Manual DICOM

7/24/2019 Manual DICOM

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USER MANUAL

DICOM V5.3

Contents1 INTRODUCTION ..................................................................................................................... 2

2 INPUT DATA ........................................................................................................................... 2

2.1 FUEL DATA. .................................................................................................................... 3

2.2 STEADY .......................................................................................................................... 3

2.2.1 General .................................................................................................................. 3

2.2.2 Numerics ............................................................................................................... 42.2.3 Morphology ........................................................................................................... 5

2.2.4 INJECTION RATE .................................................................................................... 6

2.2.5 MIXING LAW .......................................................................................................... 8

2.2.6 Example ............................................................................................................... 10

2.3 TRANSIENT .................................................................................................................. 11

2.3.1 General ................................................................................................................ 11

2.3.2 Numerics ............................................................................................................. 11

2.3.3 Discretization ....................................................................................................... 12

2.3.4 Morphology ......................................................................................................... 14

2.3.5 Injection rate. ...................................................................................................... 15

2.3.6 Mixing law ........................................................................................................... 18

2.3.7 Ejemplo ................................................................................................................ 20

3 OUTPUT DATA ..................................................................................................................... 21

3.1.1 Relst.dat .............................................................................................................. 21

3.1.2 Integ.dat .............................................................................................................. 22

3.2 STEADY ........................................................................................................................ 23

3.2.1 Estacionario.dat ................................................................................................... 23

3.3 TRANSIENT .................................................................................................................. 25

3.3.1 Temp1.dat ........................................................................................................... 26

3.3.2 Temp2.dat ........................................................................................................... 27

3.3.3 Dat.dat ................................................................................................................. 28


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1 INTRODUCTION

The developed model possesses a main screen to enter input data. All theresults, with fuels characteristics are written in a file.dat. This type of file allows theutilization of different software like Excel or Grapher to plot the data.

In the next chapter, we will explain more accurately the parameters needed tocreate a test model and how to enter them in the software. And in the third and lastchapter, we will explain all the output data and the structure of output files.

2 INPUT DATA

In the next paragraph we will explain all the input interfaces screens and thedata and the corresponding data,which can be as well entered by the keyboard or witha text file. But, we have to distinguish the two cases (steady and transient) in the dataintroduction because its a different data processing routine.

Nevertheless, the input interface is similar in the both cases, sharing a lot ofdata. In the both cases, there are three buttons on the right of the screen which are:

- Open: allows opening input data of a previous test which is kept on a text file.- Save: allows saving test results in a text file.- Start: starts the calculation.

Figure I.1. Interface of information of DICOM's entry, 'GENERAL' tab.


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2.1 FUEL DATA

In this new version it is possible to use different fuels, to choose them we have

to open directly the .exe corresponding to the fuel that we want use. Five fuels areproposed:

DICOM_v53_C7H16.exe: n-heptane

DICOM_v53_C10H22.exe: decane

DICOM_v53_C12H26.exe: dodecane

DICOM_v53_C16H36.exe: hexadecane

DICOM_v53_DIESEL.exe: diesel

All data which characterizes each fuel is already in the program.

2.2 STEADY

The steady test studies one case in which, injection rate and chamberproperties are constants. Therefore, there will not be any saved files for injection rate,density or pressure in function of the time.But all this information will interfere directlyfrom the interface of entry.

Another of the main differences will be explained hereinafter in the results ofexit, since this one does not possess temporary files.The execution, as the user will be able to see, will be faster than the transient case, inwhich the conditions change constantly.

2.2.1 General

The first tag allows selecting if the model is transient or steady. The only field onthis screen is the path where the data will be saved:

- Directory of outp ut Fi les: In this field we have to indicate the address in which theprogram will write the results. Moreover, there is a button, whose the name isBrowse, which allows to search in the folders.


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Figure I.3. Interface of information of DICOM's entry, 'GENERAL' tab of steady model.

For the steady case it will not be necessary to provide additional information.

2.2.2 Numerics

In this tag we have to introduce parameters for discretization that are already inexit tables or calculations. These parameters are:

- Maximum length for calculat ion [m]:Define the maximum length for calculation inwhich it will come near during the study of the flame. We can choose a characteristiclength like the diameter of combustion chamber.- Increase in x of the discret izat ion dx [m]: provides the equispread (dx) in thespatial discretization of the spray. The smaller the value of dx, the longer it will take forthe whole calculation to finish.

- Mass fract ion increase for State Relat ionsh ip: Length between points in the tableof data for the steady model. We have to take into count that mass fraction data arebetween 0 and 1.


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- Mass fract ion increase for integral tables: Like the previous parameter,discretization of mass fraction but used in calculation and data storage of integralscalculated by the program.- Convergencebou ndary for i terat ive computat ion: Indicative value for calculationend, its meaning, if the difference between results of 2 successive computations is lessthan this limit value, the calculation stops.

Moreover, we can see a picture of the screen that is described with values that,by default, the program introduces.

Figure I.4. Interface of information of DICOM's entry, 'NUMERICS' tab of steady model.

2.2.3 Morphology

In the next tag there are some parameters that define the spray, like geometry, speedprofile and distribution of mass fraction.

- Veloci ty fract ion for spray bou ndary: Velocity limit at which it will be consideredthere is no spray for being too low. It constitutes a way of delimiting the jet.- Schmidt number: The Schmidt number is in the ratio of momentum diffusivity(viscosity) and mass diffusivity. The value of the Schmidt number is normally 1 but wecan change it by a number between 0 and 1.- Spr ay angl e []: In this field we have to introduce the cone angle to define the steadyspray.


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- Radial p rof i le: This parameter allows choosing one of the four profiles available(Exponential, Spalding, Hinze y Schlichting) to calculate speed and radial mass fractionfrom its values in the central axis. The exponential-Gauss profile is the more used formodeling.

Figure I.5. Interface of information of DICOM's entry, 'MORPHOLOGY' tab of steady model.

2.2.4 Injection rate

To introduce injection rate we can choose between direct input including themomentum flow and mass flow; and derived input from the mass flow.


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2.2.4.1 Direct input

- Momentum [N]: Value of momentum flow of injected fuel. To be a steady test it hasto be a constant value.

-Mass flow [kg/s]

: Constant value of mass flow of injected fuel.

- Nozzle diameter [m]: Diameter of injector hole.

Figure I.6. Interface of information of DICOM's entry, 'INJECTION RATE' and 'DIRECT

INPUT' tab of steady model.

2.2.4.2 Derived input

In this case, it will not be necessary to take in count the momentum rate but only themass flow.

- Mass flow [kg/s]: Constant value of mass flow of injected fuel.

- Inject ion Pressure increase [Pa]: Difference of pressure in the unloading, betweeninjection and chamber.


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- Veloci ty rat io Cv: Unloading coefficient of injection hole.

- Nozzle diameter [m] :Diameter of injector hole.

Figure I.7. Interface of information of DICOM's entry, 'INJECTION RATE' and 'DERIVEDINPUT' tab of steady model.

2.2.5 Mixing law

Finally, the last tag contains parameters which define the air/fuel mixture that dependon both characteristics. There are three cases to be chosen:

2.2.5.1 Isothermal spray

In this case there is not combustion or heat Exchange. This is the simplest case which

requires only:

- Air density [kg/m3]: Air density which is in the chamber before de injection.

- Fuel density [kg /m3]: Density of injected fuel.

- Stoichiom etric mass fract ion: Relation of fuel/air mass necessary to realize thecombustion in stoichiometrics conditions.


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Figure I.8. Interface of information of DICOM's entry, 'MIXING LAW' tab of steady model to an

Isothermal Spray.

2.2.5.2 Gas jet inert/reactive Spray inert/reactive

The next two cases require the same data, but the difference between both casesresides in the state of injected fuel, gas or liquid, respectively.

- Air density [kg/m3]:Air density which is in the chamber before de injection.

- Pressu re [Pa]: Pressure in the combustion chamber.

- Reactivity param eter, fLOL: This parameter can take a value between 0 and 1 todefine the mixture fraction at the distance of the lift-off length (LOL), in other words, thepoint where the flame begins. In the point where the mixture fraction is inferior at thedefined value, the spray is reactive. If we choose the value 0, the spray will be inert; on

the other hand, if we choose 1, the spray will be totally reactive. Between both cases,the spray will have an inert zone and a reactive zone.

- YN2,inf , YO2,inf [kgi/kg]: Mass fraction values of nitrogen and oxygen, respectively, inambient air in the combustion chamber before the injection.

- Fuel temperature [K]: Fuel temperature when injected into the combustion chamber.


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Figure I.9. Interface of information of DICOM's entry, 'MIXING LAW' tab of steady model for a

Gas test.

2.2.6 Example

Finally, we can see an example of a file input.txt that saves all the input data of in

interface as we have explained earlier.

Figure I.10. Example of a file input.txt of a steady test.


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2.3 TRANSIENT

The transient models give more real tests because of the variation of conditions ateach moment,because it will have to include text files in which exists temporal relationof the written variables. However, in the next paragraph we will see each tag and the

changes in comparison with steady tests.

2.3.1 General

The interface is similar to the steady case, the only difference is that it includes a fieldto input the time step to save the temporary results:

- Time interval to saving results [s]: Define time interval where the software willcreate a new result file .dat.

Figure I.11. Interface of information of DICOM's entry, 'GENERAL' tab of transient model.

2.3.2 Numerics

Most of the parameters of spray discretization, calculations and storage of variables intables are the same that the steady test:

- Maximum length for calculat ion [m]:Defines the maximum length for calculation inwhich it will come near during the study of the flame. We can choose a characteristiclength like the diameter of combustion chamber.- Maximum tim e of calculat ion [m]: Final instant of calculation of the model.- Mass fract ion increase for State Relat ionsh ip: Length between points in the tableof data for the steady model. We have into take in count that mass fraction data isbetween 0 and 1.


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- Mass fract ion increase for integral tables: Like the previous parameter,discretization of mass fraction but used in calculation and data storage of integralscalculated by the program.- Convergenceboundary for main equat ions: Indicative value for calculation end, itsmeaning, if the difference between results of 2 successive computations is less thanthis limit value, the calculation stops.- Veloci ty value when the Spray finishes in th e cel l [m/s]: Boundary value of theend of the spray, such cell takes the velocity value of the spray, it will be considered asthe last value of spray.

Figure I.12. Interface of information of DICOM's entry, 'NUMERICS' tab of transient model.

2.3.3 Discretization

In this tag, are defined temporal and spatial criteria of discretization as well as therelation between both to avoid mistakes of calculation. Moreover its not necessary to

have a very precise spatial and temporal discretization which generates an excessivenumber of calculations and take a much longer time. For that, the following parametersare defined:

First, we will choose the mode select ion which will be automatic, already optimizedinside the program or free, defined by user.


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Figure I.13. Interface of information of DICOM's entry, 'DISCRETIZATION' tab of transient

model.

- Courant Number: This constant defines the relation between spray propagation,velocity and temporal and spatial discretization.

- Spatial incr ease: Fromthe previous equation we can find the Courant Number, andafter the only parameter needed to calculate the temporal increase is the spatialincrease. We can do the inverse, for example, give the temporal increase to have thespatial increase but in both cases, in automatic or free discretization, we need onemore parameter:

-Spatial increase constant: This parameter allows modifications, independent of

mode select ion chosen, the spatial increment, multiplying the calculation per thementioned constant.


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Figure I.13. Interface of information of DICOM's entry, 'DISCRETIZATION' tab in free

discretization mode of transient model.

2.3.4 Morphology

The parameters introduced in this part are the same as in the steady case. The onlydifference between both cases is in the program of transient model which do notcontain the possibility to use different radial profiles to calculate the distribution field ofspeed and mass fraction, and it use by default an exponential profile.

- Veloci ty fract ion for spray bou ndary: Velocity limit at which it will be consideredthere is no spray for being too low. It constitutes a way of delimiting the jet.

- Schmidt number: The Schmidt number is in the ratio of momentum diffusivity(viscosity) and mass diffusivity. The value of the Schmidt number is normally 1 but wecan change it by a number between 0 and 1.

- Spr ay angl e []: In this field we have to introduce the cone angle to define the steadyspray.


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Figure I.13. Interface of information of DICOM's entry, 'MORPHOLOGY' tab of transient model.

2.3.5 Injection rate.

The only difference between introduction of injection rate in transient and steady test isthat, in transient, we can use variable injection rate along the injection. Therefore, wewill not introduce constant values in the injection rate parameters of mass flow andmomentum, but a table of these values in function of the time. To introduce thesevalues we will introduce the name and address of the file that has data.

2.3.5.1 Direct input of injection rate

- Momentum [N]: Value of momentum flow of injected fuel. To be a transient test it hasto be a table of values.

- Mass flow [kg/s]: table of values in function of the time of mass flow of injected fuel.

- Nozzle diameter [m]: Diameter of injector hole.


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Figure I.14. Interface of information of DICOM's entry, 'INJECTION RATE' and 'DIRECT

INPUT' tab of transient model.

2.3.5.2 Derived input of injection rate

In this case, it will not be necessary to take in count the momentum rate but only the

mass flow.

- Mass flow [kg/s]: table of values in function of the time of mass flow of injected fuel.

- Inject ion Pressure incr ease [Pa]: Difference of pressure in the unloading, betweeninjection and chamber.

- Veloci ty rat io Cv: Unloading coefficient of injection hole.

- Nozzle diameter [m] :Diameter of injector hole.


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Figure I.15. Interface of information of DICOM's entry, 'INJECTION RATE' and 'DERIVED

INPUT' tab of transient model.

After, we can see an example of a temporal file: mass flow rate, momentum rate,pressure and density.


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Figure I.18. Example of the file Tasa.txt incomplete.

2.3.6 Mixing law

For the mixing law too, there is changes in the parameters, like the ambient density file

(in isothermal case), or pressure inside the camber (gases cases or spray notisothermal).

2.3.6.1 Isothermal spray

In this case there is not combustion or heat Exchange. This is the simplest case whichprecise only:

- Air density [kg /m3]: Air density which is in the chamber before de injection.

- Fuel density [kg/m3]: Density of injected fuel.

- Stoichiom etric mass fract ion: Relation of fuel/air mass necessary to realize thecombustion in stoichiometric conditions.


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Figure I.17. Interface of information of DICOM's entry, 'INJECTION RATE' and 'MIXING

LAW' tab of transient model.

2.3.6.2 Gas jet inert/reactive Spray inert/reactive

The next two cases require the same data, but the difference between both casesresides in the state of injected fuel, gas or liquid, respectively.

- Air density [kg/m3]: Air density which is in the chamber before de injection.

- Pressu re [Pa]: Pressure in the combustion chamber.

- Reactivity param eter, fLOL: This parameter can take a value between 0 and 1 todefine the mixture fraction at the distance of the lift-off length (LOL), in other words, thepoint where the flame begins. In the point where the mixture fraction is inferior at thedefined value, the spray is reactive. If we choose the value 0, the spray will be inert; on

the other hand, if we choose 1, the spray will be totally reactive. Between both cases,the spray will have an inert zone and a reactive zone.

- YN2,inf , YO2,inf [kgi/kg]: Mass fraction values of nitrogen and oxygen, respectively, inambient air in the combustion chamber before the injection.

- Fuel temperature [K]: Fuel temperature when injected into the combustion chamber.

Moreover, there is a new parameter for the non isothermal cases:

-Start of com bustio n time, t_soc [s]: This parameter introduces the instant at whichthe combustion begins. As we have seen before, its not always the same the same

value as the experimental results,but there should be an ignition delay.


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An instant previous to the indicated one, although the mixture fraction is inferior at fLOLthere will be not a reactive zone in the flame. We have to avoid incompatibility in thechoice of values. For example, if we have an oxygen mass fraction null, the spray willbe inert and the other values have to be coherent: fLOL null y tSOC bigger than the finaltime of calculation.

Figure I.18. Interface of information of DICOM's entry, 'INJECTION RATE' and 'MIXINGLAW' tab of transient model.

2.3.7 Example

An entry file input.txt complete of a transient test:


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Figure I.21. Example of the file input.txt complete of a transient test.

3 OUTPUT DATA

Output files created by both types of calculations, steady and transient, are verydifferent and we will do a chapter for each one of them. All the files are written in theaddress introduced in the interface.But there are two files which are the same for steady or transient. These two files are:

relst.datand integ.dat.

3.1.1 Relst.dat

In this output file the relative results to states relations are written, temperatures,densities and mass fraction. Nevertheless, there are many changes in function of themodeled test:

- Isothermal: In this case its only the mixture fraction and density associated with agiven mixture that are calculated.- Gaseous jet: If the test is inert the mixture fraction, the density, temperature and

mass fractions of each fuel and gas associated at each mixture fraction are tabulated.If the test is reactive, all these columns double for the reactive case- Spray:Like the previous file, the program includes two columns which contain massfractions of each fuel and their liquid and vapor phase.


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Figure I.23. Example of file relst.dat incomplete of a steady test.

3.1.2 Integ.dat

The last file of the steady calculation includes the tables of integrals calculated by themodel. In these, are tabulated with the column of mixture fraction, a group of columns

variable in function of the test type:

- Isothermal: Are calculated integrals of parameters 1, 2, Sc, 1+Sc y 0, besides theintegrals of mass under relative dosage.- Gaseous jet:Are added, at the previous columns, the integrals of all of the species,that's meaning, each unburned fuel and gases which take part- Spray: Finally, to the previous integrals are added the results of the integrals of massevaporated of each fuel, liquid and vapor mass of the same one.


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Figure I.24. Example of archive integ.dat incomplete of a steady test.

Now we are going to see the specific files of both cases:

3.2 STEADY

The steady test creates three files that the program saves and names automatically:estacionario.dat, relst.dat and integ.dat.

Now, we will describe the estacionario.dat, the other two have already been describedbefore. Its important to remind that the steady generates generic results, and not forreal instants like in transient conditions, since in an stationary test the jet is supposedlystable and therefore the results would not change from a moment to other one in thecalculation. Moreover, the number of values depends on the type of test.

3.2.1 Estacionario.dat

This file has the main results of the model, in which there is the following data:

parameter unit definition

xeje m Position on the central axis, for all values its an axialposition.

ucl m/s Spray velocity on its axis.

fc l - Mixture fraction in the spray axis.

tcx s Time of the position on the spray axis.


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Rini_u, Rini_f m Representation of the cone of the initial intact zonerepresented by a radius for each position.The initial zone is defined by two aspects, the sprayvelocity (equal to the input) and mixture fraction (equal tothe unity).

R m Spray radius.

x/deq - Quotient of the axial position value and the equivalentdiameter.This value is a normalized data for other tests withdifferent conditions.

numiter - Iteration number necessaryto come to the solution in theloop of calculation.

M kg/s Mass flow which crosses each defined section by axialposition.

umed m/s Average velocity along the section.

fmed - Average mixture fraction along the section.

rho_cl kg/m3 Density on the axis.

rho_med kg/m3 Average density on the section.

rho_med_flujo kg/m3 Average density calculated on the flow.

R_x m Radius of each section in which there is a relativedosage of x.

Revap_CXHy m Radius of each section in which the spray passes fromtotally liquid to totally gaseous.There are as many columns as fuels and if the jet is not aspray the radius gives itself for the relative dosage 3.

mf kg/m Total fuel quantity that there is by length in each section

mfmix_x kg/m Total fuel quantity that there is by length in each sectionwith relative dosage richer than x.

mf_CXHymixevap kg/m Fuel quantity indicated that there are by length below thedosage of evaporation of the fuel.

ma kg/m Air quantity that there is by length in each section

S_x m Penetration curve of jet with a relative dosage of x.

Sevap_CXHy m Penetration curve of evaporation surface of the fuel.For jet no spray will be represented under the relativedosage 3.

miny kg Total mass injected up to the axial position indicated.

mfmix_x_ac kg Total mass accumulated up to the indicated sectionunder the dosage x.

mfCXHy_m ixev ap

_ac

kg Total mass accumulated up to the surface of evaporationdosage of each fuel, or by default, the relative dosage 3.

ma_ac kg Air mass accumulated up to the indicated section.

mfCXHy_s q kg/m Quantity of unburned fuel by length, except for theisothermal case.

mfCXHy_l kg/m Quantity of fuel by length, respectively liquid and vapor,for each section.

mfCXHy_s q_ac kg/m Total mass of the unburned fuel up to a section.

mf_q_ac kg/m Global mass of the burned fuel up to a section.

mfCXHy_l _ac ,m fCXHy_v _ac

kg/m Total mass accumulated of the fuel by length up to asection, liquid and vapor,respectively.


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mO2_ac,

mCO2_ac,

mH2O_ac

kg/m Total mass accumulated up to a section of gases thattake part, depends on the test conditions,so that it is possible that there is none of the three, onlyoxygen or four gases

Tcl K Temperature of jet in its axis.

Tmed K Average temperature of jet for one section.YfCXHy_c l - Massfraction of the fuel in a jet axis.

YfCXHy_v _c l,

YfCXHy_l _c l

- Mass fraction of the fuel in each phase, respectively,vapor or liquid in the central line.

YN2_cl,YO2_cl,Y

CO2_cl,YH2O_cl

- Mass fraction in the axis of each one of the gases whichtake part in the test.

Figure I.22. Example of file estacionario.dat incomplete of a steady test.

3.3 TRANSIENT

In the transient test, we have already seen that the input data could be variable, inconsequence, a study is realized with a temporal follow up which is composed by thefollowing files: Temp1.dat, Temp2.dat, relest.dat, integ.dat and dat.dat. The first twofiles are unique for each test which reference different variables in function of time indifferent columns. The integrals file and state relations file are the same as in steadycalculations, with the only difference that the calculation for both is made two times,one time before the combustion and a second at the beginning of the combustion. Andfinally, the temporal files, with interval of time specified in the first screen of input data,they gather concrete moments of the jet in studding a series of variables around itsposition in the axis.Now, we are going to see each text file:


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3.3.1 Temp1.dat

Only one file of this type is created, which gathers variables that are used in thecalculation module at each moment. These are the variables of the calculation, with acolumn of time variable:


u0 m/s Velocity of injection at the exit of the nozzle.

I0 N Momentum rate of injected jet at the exit of the nozzle.

M0 kg/s Mass flow of fuel in entry. The three previous variables are

directly connected and will be introduced as entry data.

rho_a[] kg/m

3

Ambient air density inside the chamber for each moment,

introduced via a text file.rho_f kg/m

3

Injected fuel density for each moment, introduced since a textfile.

do m Nozzle diameter, constant during all the calculation.

Ta K Air temperature.

Ts t K Temperature of stoichiometric surface.

fLOL - This parameter takes the null value (inert test) until thetime of start of combustion, after that it takes the value indicatedby the user.

fevap_CxHy - Indicates the dosage of evaporation calculated for the fuel.

Figure I.25. Example of archive temp1.txt incomplete of a transient test.


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3.3.2 Temp2.dat

Variables tabulated in this archive represent some variables at the exit of the loop ofcalculation. Are represented in function of the time:


S m Penetration value of the jet.

S_x m Penetration value of the surface with relative dosage x.

S_evap_CxHy m Penetration value of the surface of evaporation of the fuel.

S_evap_o_CxHy m Penetration value of the surface of evaporation of the fuel,calculated from the origin.

miny kg Fuel mass injected up to a given moment.ma kg Air mass accumulated in the jet up to a given moment.

mfmix_x_ac kg Fuel mass accumulated up to the moment under the relativedosage x.

mfCxHy_m ixev ap

_ac

kg Fuel mass accumulated up to the moment under the dosageof evaporation of each fuel.

LOL m Lift-off-length, distance since the exit of the nozzle until the liftoff of the flame

mfCxHy_s q_ac kg Mass of the unburned fuel accumulated up to the moment.

mf_q_ac kg Global mass of burned fuel accumulated up to the moment.

mO2_ac,

mCO2_ac,

Mh2O_ac

kg Mass of gaseous species which take part, accumulated insidethe jet up to a given moment.

mfCxHy_l ,

m fCxHy_v

kg/

m

Mass by unit of length of the fuel, in liquid or vapor, respectively

uclmax m/s Maximal velocity along the jet at every moment.

x_uclmax m Distance at which there is the maximal velocity of jet on its axis.

fc lmax - Maximum mixture fraction of the jet.

x_fclmax m Position at which there is the maximal mixture fraction of jet onits axis.


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Figure I.26. Example of archive temp2.txt incomplete of a transient test.

3.3.3 Dat.dat

The program creates files at every time interval, determined by the user to save results.

This file contains variables that are represented in function of the axis position of thejet, which define an immediate picture of jet.These variables are:


uclmax m/s Maximal velocity along the jet at every moment.

fc l - Mixture fraction in the spray axis.

I N Momentum of the jet for the defined section

Mf kg/s Mass flow of fuel in the defined section.

INT_u_XR_ant kg*m/s Integral of the velocity at the previous volume.INT_f_XR_ant kg Integral of the mixture fraction at the previous volume.

M kg/s Mass flow that crosses each defined section by axialposition.

umed m/s Average velocity along the section.

fmed - Average mixture fraction along the section.

rho_cl kg/m3 Density on the axis.

rho_med kg/m3 Average density on the section.

R m Spray radius for each defined section.

Rini

m Limit radius which defines the cone of the intact initial zone

for every radial position.R_x m Radius of each section in which there is a relative dosage


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of x.

Revap_CXHy m Radius of each section in which the spray passes fromtotally liquid to totally gaseous. There are as manycolumns as fuels and if the jet is not a spray the radiusgives itself for the relative dosage 3.

mf kg/m Total fuel quantity that there is by length in each section.

mfmix_x kg/m Total fuel quantity that there is by length in each sectionwith relative dosage richer than x.

mf_CXHymixeva

p

kg/m Fuel quantity by length under the dosage of evaporation ofthe fuel.

ma kg/m Air quantity that there is by length in each section

mfCXHy_s q kg/m Quantity of the unburned fuel by length,except for the isothermal case.

mfCXHy_l ,

m fCXHy_v

kg/m Quantity of each fuel by length, liquid and vapor,respectively

mO2,

mCO2,

mH2O

kg/mTotal mass until a section of gases that take part.Depends on the test conditions, so that it is possible thatthere is none of the three, only oxygen or four gases

Tcl K Temperature of jet in its axis.

Tmed K Average temperature of jet for one section.

YfCXHy_c l - Massfraction of each fuel in a jet axis.

YfCXHy_v _c l,

YfCXHy_l _c l

- Mass fraction of the fuel in each phase in the central line,

liquid and vapor, respectively.

YN2_cl,

YO2_cl,

YCO2_cl,

YH2O_cl

- Mass fraction in the axis for each one of the gasesthat take part at the test.


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Figure I.27. Example of file dat.dat incomplete of a transient test.

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