Jet-A Vaporization Computer Model A Fortran Code Writte

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					 Jet-A Vaporization Computer
           Model

       A Fortran Code Written by Prof.
     Polymeropolous of Rutgers University

 Steve Summer                      International Aircraft Systems
 Project Engineer                  Fire Protection Working Group
 Federal Aviation Administration   Seattle, WA
 Fire Safety Section, AAR-422      March 12 – 13, 2002

IASFPWG – Seattle, WA                                       03-12-02
                   Acknowledgements

 Professor C. E. Polymeropolous of Rutgers
  University

 David Adkins of the Boeing Company



IASFPWG – Seattle, WA                   03-12-02
                        Introduction
 Original code was written as a means of
  modeling some flammability experiments
  being conducted at the Tech Center
                              1 Liquid
  (Summer, 1999)              Thermocouple
                                                    5 Gas Thermocouples

                                                                               2 HC Ports


                                                                             5 Wall and
                                                                              Ceiling
                                                                             Thermocouples
                            1.2 m



                                                                          0.93 m

                                                 2.2 m
                                                            Air Out
                                    Hot Air In
IASFPWG – Seattle, WA                                      Fuel                    03-12-02
                                                           Pan
                        Introduction
  This model proved a good method of predicting
   the evolution of hydrocarbons (i.e. it matched the
   experimental data).
       • Results were presented by Prof. Polymeropolous
         (10/01 Fire Safety Conference)
  Could prove to be a key tool in performing fleet
   flammability studies.
  Fortran code has been converted to a user-friendly
   Excel spreadsheet by David Adkins of Boeing.

IASFPWG – Seattle, WA                                     03-12-02
                        Previous Work
  Numerous previous investigations of free convection heat
   transfer within enclosures
       • Review papers: Catton (1978), Hoogendoon (1986), Ostrach
         (1988), etc.
       • Enclosure correlations
  Few studies of heat and mass transfer within enclosures
       • Single component fuel evaporation in a fuel tank, Kosvic et al.
         (1971)
       • Computation of single component liquid evaporation within
         cylindrical enclosures, Bunama, Karim et al. (1997, 1999)
  Computational and experimental study of Jet A
   vaporization in a test tank (Summer and Polymeropoulos,
   2000)
IASFPWG – Seattle, WA                                                03-12-02
          Physical Considerations
 3D natural convection heat and
  mass transfer within tank
    • Fuel vaporization from the
      tank floor which is          Walls and Ceiling, Ts
      completely covered with
      liquid                               Gas, Tg

    • Vapor
      condensation/vaporization
      from the tank walls and
      ceiling
  Multi-component
    vaporization and
    condensation                         Liquid, Tl
  Initial conditions are for an
    equilibrium mixture at a
IASFPWG – Seattle, WA                                      03-12-02
    given initial temperature
          Major Assumptions
  Well mixed gas and liquid phases within the
   tank
    • Uniform temperature and species concentrations
      in the gas and within the evaporating and
      condensing liquid
    • Rag ≈109, Ral ≈ 105-106
   Externally supplied uniform liquid and wall
     temperatures. Gas temperature was then
     computed from an energy balance
   Condensate layer was thin and its
     temperature equaled the wall temperature.03-12-02
IASFPWG – Seattle, WA
      Major Assumptions (cont’d)
  Mass transport at the liquid–gas interfaces
   was estimated using heat transfer
   correlations and the analogy between heat
   and mass transfer for estimating film mass
   transfer coefficients
  Low evaporating species concentrations
  Liquid Jet A composition was based on
   previous published data and and adjusted to
   reflect equilibrium vapor data
   (Polymeropoulos, 2000)
IASFPWG – Seattle, WA                       03-12-02
      Assumed Jet A Composition
                         Co mpoun d                Vo lu me ,%   Mol ecul ar    Bo il i ng   De nsi ty,
                                                                  Wei gh t     Po in t, °C    kg/m3
                         C5 p ara fi ns               0.01           72          30 9           63 0
                         C6 p ara ffi ns              0.15           86          34 1           66 4


  Based on data by
                         C7 p ara ffi ns               0.5          10 0         37 1           69 0
                         C8 p arrafi ns                0.5        11 4.2         39 1           70 0
                         C8 cycl op araffi ns          0.5        11 2.2         39 7           78 0

   Clewell, 1983, and    C8 a roma ti cs
                         C9 p ara ffi ns
                                                      0.54
                                                     2.33 3
                                                                  10 6.2
                                                                  12 8.3
                                                                                 41 2
                                                                                 41 5
                                                                                                87 0
                                                                                                72 0
                         C9 cycl op araffi ns        1.43 3       12 6.2         42 7           80 0
   adjusted to reflect   C9 a roma ti cs
                         c1 0 paraffin s
                                                     0.93 3
                                                     5.53 3
                                                                  12 0.2
                                                                  14 2.3
                                                                                 43 8
                                                                                 43 3
                                                                                                88 0
                                                                                                72 0

   for the presence of   c1 0 cycl opa ra ffi ns
                         c1 0 aromati cs
                                                     3.43 3
                                                     2.23 3
                                                                  14 0.3
                                                                  13 4.2
                                                                                 44 4
                                                                                 45 0
                                                                                                80 0
                                                                                                86 0
                         c1 1 paraffin s             8.63 3       15 6.3         46 9           74 0
   lower than C8         c1 1 cycl opa ra ffi ns
                         di cycl op araffi ns
                                                     3.23 3
                                                     3.03 3
                                                                  15 4.3
                                                                  15 2.3
                                                                                 46 9
                                                                                 47 4
                                                                                                80 0
                                                                                                89 0

   components            c1 1 aromati c
                         c1 2 paraffin s
                                                     3.53 3
                                                    10 .7 33
                                                                  14 8.2
                                                                  17 0.3
                                                                                 47 8
                                                                                 48 9
                                                                                                86 0
                                                                                                75 0
                         c1 2 cycl opa ra ffi ns     7.93 3       16 6.3         49 4           88 0
                         c1 2 aromati cs             4.53 3       16 2.3         48 9           86 0
                         c1 3 paraffin s            11 .4 33      18 4.4         50 8           76 0
                         c1 3 cycl opa ra ffi ns     8.43 3       18 2.4         49 8           80 0
                         c1 3 aromati cs             4.83 3       17 6.3         50 7           87 0
                         c1 4 paraffin s             5.83 3       19 8.4         52 7           76 0
                         c1 4 cycl opa ra ffi ns     4.33 3       19 2.4         56 3           94 0
                         c1 4 aromati cs             2.43 3       18 6.3         56 8          10 30
                         c1 5 parafi ns              1.33 3       21 2.4         54 4           77 0
                         c1 5 cycl opa ra ffi ns     0.93 3       20 6.4         57 3           90 0
                         c1 5 aromati cs             0.53 3       20 0.4         57 8           95 0
IASFPWG – Seattle, WA    c1 6 hyd ro ca rb ons       0.13 3       22 6.4         56 0        03-12-02
                                                                                                77 0
      Assumed Jet A Composition
                      25


                      20       MW: 164
        % by Volume




                      15


                      10


                       5


                       0
                           5    6   7    8   9   10   11   12     13   14   15   16

                                         Number of Carbon Atoms

IASFPWG – Seattle, WA                                                                 03-12-02
        PRINCIPAL MASS CONSERVATION AND
         PHYSICAL PROPERTY RELATIONS
             Liquid Mass Balance :
                                       d
                                         mli   Al Shi Di y fi  y gi 
                                      dt              L
                                  x p
              Henry's Law : x fi  li i
                                    p
                                                                                   
                                                                         2899      
             Modified AntoineEquation : pi  exp20.53                             
                                                                 385.15  62.3 
                                                                            Tl
                                                      
                                                                          Tbi      
                                                                                    
                                          dmgi
             Gas SpeciesMass Balance :            mei  mci  mo y gi or mo yair
                                                                            
                                            dt
                                  d mg c pgTg 
             Gas Energy Balance :                 hl Al Tl  Tg   hw Tg  Tw 
                                         dt
                                  me c pvTl  mc c pgTs  mo c pgTa or  mo c pgTa
                                                                          
             Ideal Gas, Constant Pressure(p  c) Mixture
             Fuller's Method for Gas Species DiffusionCoefficients
IASFPWG – Seattle, WA                                                                   03-12-02
 Heat/Mass Transfer Coefficients
            Horizontal Tank Surfaces

                                      0.055Gr Pr  (Hollands et al. 1975)
                                 hL
            Heat Transfer : Nu 
                                                    1/ 3

                                  k
            Mass Transfer : Shi  i  0.055GrSci 
                                 hL                   1/ 3

                                  Di
                                            g  s   g L3
                               with Gr 
                                                  2

            VerticalSurfaces
                                 hH                    1/ 3
            Heat Transfer : Nu       0.664 Re 0.5 pr         (Vertical Plate)
                                  k
                                 hH                       1/ 3
            Mass Transfer : Shi  i  0.664 Re 0.5 Sci
                                  Di

                               with Re 
                                         g T   g    Ts H   
                                                                0.5
                                                                      H
                                                       
IASFPWG – Seattle, WA                                                             03-12-02
                        User Inputs
 Equilibrium Temperature
 Final Wall and Liquid Temperatures
 Time Constants
 Mass Loading
 Tank Dimensions



IASFPWG – Seattle, WA                  03-12-02
                        Program Outputs
 Equilibrium gas & liquid
  concentrations/species fractionation
 Species fractionation as a function of time
 Ullage, wall and liquid temperatures as a
  function of time
 Ullage gas concentrations as a function of
  time
       • FAR, ppm, ppmC3H8

IASFPWG – Seattle, WA                      03-12-02
                        Fortran Program
                         Demonstration



IASFPWG – Seattle, WA                     03-12-02
    Excel Version Demonstration




IASFPWG – Seattle, WA         03-12-02
                        Sample Results




IASFPWG – Seattle, WA                    03-12-02
                        Future Work
  Provide the ability to vary liquid fuel distribution
   throughout the tank.
  Provide the ability to input temperature profiles
   for each tank surface.
  Provide the ability to track pressure changes
  Experimental validation tests will be conducted in
   the near future at the tech center.



IASFPWG – Seattle, WA                              03-12-02