presentation slides for chapter 17, part 2 of fundamentals of atmospheric modeling 2 nd edition

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Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd Edition Mark Z. Jacobson partment of Civil & Environmental Engineerin Stanford University Stanford, CA 94305-4020 [email protected] April 1, 2005

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Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd Edition. Mark Z. Jacobson Department of Civil & Environmental Engineering Stanford University Stanford, CA 94305-4020 [email protected] April 1, 2005. Solvation and Hydration. Solvation - PowerPoint PPT Presentation

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Page 1: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Presentation Slides for

Chapter 17, Part 2of

Fundamentals of Atmospheric Modeling 2nd Edition

Mark Z. JacobsonDepartment of Civil & Environmental Engineering

Stanford UniversityStanford, CA [email protected]

April 1, 2005

Page 2: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Solvation and HydrationSolvation

Bonding between solvent and solute in solution

Hydration

When solvent is liquid water, solvation is hydration

Hydration of cations --> lone pairs of electrons on oxygen atom of water attach to cations

Hydration of anions --> water molecule attaches to anion via hydrogen bonding

Page 3: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Water EquationQuantify amount of hydration with empirical water equation

Zdanovskii-Stokes-Robinson (ZSR) equation

Example with two species, x and y (17.64)

mx,a, my,a = molalities of x and y, alone in solution at given relative humidity

mx,m, my,m = molalities of x and y, when mixed together, at same relative humidity

mx,mmx,a

+my,mmy,a

=1

Page 4: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

ZSR Equation

Table 17.2

ZSR equation predictions for a sucrose (species x) - mannitol (species y) mixture at two different water activities.

mx,m/mx,a +

Case mx,a my,a mx,m my,m my,m/my,a

1 0.7751 0.8197 0.6227 0.1604 0.999

2 0.9393 1.0046 0.1900 0.8014 1.000

mx,mmx,a

+my,mmy,a

=1

Page 5: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Water EquationGeneralized ZSR equation (17.64)

Polynomial expression for molality of electrolyte alone in solution at a given water activity (17.66)

mk,mmk,ak

∑ =1

mk,a =Y0,k +Y1,kaw +Y2,kaw2 +Y3,kaw

3 +...

Page 6: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Water Equation

Fig. 17.4a

Water activities of several electrolytes at 298.15 K

0 10 20 30 40 50 60

0

0.2

0.4

0.6

0.8

1

0 10 20 30 40 50 60

Molality

Water activityNaNO

3

HNO

3

H

2

SO

4HCl

Wat

er a

ctiv

ity

Page 7: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Water Equation

Fig. 17.4b

Water activities of several electrolytes at 298.15 K

0 5 10 15 20 25 30

0.4

0.5

0.6

0.7

0.8

0.9

1

0 5 10 15 20 25 30

Molality

Water activity

NH

4

NO

3

NH

4

Cl

NaCl

(NH

4

)

2

SO

4

Na

2

SO

4

Wat

er a

ctiv

ity

Page 8: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Temp. Dependence of Water ActivityTemperature dependence of binary water activity coefficients under

ambient surface conditions is small.

Polynomial for water activity at reference temperature (17.68)

Temperature dependence of water activity (17.67)

lnaw T( ) =lnaw0 −

mvmk,a2

R*TLT0

∂φL∂mk,a

+TC∂φcP∂mk,a

⎝ ⎜

⎠ ⎟

lnaw0 =A0 +A1mk,a

12+A2mk,a +A3mk,a

32+...

Page 9: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Temp. Dependence of Water ActivityCombine (17.67), (17.68), (17.54) (17.69-70)

lnaw T( ) =A0 +A1mk,a12

+A2mk,a +E3mk,a32

+E4mk,a2 +...

El =Al −0.5 l −2( )mv

R*TLT0

Ul −2 +TCVl−2⎛

⎝ ⎜

⎠ ⎟

Example mHCl= 16 m

T = 273 K---> aw = 0.09

T = 310 K---> aw = 0.11

Page 10: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Practical Use of Water EquationRearrange (17.65) (17.71)

mi,j,a = binary molalities of species alone in solution ci,j,m = hypothetical mol cm-3 of electrolyte pair when mixed in solution with all other components

In a model, ion concentrations known but hypothetical electrolyte concentrations unknown --> find hypothetical concentrations

cw =1mv

ci, j,mmi, j,aj =1

NA

∑⎛

⎜ ⎜

⎟ ⎟

i=1

NC

Page 11: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Practical Use of Water Equation

6 mol m-3 of H+, 6 mol m-3 Na+

7 mol m-3 of Cl- , 5 mol m-3 of NO3-

Example 17.1:

Combine ions in a way to satisfy mole balance constraintscH+,m=cHNO3,m+cHCl,m

cNa+,m =cNaNO3,m+cNaCl,m

cCl−,m=cHCl,m+cNaCl,m

cNO3- ,m =cHNO3,m+cNaNO3,m

Case cHCl,m cHNO3,m cNaCl,m cNaNO3,m

1 6 0 1 52 4 2 3 3

Concentrations that satisfy mole balance constraints (Table 17.3)

Page 12: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Practical Use of Water Equation

Cation

Automatic method to recombine ions into hypothetical electrolytes

Execute the following three equations, in succession, for each undissociated electrolyte, i,j

Electrolyte (17.72)

Anion

ci, j,m=minci,mνi

,cj,mν j

⎝ ⎜ ⎜

⎠ ⎟ ⎟

ci,m=ci,m−νici, j,m

cj,m=cj,m−ν jci, j,m

Page 13: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Deliquescence Relative HumidityDeliquescence

Process by which a particle takes up liquid water, lowering its saturation vapor pressure

Deliquescence relative humidity (DRH)The relative humidity at which an initially-dry solid first takes on liquid water during an increase in relative humidity. Above the DRH, the solid may not exist.

Crystallization relative humidity (CRH)The relative humidity at which an initially-supersaturated aqueous electrolyte becomes crystalline upon a decrease in relative humidity.

Page 14: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Deliquescence Relative Humidity

Table 17.4

DRHs and CRHs for several electrolytes at 298 K

In a mixture, the DRH of a solid in equilibrium with the solution is lower than the DRH of the solid alone

Electrolyte DRH(%) CRH(%)

NaCl 75.28 47Na2SO4 84.2 57-59NaHSO4 52.0 <5NH4Cl 77.1 47(NH4)2SO4 79.97 37-40NH4HSO4 40 <5-22NH4NO3 61.83 25-32KCl 84.26 62Oxalic acid 97.3 51.8-56.7

Page 15: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Solid Formation

Consider the equilibrium reaction

Consider the equilibrium reaction

A solid forms when (17.73)

A solid forms when (17.74)

NH4NO3 s( ) NH4++NO3

mNH4

+mNO3−γ

NH4+,NO3

−2 >Keq T( )

NH4NO3 s( ) NH3 g( )+HNO3 g( )

pNH3 g( ),spHNO3 g( ),s >Keq T( )

Page 16: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Example Equilibrium ProblemConsider two equilibrium reactions (17.75)

HCl (g)H

+

+ Cl-

HSO4 H

+

+ SO

2-

4

For equilibrium concentrations, solve

equilibrium constant equations

mole balance equations

charge balance equation

water equation

with Newton-Raphson iteration

Page 17: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Example Equilibrium Problem

Equilibrium coefficient equations (17.76)

mH+,eq

mCl- ,eq

γH+,Cl- ,eq2

pHCl,s,eq=Keq T( )

mH+,eq

mSO4

2−,eqγ2H+,SO4

2−,eq3

mHSO4

−,eqγ

H+,HSO4−,eq

2 =Keq T( )

Page 18: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Example Equilibrium Problem

Mole balance equations (17.77)

CHCl(g),eq+cCl-,eq

=CHCl(g),t−h +cCl-,t−h

cHSO4

−,eq+c

SO42−,eq

=cHSO4

−,t−h+c

SO42−,t−h

(17.78)

Page 19: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Example Equilibrium ProblemVapor pressure as a function of mole concentration (17.79)

Charge balance equation (17.80)

Molality as a function of mole concentration

pHCl,s,eq=CHCl(g),s,eqR*T

mCl-,eq

=cCl- ,eq

cw,eqmv

cCl−,eq

+cHSO4

−,eq+2c

SO42−,eq

=cH+,eq

Page 20: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Example Equilibrium ProblemWater equation (17.81)

Hypothetical mole concentration constraints (17.82)

cw,eq =1mv

cH+,Cl- ,m

mH+,Cl- ,a

+cH+,HSO4

−,m

mH+,HSO4

−,a

+c2H+,SO4

2−,m

m2H+,SO4

2−,a

⎜ ⎜ ⎜

⎟ ⎟ ⎟

cH+,eq

=cH+,Cl-,m

+cH+,HSO4

−,m+2c

2H+,SO42−,m

cCl−,eq

=cH+,Cl-,m

cHSO4

−,eq=c

H+,HSO4−,m

cSO4

2−,eq=c

2H+,SO42−,m

Page 21: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Mass-Flux Iterative MethodSolve each equation iteratively and iterate over all equations

Initialize species concentrations so that charge is conserved

No intelligent first guess required

Solution mass and charge conserving and always converges

Example solution for one equilibrium equation

Equilibrium equation and coefficient relation

νDD+νEE +... νAA +νBB+...

A{ }νA B{ }νB ...

D{ }νD E{ }νE ...=Keq T( )

Page 22: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Mass-Flux Iterative Method1) Calculate smallest ratio of mole concentration to moles in

denominator and numerator, respectively (17.83)

2) Initialize two parameters

Qd =minCD,0νD

,CE,0νE

⎝ ⎜

⎠ ⎟

Qn =mincA,0νA

,cB,0νB

⎝ ⎜

⎠ ⎟

z1 =0.5(Qd +Qn) Δx1=Qd −z1

Page 23: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Mass-Flux Iterative MethodAdd mass flux factor (x) to mole concentrations (17.84)

3) Compare ratio of activities to equilibrium coefficient (17.85)

cA,l+1 =cA,l +νAΔxl cB,l+1 =cB,l +νBΔxl

CD,l+1=CD,l −νDΔxl CE,l +1 =CE,l −νEΔxl

F =mA,l+1

νA mB,l +1νB γAB,l+1

νA+νB

pD,l+1νD pE,l+1

νE

1Keq T( )

Page 24: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Mass-Flux Iterative Method4) Cut z in half

5) Check convergence (17.86)

Return to (17.84) until convergence occurs

zl+1 =0.5zl

F =

>1 → Δxl +1=−zl +1<1 → Δxl +1=+zl +1=1 → convergence

⎨ ⎪

⎩ ⎪

Page 25: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Analytical Equilibrium Iteration MethodSolve most equations analytically but iterate over all equations

Reactions of the form DA

Solve the equilibrium equation (17.87)

Solution for change in concentration (17.88)

Final concentrations

cA,ccD,c

=cA,0+ΔxfincD,0 −Δxfin

=Kr

Δxfin=cD,0Kr −cA,0

1+Kr

cA,c =cA,0+Δxfin cD,c =cD,0 −Δxfin

Page 26: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Analytical Equilibrium Iteration Method

Solve the equilibrium equation (17.89)

Reactions of the form D+EA+B

Solution for change in concentration (17.90)

cA,ccB,ccD,ccE,c

=cA,0 +Δxfin( ) cB,0 +Δxfin( )

cD,0 −Δxfin( ) cE,0−Δxfin( )=Kr

Δxfin=

−cA,0 −cB,0 −cD,0Kr −cE,0Kr

+cA,0 +cB,0 +cD,0Kr +cE,0Kr( )

2

−41−Kr( ) cA,0cB,0−cD,0cE,0( )

2 1−Kr( )

Page 27: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Analytical Equilibrium Iteration Method

Final concentrations

cA,c =cA,0+Δxfin

cB,c =cB,0 +Δxfin

cD,c =cD,0 −Δxfin

cE,c =cE,0 −Δxfin

Page 28: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Analytical Equilibrium Iteration Method

Check if solid can form (17.91)

Reactions of the form D(s)2A+B

If so, solve the equilibrium equation (17.92)

cA,0 +2cD,0( )2

cB,0+2cD,0( )>Kr

cA,c2 cB,c = cA,0 +2Δxfin( )

2cB,0 +Δxfin( )=Kr

Page 29: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Analytical Equilibrium Iteration MethodIterative Newton-Raphson procedure (17.93)

fn x( ) =Δxfin,n3 +qΔxfin,n

2 +rΔxfin,n +s =0

′ f x( ) =3Δxfin,n2 +2qxfin,n +r

q =cA,0 +cB,0

r =cA,0cB,0+0.25cA,02

s =cA,02 cB,0−Kr

Δxfin,n+1=Δxfin,n −fn x( )′ f n x( )

Page 30: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Analytical Equilibrium Iteration Method

Final concentrations

cA,c =cA,0+2Δxfin

cB,c =cB,0 +Δxfin

cD,c =cD,0 −Δxfin

Page 31: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Equilibrium Solver Results

Fig. 17.4

Aerosol composition versus NaCl concentration when the relative humidity was 90%. Other initial conditions were H2SO4(aq) = 10 g m-3, HCl(g) = 0 g m-3, NH3(g) = 10 g m-3, HNO3(g) = 30 g m-3, and T = 298 K.

0

5

10

15

20

25

30

0 5 10 15 20 25 30

Concentration (

g m

-3

)

NO

3

-

H

2

( ) 0.1O aq x

SO

4

2-

NH

4

+

(NaCl concentration g m

-3

)

Cl

-

Con

cent

rati

on (g

m-3)

Page 32: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Equilibrium Solver Results

Fig. 17.5

Aerosol composition versus relative humidity. Initial conditions were H2SO4(aq) = 10 g m-3, HCl(g) = 0 g m-3, NH3(g) = 10 g m-3, HNO3(g) = 30 g m-3, and T = 298 K.

0

5

10

15

20

25

0 20 40 60 80 100

Concentration (

g m

-3

)

NH

4

NO

3

( )s

NO

3

-

( )Relative humidity percent

SO

4

2-

NH

4

+

H

2

( ) 0.1O aq x

(NH

4

)

2

SO

4

( )s

Con

cent

rati

on (g

m-3)

Page 33: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Dissolutional GrowthSaturation vapor pressure of gas q over particle size i (17.95)

Saturation vapor pressure as function of gas mole concentration (17.96)

Molality as function of particle mole concentration (17.97)

pq,s,i =mq,iHq

pq,s,i =Cq,s,i R*T

mq,i =cq,i

mvcw,i

Page 34: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Dissolutional GrowthSubstitute (17.95) and (17.97) into (17.96) (17.98)

where (17.99)

Cq,s,i =pq,s,i

R*T=

mq,i

R*THq=

cq,i

mvcw,i R*THq

=cq,i

′ H q,i

′ H q,i =mvcw,i R*THq

Page 35: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Dissolutional GrowthCondensational growth equations (16.67)

(16.68)

dcq,i,tdt

=kq,i,t−h Cq,t − ′ S q,i,t−hCq,s,i,t−h( )

dCq,tdt

=− kq,i,t−h Cq,t − ′ S q,i,t−hCq,s,i,t( )[ ]i=1

NB

Page 36: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Dissolutional GrowthSubstitute (17.98)

--> Dissolutional growth equations (17.100)

(17.101)

dcq,i,tdt

=kq,i,t−h Cq,t − ′ S q,i,t−hcq,i,t′ H q,i,t−h

⎝ ⎜ ⎜

⎠ ⎟ ⎟

dCq,tdt

=− kq,i,t−h Cq,t − ′ S q,i,t−hcq,i,t′ H q,i,t−h

⎝ ⎜ ⎜

⎠ ⎟ ⎟

⎣ ⎢ ⎢

⎦ ⎥ ⎥ i=1

NB

Page 37: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Analytical Predictor of DissolutionIntegrate (17.100) for final aerosol concentration (17.102)

Mole balance equation (17.103)

Substitute (17.102) into (17.103) (17.104)

cq,i,t =′ H q,i,t−hCq,t

′ S q,i,t−h+ cq,i,t−h−

′ H q,i,t−hCq,t′ S q,i,t−h

⎝ ⎜ ⎜

⎠ ⎟ ⎟ exp−

h ′ S q,i,t−hkq,i,t−h′ H q,i,t−h

⎝ ⎜ ⎜

⎠ ⎟ ⎟

Cq,t + cq,i,ti=1

NB

∑ =Cq,t−h+ cq,i,t−hi =1

NB

Cq,t =

Cq,t−h + cq,i,t−h 1−exp−h ′ S q,i,t−hkq,i,t−h

′ H q,i,t−h

⎝ ⎜ ⎜

⎠ ⎟ ⎟

⎣ ⎢ ⎢

⎦ ⎥ ⎥

⎧ ⎨ ⎪

⎩ ⎪

⎫ ⎬ ⎪

⎭ ⎪ i=1

NB

1+′ H q,i,t−h′ S i,q,t−h

1−exp −h ′ S q,i,t−hkq,i,t−h

′ H q,i,t−h

⎝ ⎜ ⎜

⎠ ⎟ ⎟

⎣ ⎢ ⎢

⎦ ⎥ ⎥

⎧ ⎨ ⎪

⎩ ⎪

⎫ ⎬ ⎪

⎭ ⎪ i=1

NB

Page 38: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Growth During DissociationGrowth equation for hydrochloric acid (17.105)

Total dissolved chlorine (17.106)

Find saturation mole concentration from equilibrium expressions(17.107) HClHCl(aq)

(17.108) HCl(aq)H++Cl-

dcCl,i,tdt

=kHCl,i,t−h CHCl,t − ′ S HCl,i,t−hCHCl,s,i,t( )

cCl,i,t =cHCl aq( ),i,t +cCl-,i,t

Page 39: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Growth During DissociationEquilibrium coefficient relations (17.107)

(17.108)

Equilibrium coefficient relations in terms of mole concentration (17.109)

(17.110)

mHCl aq( ),i

pHCl,s,i=HHCl

molkg atm

mH+,imCl-,iγi,H+ Cl-2

mHCl aq( ),i=KHCl

molkg

CHCl,s,i =cCl,i′ K HCl,i

′ K HCl,i = HHCl 1+KHCl mvcw,i( )

2R*T

cH+,iγi,H+ Cl-2

⎢ ⎢ ⎢

⎥ ⎥ ⎥

Page 40: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Dissolution of Acids/BasesSubstitute saturation mole concentration into growth equation (17.111)

Mole balance equation (17.112)

dcCl,i,tdt

=kHCl,i,t−h CHCl,t − ′ S HCl,i,t−hcCl,i,t′ K HCl,i,t−h

⎝ ⎜

⎠ ⎟

CHCl,t + cCl,i,ti =1

NB

∑ =CHCl,t−h + cCl,i,t−hi=1

NB

Page 41: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Dissolution for Dissociating SpeciesIntegrate (17.111) for final aerosol concentration (17.113)

Substitute (17.113) into (17.112) (17.114)

cCl,i,t =′ K HCl,i,t−hCHCl,t

′ S Cl- ,i,t−h

+ cCl,i,t−h −′ K HCl,i,t−hCHCl,t

′ S HCl,i,t−h

⎝ ⎜

⎠ ⎟ exp−

hkHCl,i,t−h ′ S HCl,i,t−h′ K HCl,i,t−h

⎝ ⎜

⎠ ⎟

CHCl,t =

CHCl,t−h + cCl,i,t−h 1−exp−hkHCl,i,t−h ′ S HCl,i,t−h

′ K HCl,i,t−h

⎝ ⎜

⎠ ⎟

⎣ ⎢ ⎢

⎦ ⎥ ⎥

⎧ ⎨ ⎪

⎩ ⎪

⎫ ⎬ ⎪

⎭ ⎪ i=1

NB

1+′ K HCl,i,t−h′ S HCl,i,t−h

1−exp−hkHCl,i,t−h ′ S HCl,i,t−h

′ K HCl,i,t−h

⎝ ⎜

⎠ ⎟

⎣ ⎢ ⎢

⎦ ⎥ ⎥

⎧ ⎨ ⎪

⎩ ⎪

⎫ ⎬ ⎪

⎭ ⎪ i=1

NB

Page 42: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Solve for Ammonia/AmmoniumCharge balance equation (17.115)

where (17.116)

Mole balance equation (17.117)

cNH4+,i,t +cH+,i,t +c±,i,t =0

c±,i,t =−cNO3-,i,t −cCl-,i,t−cHSO4

- ,i,t −2cSO42- ,i,t + z

q∑ cq,i,t−h

CHCl,t =CNH3,t + cNH3 aq( ),i,t +cNH4+,i,t( )

i=1

NB

=CNH3,t−h+ cNH3 aq( ),i,t−h +cNH4+,i,t−h( )

i =1

NB

∑ =Ctot

Page 43: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Solve for Ammonia/AmmoniumEquilibrium expressions (17.118) NH3(g)NH3(aq)

(17.119) NH3(aq)+H+NH4+

Equilibrium coefficient expressions (17.118)

(17.119)

mNH3 aq( ),i

pNH3

=HNH3 mol

kg atm

mNH4+,iγi,NH4

+

mNH3 aq( ),imH+,iγi,H+=KNH3

kgmol

Page 44: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Solve for Ammonia/AmmoniumNH4

+/H+ activity coefficient relationship (17.120)

Equilibrium coefficient relations in terms of mole concentration (17.121,2)

γi,NH4+

γi,H+=

γi,NH4+γi,NO3

γi,H+γi,NO3−

i,NH4+ NO3

−2

γi,H+ NO3

−2

=γi,NH4

+γi,Cl-

γi,H+γi,Cl-=

γi,NH4

+ Cl-2

γi,H+ Cl-2

cNH3 aq( ),i

CNH3

= ′ H NH3,imolmol ′ H NH3,i =HNH3R*Tmvcw,i

cNH4+,i

cNH3 aq( ),icH+,i= ′ K NH3,i

cm3

mol′ K NH3,i =KNH3

1mvcw,i

γi,H+

γi,NH4+

Page 45: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Solve for Ammonia/AmmoniumIon concentration in each size bin (17.124)

Substitute into mole-balance equation (17.125)

cNH4+,i,t =

−c±,i,tCNH3,t ′ H NH3,i,t−h ′ K NH3,i,t−h

CNH3,t ′ H NH3,i,t−h ′ K NH3,i,t−h +1

CNH3,t +

CNH3,t ′ H NH3,i,t−h

−c±,i,tCNH3,t ′ H NH3,i,t−h ′ K NH3,i,t−hCNH3,t ′ H NH3,i,t−h ′ K NH3,i,t−h +1

⎜ ⎜ ⎜

⎟ ⎟ ⎟ i =1

NB

∑ −Ctot=0

Page 46: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Solve for Ammonia/AmmoniumIterate for ammonia gas concentration (17.126)

where (17.128)

CNH3,t,n+1=CNH3,t,n−fn CNH3,t,n( )

′ f n CNH3,t,n( )

′ f n CNH3,t,n( ) =

1+

′ H NH3,i,t−h −c±,i,t ′ H NH3,i,t−h ′ K NH3,i,t−h

CNH3,t,n ′ H NH3,i,t−h ′ K NH3,i,t−h +1

+c±,i,tCNH3,t,n ′ H NH3,i,t−h ′ K NH3,i,t−h( )

2

CNH3,t,n ′ H NH3,i,t−h ′ K NH3,i,t−h +1( )2

⎢ ⎢ ⎢ ⎢ ⎢ ⎢

⎥ ⎥ ⎥ ⎥ ⎥ ⎥

i=1

NB

Page 47: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Simulations of Growth/Dissociation

Fig. 17.7

Initial distributions for simulation

10

-1

10

0

10

1

10

2

10

-2

10

-1

10

0

10

1

10

2

10

3

10

4

0.1 1 10

dM (

g m

-3

) / d log

10

D

p

( . dN No cm

-3

) / d log

10

D

p

(Particle diameter D

p

, )m

Soildust

( )NaCl s

.Number conc

( ) a Initial

dM (g

m-3)

/ dlo

g 10 D

pdN

(No. cm

-3) / dlog10 D

p

Page 48: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Simulations of Growth/Dissociation

0

5

10

15

20

25

30

0 2 4 6 8 10 12

Summed concentration (

g m

-3

)

( )Time from start h

H

2

0.1O x

NH

4

+

NO

3

-

Cl

-

( )S VI

( ) =5b h s

Na

+

Aerosol concentrations, summed over all sizes, during nonequilibrium growth plus internal aerosol equilibrium at RH=90 percent when h=5 s.

Sum

med

con

cent

rati

on (g

m-3)

Page 49: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Simulations of Growth/Dissociation

0

5

10

15

20

25

30

0 2 4 6 8 10 12

Summed concentration (

g m

-3

)

( )Time from start h

H

2

0.1O x

NH

4

+

NO

3

-

Cl

-

( )S VI

( ) =300c h s

Na

+

Sum

med

con

cent

rati

on (g

m-3)

Same as previous slide, but h=300 s

Page 50: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Nonequilibrium Growth of SolidsGas-solid equilibrium reactions (17.129)

NH4NO3(s)NH4(g)+HNO3(g)

Solids can form when (17.131)

NH4Cl(s)NH4(g)+HCl(g) (17.130)

(17.132)

pNH3pHNO3 >KNH4NO3

pNH3pHCl >KNH4Cl

Page 51: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Nonequilibrium Growth of Solids

Gas-solid equilibrium coefficient relation (17.133)

(17.134)

CNH3,s,tCHNO3,s,t =KNH4NO3 R*T( )−2

CNH3,s,tCHCl,s,t =KNH4Cl R*T( )−2

Page 52: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Nonequilibrium Growth of SolidsGrowth equations for gases that form solids (solids formed during

operator-split equilibrium calculation)

dcNO3−,i,t

dt=kHNO3,i,t−h CHNO3,t − ′ S HNO3,i,t−hCHNO3,s,t( )

dcCl−,i,tdt

=kHCl,i,t−h CHCl,t − ′ S HCl,i,t−hCHCl,s,t( )

Page 53: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Simulations of Solid GrowthTime-dependent aerosol concentrations, summed over all sizes, during nonequilibrium growth

plus internal aerosol equilibrium at RH=10 percent when h=5 s.

Fig. 17.8

1

10

0 2 4 6 8 10 12

Summed concentration (

g m

-3

)

( )Time from start h

NH

4

NO

3

( )s

NaNO

3

( )s

(NH

4

)

2

SO

4

( )s

Na

2

SO

4

( )s

NH

4

( )Cl s

( ) =5a h s

( )NaCl s

Sum

med

con

cent

rati

on (g

m-3)

Page 54: Presentation Slides for Chapter 17, Part 2 of Fundamentals of Atmospheric Modeling 2 nd  Edition

Simulations of Solid Growth

Fig. 17.8

1

10

0 2 4 6 8 10 12

Summed concentration (

g m

-3

)

( )Time from start h

NH

4

NO

3

( )s

NaNO

3

( )s

(NH

4

)

2

SO

4

( )s

Na

2

SO

4

( )s

NH

4

( )Cl s

( ) =300b h s

( )NaCl s

Same as previous slide, but h=300 sS

umm

ed c

once

ntra

tion

(g

m-3)