R-UNSAT

DOCUMENTATION OF R-UNSAT, A COMPUTER MODELFOR THE SIMULATION OF REACTIVE, MULTISPECIESTRANSPORT IN THE UNSATURATED ZONE

US Geological SurveyOpen File Report 97-630

Authors: MA TTHEW A. LAHVISARTHUR L. BAEHR

Graphical interface developed by VISUAL-IT, Inc.Development team: CRAIG J. JOSS

COSTI ALEXANDRU

Graphical interface development funded by NJ DEP - DSR

TABLE OF CONTENTS

GETTING STARTEDThe Windows Interface

I The Main Screen

2 Runnin~ soil Diffusion Model2.1 Enter Soil Diffusion Input Data (Analvtical)2.2 Enter Soil Diffusion Input Data (Numerical)

3 Runnin~ Diffusion [n Trench Model

ADDITIONAL FEATURESTypical VallIes for Input ParametersI-D Analytical Pipe Diffusion SolutionParameter Values for I-D Steadv State Diffusion Model

R-UNSAT DOCUMENTATIONSection I - Introduction and User's Guide

Section 2 - Transport-Model Development2.1 Derivation ofthe Governin~ Transport Equation2.2 Development of the Numerical Solutions

2.2.1 Boundary and Initial Conditions for the Numerical Solutions2.2.2 Finite-Difference Solution to Radiallv Symmetric Equations

2.3 Development of the Analytical Solutions2.3.1 Boundary and Initial Conditions for the Analytical Solutions2.3.2 One-Dimensional Analytical Solutions

2.4 Constitutive Relations2A.I.Fick's Law and its Limitations2.4.2 Diffusion-Coefficient Determination

The Windows Interface

THE WINDOWS INTERFACE

1 The Main Screen

The Windows interface is a Microsoft Excel application consisted ITom the main screen, data entry forms andextensive Visual Basic code.

The main screen (see figure 33) has the following components:The model title (item 1)The results presentation area (item 2)The results selection control (item 3)The command buttons (items 4):

DIFFUSION FROM GROUNDWATERDIFFUSION FROM SOILDIFFUSION IN TRENCHPRINTHELP

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The Windows Interface

THE WINDOWS INTERFACE

1 The Main Screen

The Windows interface is a Microsoft Excel application consisted ITom the main screen, data entry forms andextensive Visual Basic code.

The main screen (see figure 33) has the following components:The model title (item 1)The results presentation area (item 2)The results selection control (item 3)The command buttons (items 4):

DIFFUSION FROM GROUNDWATERDIFFUSION FROM SOILDIFFUSION IN TRENCHPRINTHELP

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OPTIONS

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IYn·rtr:HO~FROMSOIL

Entering Model Input Data (Analytical)

THE WINDOWS INTERFACE

2 Running Soil Diffusion Model

2.1 Entering Soil Diffusion Input Data (Analytical)

The analytical method passes over the following steps:Step 2 - Boundary and Initial Conditions (figure 35);Constituent Properties (figure 36), if the "Initial Condition Option is set to "Input File";Step 3 - Physical Properties of the Constituent (figure 37);Step 4 - Lithologic Properties (figure 38), andStep 5 - Output Parameters (figure 39).

Step 2 - Boundary and Initial Conditions

Constant Gas Conc.entration (!t Watef,Taple[mg/L1Starting Gas Concentration at Water Table [mg/L]

I ...-,~~ .." .. JI ''I. ,5e-l

Constant Gas Flux at Water Table [g/cm2-s]

I ,le-9

COf1stantGas Concentration at Surfase [mg/L]

I .3e-l

Distribution of Gas Concentration at Start

I.~_~on~~antConcingo~ai~ ~~~tart .EJ

Eff,DifEus Coef. Confining UnLtat Surf [cm2/s]

I< Prey .; Next> Cancel j[J

Figure 35. Step 2- Boundary and Initial Conditions

Constituent Properties < •

x, V Values

NQTE! Press Ctrl-Enter to step to a new X-V line

j[JFigure 36. Constituent Properties

Entering Model Input Data (Vapor Diffusion)

THE WINDOWS INTERFACE

3 Running Diffusion In Trench Model

The vapor diffusion calculation passes over the following steps:Step 1 - Flow Domain Geometry (figure 50);Step 2 - Chemical type (figure 51);Step 3 - Diffusion properties (figure 52);Step 4 - Advection properties (figure 53);Step 5 - Decay parameters (figure 54).

The results of the diffusion in trench model are displayed in a tabular format as presented in figure 55.The model parameters are entered using the folowing dialog forms:

Step 1 - 1-D Utility Conduit Geometry ,i<~,J.J31

Length of 1-D Utility Conduit

L !ooo.l

1-D Utility Conduit Cross Section Cross-Section RadiusfWidth

~... 1150

Cross-S.ection Height

I 200

Cancel

Figure 50. Step 1 - Flow Domain Geometry

Step 2 - Chemical Type

] rEJ

Predefined Chemicals

I 71432 -Benzene

Dimensionless Henry's Law Coefficient [-]

I 0.115713664587588

< Prey Cancel

Figure 51. Step 2 - Chemical type

Step 3 - Diffusion Properties' gRadi.alDiffusion Length tgZero Cgnc"

no

cancel ~ j[JFigure 52. Step 3 - Diffusion properties

Step 4 - Advection Properties 131Advection Data Options

'(."jFi~id··M·~·~·~~~~;;:;~~t~·jrJLiterature Values••... , ,Air-Phase F:ermea61lily"" ,,'

L~rav~1 (~.:' !g~-E)cm3:)_~.. ~__~MIU

roOOl.Pressure Differentiai C"Io/(cm,sec2) CJatm ·,E..f'water

I 20 .. _Distance Between Measurement"

noCalculated Advectix~ FiOw Along l-DUtility CP.Ildu .fJcm/sCifeet/s

I 2,4474261074844E-04

Figure 53. Step 4 - Advection properties

Step 5 - Decay Parameters E{

.Bioaegradation inFlow Domain [lIs]

I 0,o.00~o.g11.

Figure 54. Step 5 - Decay parameters

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VAPOR DIFFUSIONof 71432 -·Benzene, ,"" "':'c,

In a Circular (R=150cm) Conduit of 1000cm Length

F;>ropertiesat end of 1-D utility conduit,

Case 1 (GL =0) Case 2 (GL>O)

Flux [mg/m2/day] Flux [mg/m2/day] Conc.[g/cm3]

2.15223E-02 2.12814E-02 1.00641E-10

6.90984E-01 6.90923E-01 3.26743E-09

2.20974E-02 2.18519E-02 1.03339E·10

7.09864E-01 7.09864E-01 3.35700E-09

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MAIN SCREEN

CONCENTRATIONOUTPUT,UNITS SELECTOR

RUN DIFFUSION

IN TRENCH

"II With biodegradation & surrounding diffu~ionI· No biodegradation & surrounding aiffusion

With biodegradation & no surrounding diffusion

No biodegradation & no surrounding diffusion

"I~~ Interface /Flowchart /.Jfl SimulationData / CP Database !JfJSii£[J Output Locations ~ Tre~~~.D!!!~~i~~l,~~~s~n Data IJJ.

Geometric parameters that need to be sp ecified by user:

L - Length 0 f domain in [em]

o - circumference of conduit [em]

A - Cro ss-sectional area of conduit [cm~

3. Chemical Parameters

Compounds of interest that need to be specifi ed by user:

Chemical

Temperature ofchemical in conduit

H - Dimensionless Henry's Law- Coefficient (see Baehr et al. WRR 35(1) P 127-136 Jan.

1999 Table 3 below for compilation ofm<!iorVOC compounds)

T abJe 3. Valuos of H t}.., ~ HenVs Uav Coe:fI'kil!n:t. for SeIo£tol VoJa:lile0r.!:aDc am..ounds ••• a Function ofT emoeJ.-&ttm!!

"Or:1nOr:1 "or::nor:?<'r:'>["J0r:

n-etlwl. tert-butyl etffir (MTI3E)

O.lJ)430.C0590.01090.01690.02590.0391

mphtlWene

NANANANA0.0174NA

trichloron-eihane (chlorofOrn\)

0.a5420.07130.09280.11970.15310.1942

1,1-dich1oroetban:.

0.07540.10180.13510.18010.23590.::053

[be1TZ.>2ne

0.09320.11640.14410.17710.21600.2618

o-xylene

0.10180.12410.15020.18060.21570.2560

ethyfue1TZ.>2ne

0.11160.14730.19240.24900.31940.4052toro.ene

0.12890.15700.18990.22810.27220.3229

m- ani p-xylene

0.14890.18060.21750.26.)20.30940.3656

cis- 1,2-dich1oroetffine

NANANANA0.::059NAtrichloroethylene (1CE)

0.19440.23860.29070.35160.42260.5046ch1o:rotretban:.

NANANA0.3900...• n

tebach1oroe tlwlene (PCE)0.32860.40500.49530.60140.72540.8692

1,1,1- bich1oroetban:. (1CA)

0.35790.430 10.51340.60900.71810.8419

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