within each of the finite elements as a linear function of coordinates as φ=φ (i) estimating a nodal potential error e (j) correcting an ionic space charge density ρ (k) repeating steps (e) through (j) until the maximum value of e (l) regenerating the finite element boundary fitted grid and repeating steps (e) through (j) until self-consistent solutions for φ and ρ are obtained and a maximum difference between ionic space charge densities at the finite element nodes is less than a second threshold value δ (m) calculating a corona current I for each discharging wire as wherein J i represents per-unit current density at the i-th flux tube and A i,1 represents a corresponding per-unit cross-sectional area; and (n) calculating precipitator efficiency as wherein C in and C out represent particle concentration at a precipitator inlet and outlet, respectively, and are given by where S e represents a total collecting surface area and Q represents a gas flow rate; wherein steps (a) through (n) are performed on a computer.