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Parameter Formulation – Characterize Collision Potential

Introduction

The formulation of parameters

Latex
\large$\theta \varepsilon ^{1/3} $
,
Latex
\large$K_{baffle} $
,
Latex
\large$\Pi _{cell} $
and are described below, for characterizing flocculation potential using numerical solutions from CFD simulations. Note that this is a work in progress, so the notation of variables and interpretation of equations still need to be further clarified.

Latex
\large$\theta \varepsilon ^{1/3} $
:
Calculating a flow weighted average of
Latex
\large$\theta \varepsilon ^{1/3} $
:
Latex
\large${\theta _{baffle}}{\varepsilon ^{{\raise0.7ex\hbox{$1$} \!\mathord{\left/
{\vphantom {1 3}}\right.\kern-\nulldelimiterspace}
\!\lower0.7ex\hbox{$3$}}}} = {1 \over Q}\sum\limits_{fe} {{\theta _{fe}}\varepsilon _{fe}^{{\raise0.7ex\hbox{$1$} \!\mathord{\left/
{\vphantom {1 3}}\right.\kern-\nulldelimiterspace}
\!\lower0.7ex\hbox{$3$}}}{Q_{fe}}}$
, where
Latex
\large$${\theta _{fe}} = {{{\forall _{fe}}} \over {{Q_{fe}}}} = {{\Delta x\Delta y} \over {\left| {{v_x}\Delta y} \right| + \left| {{v_y}\Delta x} \right|}}$$
,
Thus
Latex
\large$${\theta _{baffle}}{\varepsilon ^{{\raise0.7ex\hbox{$1$} \!\mathord{\left/
{\vphantom {1 3}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$3$}}}} = {1 \over Q}\sum\limits_{fe} {{\forall _{fe}}\varepsilon _{fe}^{{\raise0.7ex\hbox{$1$} \!\mathord{\left/
{\vphantom {1 3}}\right.\kern-\nulldelimiterspace}
\!\lower0.7ex\hbox{$3$}}}} $$

Latex
\large
${K_{baffle}}$
:

Latex
\large
$${\varepsilon _{fe}} = {{g{h_l}} \over {{\theta _{fe}}}}$$
Latex
\large
$${h_e} = {K_{baffle}}{{{V^2}} \over {2g}}$$
Latex
\large
$${h_l} = {{{\varepsilon _{fe}}{\theta _{fe}}} \over g}$$

Latex
\large
$${K_{baffle}} = {h_e}{{2g} \over {{V^2}}}$$

where

Latex
\large
$${\theta _{fe}} = {{{\forall _{fe}}} \over {{Q_{fe}}}} = {{\Delta x\Delta y} \over {\left| {{v_x}\Delta y} \right| + \left| {{v_y}\Delta x} \right|}}$$


Latex
\large
$${K_{baffle}} = {1 \over Q}\sum\limits_{fe} {{{{\varepsilon _{fe}}{\theta _{fe}}} \over g}{{2g} \over {{V^2}}}{Q_{fe}}} $$


Latex
\large
$${K_{baffle}} = {2 \over {Q{V^2}}}\sum\limits_{fe} {{\varepsilon _{fe}}{\forall _{fe}}} $$


Latex
\large
$${K_{baffle}} = {2 \over {bw{V^3}}}\sum\limits_{fe} {{\varepsilon _{fe}}{\forall _{fe}}} $$



where

Latex
\large
$$Q = Vbw$$

Latex
\large
${\Pi _{cell}}$
:
Latex
\large
$${\varepsilon _{cell}} = {{{K_{baffle}}{V^3}} \over {2{\Pi _{cell}}b}}$$
, plug in

Latex
\large
${K_{baffle}}$

and simplify:

Latex
\large
$${\Pi _{cell}} = {1 \over {{b^2}w}}{{{{\left( {\sum\limits_{fe} {{\forall _{fe}}\varepsilon _{fe}^{{\raise0.7ex\hbox{$1$} \!\mathord{\left/
{\vphantom {1 3}}\right.\kern-\nulldelimiterspace}
\!\lower0.7ex\hbox{$3$}}}} } \right)}^{{\raise0.7ex\hbox{$3$} \!\mathord{\left/
{\vphantom {3 2}}\right.\kern-\nulldelimiterspace}
\!\lower0.7ex\hbox{$2$}}}}} \over {{{\left( {\sum\limits_{fe} {{\forall _{fe}}{\varepsilon _{fe}}} } \right)}^{{\raise0.7ex\hbox{$1$} \!\mathord{\left/
{\vphantom {1 2}}\right.\kern-\nulldelimiterspace}
\!\lower0.7ex\hbox{$2$}}}}}}$$

Latex
\large
$G\theta $
:

Latex
\large
$$G{\theta _{baffle}} = {1 \over Q}\sum\limits_{fe} {{G_{fe}}{\theta _{fe}}{Q_{fe}}} $$


Latex
\large
$${\theta _{fe}} = {{{\forall _{fe}}} \over {{Q_{fe}}}} = {{\Delta x\Delta y} \over {\left| {{v_x}\Delta y} \right| + \left| {{v_y}\Delta x} \right|}}$$


Latex
\large
$$G{\theta _{baffle}} = {1 \over Q}\sum\limits_{fe} {{G_{fe}}{\forall _{fe}}} $$


Latex
\large
$${G_{fe}} \propto \sqrt {{{{\varepsilon _{fe}}} \over \nu }} $$


Latex
\large
$$G{\theta _{baffle}} = {1 \over Q}\sum\limits_{fe} {\sqrt {{{{\varepsilon _{fe}}} \over \nu }} {\forall _{fe}}} $$


Latex
\large
$$G{\theta _{baffle}} = {1 \over {Q\sqrt \nu  }}\sum\limits_{fe} {\varepsilon _{fe}^{{\raise0.7ex\hbox{$1$} \!\mathord{\left/
{\vphantom {1 2}}\right.\kern-\nulldelimiterspace}
\!\lower0.7ex\hbox{$2$}}}{\forall _{fe}}} $$

All parameters are calculated from summing over all nodes (finite element)

Latex
\large
$$\sum {{\forall _{fe}}\varepsilon _{fe}^{{\raise0.7ex\hbox{$1$} \!\mathord{\left/
{\vphantom {1 3}}\right.\kern-\nulldelimiterspace}
\!\lower0.7ex\hbox{$3$}}}} $$
,
Latex
\large
$$\sum {{\forall _{fe}}\varepsilon _{fe}^{{\raise0.7ex\hbox{$1$} \!\mathord{\left/
{\vphantom {1 2}}\right.\kern-\nulldelimiterspace}
\!\lower0.7ex\hbox{$2$}}}} $$
,
Latex
\large
$$\sum {{\forall _{fe}}{\varepsilon _{fe}}} $$
, which can be calculated using the following UDF script:performance.c.