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Computer program for computing the properties of seventeen fluids
Computer program for computing the properties of seventeen fluids* J.A. Brennan, D.G. Friendt, V.D. Arp and R.D. McCarty Chemical Engineering and Thermophysics Divisions, National Institute of Standards and Technology, Boulder, CO 80803-3228, USA Modifications and additions to the MIPROPS computer program for calculating the thermophysical properties of 17 fluids are described. These changes include adding new fluids, new properties and a new user interface to the program; the new program will be available from the Standard Reference Data Program of the National Institute of Standards and Technology. The new program allows the user to select the input and output parameters and the units to be displayed for each parameter.
Keywords: computer program; thermal properties; cryogenic liquids
For many years the Standard Reference Data Program (SRDP) of the National Institute of Standards and Technology (NIST) has distributed computer programs and computer databases. One such program is called MIPROPS or Standard Reference Database 12. The original program was developed by McCarty and is described in NBS Technical Note 1097 ~. The program MIPROPS uses 32-term modified B e n e d i c t - W e b b Rubin (MBWR) equations of state, plus equations for the ideal gas specific heat, the vapour pressure as a function of temperature, the melting pressure as a function of temperature, saturated liquid and vapour densities as functions of temperature and viscosity and thermal conductivity as functions of density and temperature (viscosity and thermal conductivity are not available for all fluids). About 90 numerical constants have been defined for each fluid. The evaluation of these 90 constants, from published data for the thermophysical properties of the fluid, involved extensive weighted least-squares fitting combined with careful error analysis. The program was designed to run on desktop computers and, in its original form, the user could input any two of pressure, temperature and density in the singlephase region and either pressure or temperature for properties of the saturated liquid or vapour. Outputs from the original program are pressure, temperature, density, internal energy, enthalpy, entropy, specific heat at con*Paper presented at the 1991 Space Cryogenics Workshop, 1 8 - 20 June 1991, Cleveland, OH, USA. This work was partially sponsored by NASA Lewis Research Center under contract number C-32009-K. Contribution of the National Institute of Standards and Technology; not subject to copyright in the United States of America. tTo whom correspondence should be addressed. O011 - 2 2 7 5 / 9 2 / 0 2 0 2 1 2 - 0 3 © 1992 B u t t e r w o r t h - Heinemann Ltd
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stant volume, specific heat at constant pressure, velocity of sound and, usually, viscosity, thermal conductivity and dielectric constant. The user has to globally choose either metric or English units for the input and output. There was no provision for changing the input or the output parameters or the number of significant digits displayed. The original MIPROPS program calculated properties for the following eleven fluids: argon, ethane, ethylene, hydrogen, iso- and n-butane, methane, nitrogen, nitrogen trifluoride, oxygen and propane. A separate helium program was distributed in the same database and functioned similarly. References to the source properties data for these fluids are given in Reference 1.
Program modifications In the intervening years, several modifications have been made to the MIPROPS program. The number of fluids has been increased to 17, some additional properties were added to the fluids that were deficient and a new user interface has been added. References to the source properties data for these additional fluids and properties will be given in a pending publication by Friend and McCarty 2. Some properties that have been added to the program do not have adequate experimental data to define properly the correlating functions (the thermal conductivity of hydrogen is one example). The correlations were determined by using the best available data in order to make the program as useful as possible. There is, however, a critical need for additional experimental data to verify and/or extend the range of some of the computed properties. Fluids added to the MIPROPS program are carbon
Computing the properties of fluids: J.A. Brennan et al. dioxide, carbon monoxide, deuterium, helium, normal hydrogen and xenon. The helium correlations which have been added to the MIPROPS program are not as extensive as in a separate program called HEPROPS that will also be available from SRDP. If helium properties of the highest accuracy are desired, it is recommended that the new HEPROPS program be used. That program covers the temperature range from 0.8 to 1500 K, which includes both the superfluid and normal fluid regions. A description of the helium program is given by Arp et al. in NIST Technical Note 1334 (Revised) 3. The most recent modifications to the MIPROPS program have been the addition of viscosity and thermal conductivity correlations for parahydrogen and the addition of lthe fluids normal hydrogen and xenon. From a user's point of view another recent modification, the interface, has considerably increased the utility of the program. In the original version of MIPROPS, units for all quantities were user selectable, on a global basis, in either metric or English units. In the modified version, the user has the option of selecting the units for each property individually from a list of three to five choices.
when properties of both saturated liquid and saturated vapour are desired. For the selection SATURATION, the output properties are given on two consecutive lines of the output. If only one set of saturation values is desired, then the more restrictive SATL (liquid only) or SATV (vapour only) can be specified.
Output parameters Output in the modified program is selectable by the user from 23 possible parameters. The original program output as many as 12 parameters, when available, but they were always the same and had a fixed number of displayed digits. The modified version will display a maximum of seven properties at a time, but the seven can be selected by the user and are displayed with four significant digits. If five significant digits are desired, the display must be reduced to six or fewer properties. The output is written to the screen and also to a file called MIPROPS.DAT. The 23 choices of output properties which can be displayed are given in Table 2.
Using the modified program Input parameters In the older program, the user was required to input any two of the three variables pressure, temperature and density; the program would calculate and display all output parameters. The new version requires an input of two parameters from the 12 shown in Table 1. The entries in Table i are not intended to indicate pairing, and not all pairs are valid. If an invalid pair is selected, an error message is printed and the user is requested to name a different quantity to specify the thermodynamic state. The abbreviated designations within the brackets in Table i are the minimum required input for selection of parameters. In this program, QUALITY is the mass fraction in the vapour phase of a two-phase mixture, MELT is the melting line and SATURATION is used
Table 1
Permissible input parameters
PRESSURE [PRES] DENSITY [DENS] ENTHALPY [ENTH] ENERGY [ENER] MELT [MELT] SATURATED LIQUID [SATL]
Table 2
TEMPERATURE [TEMPI VOLUME [VOLU] ENTROPY [ENTR] QUALITY [QUAL] SATURATION [SAT] SATURATED VAPOR [SATV]
A user's guide is supplied when the program is obtained from SRDP. In this section, we shall briefly review some of the highlights of the new version of MIPROPS. Help is available by inputting a question mark, ?, in response to many of the interactive queries. Properties may be calculated for state points defined by interactive keyboard input or for points tabulated in a file specified by the user. Choices for the units of both input and output properties can be selected by the user. The several default groupings of units are given in Table 3. The option 5 allows separate choices of units for each column of output; as an example, the pressure may be specified in kilopascals, megapascals, bars, atmospheres or pounds per square inch. Table 4 lists the fluids for which correlations are provided in the new MIPROPS package. Output tables may be generated by specifying initial, final and incremental values for the second input property; the first input property will be fixed for these calculations. When the program is terminated, all the output is saved to the file MIPROPS.DAT. If this file is to be saved, it must either be renamed or moved, because it will be overwritten when the program is run again. The selection of output columns, the units for input and output and the last fluid specified are saved to a file called MIPROPS.LBL. When the program is restarted, all these selections are available as default.
Permissible output properties
PRESSURE VOLUME ENERGY LATENT HEAT GAMMA a COMPRESSIBILITY CONDUCTIVITY DIFFUSIVITY
TEMPERATURE ENTHALPY QUALITY Cp EXPANSIVITY VELOCITY OF SOUND VISCOSITY DIELECTRIC CONSTANT - 1
DENSITY ENTROPY PV/RT Cv GRUNEISEN JT COEFFICIENT PRANDTL NUMBER
aRatio of heat capacities
Cryogenics 1992 Vol 32, No 2
2_13
Computing the properties of fluids: J.A. Brennan et al. Table 3
Choices o f units
Number
Pressure
Temperature
Density
Energy
Length
1 2 3
kPa bar atm
K K K
Jkg
m
4
psi
kg m - 3 kg m 3 mol I- 1 Ib f t - 3
5
R
1
jg-i J mol - 1 Btu Ib - 1
m m ft
User selected f o r each o u t p u t colum
Table 4
Choices of fluids
1 4 7 10 13 16
Argon Carbon dioxide a Ethane Hydrogen (normal) a Nitrogen Propane
= = = = = =
2 5 8 11 14 17
= = = = = =
Butane (iso) Carbon m o n o x i d e a Ethylene Hydrogen (para) Nitrogen trifluoride Xenon a
3 6 9 12 15 0
= = = = = =
Butane (normal) Deuterium a Helium Methane Oxygen Stop
~Fluids added in current version
Conclusion With the addition of the more flexible user interface, the new program has become a more useful tool for computing properties data for a number of fluids. The capability for the user to select both input and output parameters and their units makes the new program a significant time saver in many applications. The availability of source code will allow users to incorporate subroutines from MIPROPS into other programs to compute properties. This revised version of Standard Reference Database 12 will be available from the Standard Reference Data Program at NIST. Programs have also been developed for computing the properties of mixtures of fluids. Two such programs, DDMIX and SUPERTRAPP, are currently available from SRDP and are being updated periodically to include new fluids and capabilities. These programs can be used to compute pure fluid properties in addition to the properties of mixtures and therefore serve as alter-
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natives to the MIPROPS program for certain applications.
Acknowledgements Most of the work associated with the original MIPROPS program and the recent modifications were supported by NASA; the Standard Reference Data Program at NIST has provided some additional support.
References 1 McCarty, R.D. Interactive FORTRAN Programsfor Micro Computers to Calculate the Thermophysical Properties of Twelve Fluids (MIPROPS) National Bureau of Standards (US) Technical Note 1097 (1986) 2 Friend, D.G. and McCarty, R.D. to be published 3 Arp, V.D., MeCarty, R.D. and Friend, D.G. Thermophysical Properties of Helium-4 from 0.8 to 1500 K with Pressures to 2000 MPa National Institute of Standards and Technology Technical Note 1334 (Revised) (1991)
Keywords: computer program; thermal properties; cryogenic liquids
For many years the Standard Reference Data Program (SRDP) of the National Institute of Standards and Technology (NIST) has distributed computer programs and computer databases. One such program is called MIPROPS or Standard Reference Database 12. The original program was developed by McCarty and is described in NBS Technical Note 1097 ~. The program MIPROPS uses 32-term modified B e n e d i c t - W e b b Rubin (MBWR) equations of state, plus equations for the ideal gas specific heat, the vapour pressure as a function of temperature, the melting pressure as a function of temperature, saturated liquid and vapour densities as functions of temperature and viscosity and thermal conductivity as functions of density and temperature (viscosity and thermal conductivity are not available for all fluids). About 90 numerical constants have been defined for each fluid. The evaluation of these 90 constants, from published data for the thermophysical properties of the fluid, involved extensive weighted least-squares fitting combined with careful error analysis. The program was designed to run on desktop computers and, in its original form, the user could input any two of pressure, temperature and density in the singlephase region and either pressure or temperature for properties of the saturated liquid or vapour. Outputs from the original program are pressure, temperature, density, internal energy, enthalpy, entropy, specific heat at con*Paper presented at the 1991 Space Cryogenics Workshop, 1 8 - 20 June 1991, Cleveland, OH, USA. This work was partially sponsored by NASA Lewis Research Center under contract number C-32009-K. Contribution of the National Institute of Standards and Technology; not subject to copyright in the United States of America. tTo whom correspondence should be addressed. O011 - 2 2 7 5 / 9 2 / 0 2 0 2 1 2 - 0 3 © 1992 B u t t e r w o r t h - Heinemann Ltd
212
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stant volume, specific heat at constant pressure, velocity of sound and, usually, viscosity, thermal conductivity and dielectric constant. The user has to globally choose either metric or English units for the input and output. There was no provision for changing the input or the output parameters or the number of significant digits displayed. The original MIPROPS program calculated properties for the following eleven fluids: argon, ethane, ethylene, hydrogen, iso- and n-butane, methane, nitrogen, nitrogen trifluoride, oxygen and propane. A separate helium program was distributed in the same database and functioned similarly. References to the source properties data for these fluids are given in Reference 1.
Program modifications In the intervening years, several modifications have been made to the MIPROPS program. The number of fluids has been increased to 17, some additional properties were added to the fluids that were deficient and a new user interface has been added. References to the source properties data for these additional fluids and properties will be given in a pending publication by Friend and McCarty 2. Some properties that have been added to the program do not have adequate experimental data to define properly the correlating functions (the thermal conductivity of hydrogen is one example). The correlations were determined by using the best available data in order to make the program as useful as possible. There is, however, a critical need for additional experimental data to verify and/or extend the range of some of the computed properties. Fluids added to the MIPROPS program are carbon
Computing the properties of fluids: J.A. Brennan et al. dioxide, carbon monoxide, deuterium, helium, normal hydrogen and xenon. The helium correlations which have been added to the MIPROPS program are not as extensive as in a separate program called HEPROPS that will also be available from SRDP. If helium properties of the highest accuracy are desired, it is recommended that the new HEPROPS program be used. That program covers the temperature range from 0.8 to 1500 K, which includes both the superfluid and normal fluid regions. A description of the helium program is given by Arp et al. in NIST Technical Note 1334 (Revised) 3. The most recent modifications to the MIPROPS program have been the addition of viscosity and thermal conductivity correlations for parahydrogen and the addition of lthe fluids normal hydrogen and xenon. From a user's point of view another recent modification, the interface, has considerably increased the utility of the program. In the original version of MIPROPS, units for all quantities were user selectable, on a global basis, in either metric or English units. In the modified version, the user has the option of selecting the units for each property individually from a list of three to five choices.
when properties of both saturated liquid and saturated vapour are desired. For the selection SATURATION, the output properties are given on two consecutive lines of the output. If only one set of saturation values is desired, then the more restrictive SATL (liquid only) or SATV (vapour only) can be specified.
Output parameters Output in the modified program is selectable by the user from 23 possible parameters. The original program output as many as 12 parameters, when available, but they were always the same and had a fixed number of displayed digits. The modified version will display a maximum of seven properties at a time, but the seven can be selected by the user and are displayed with four significant digits. If five significant digits are desired, the display must be reduced to six or fewer properties. The output is written to the screen and also to a file called MIPROPS.DAT. The 23 choices of output properties which can be displayed are given in Table 2.
Using the modified program Input parameters In the older program, the user was required to input any two of the three variables pressure, temperature and density; the program would calculate and display all output parameters. The new version requires an input of two parameters from the 12 shown in Table 1. The entries in Table i are not intended to indicate pairing, and not all pairs are valid. If an invalid pair is selected, an error message is printed and the user is requested to name a different quantity to specify the thermodynamic state. The abbreviated designations within the brackets in Table i are the minimum required input for selection of parameters. In this program, QUALITY is the mass fraction in the vapour phase of a two-phase mixture, MELT is the melting line and SATURATION is used
Table 1
Permissible input parameters
PRESSURE [PRES] DENSITY [DENS] ENTHALPY [ENTH] ENERGY [ENER] MELT [MELT] SATURATED LIQUID [SATL]
Table 2
TEMPERATURE [TEMPI VOLUME [VOLU] ENTROPY [ENTR] QUALITY [QUAL] SATURATION [SAT] SATURATED VAPOR [SATV]
A user's guide is supplied when the program is obtained from SRDP. In this section, we shall briefly review some of the highlights of the new version of MIPROPS. Help is available by inputting a question mark, ?, in response to many of the interactive queries. Properties may be calculated for state points defined by interactive keyboard input or for points tabulated in a file specified by the user. Choices for the units of both input and output properties can be selected by the user. The several default groupings of units are given in Table 3. The option 5 allows separate choices of units for each column of output; as an example, the pressure may be specified in kilopascals, megapascals, bars, atmospheres or pounds per square inch. Table 4 lists the fluids for which correlations are provided in the new MIPROPS package. Output tables may be generated by specifying initial, final and incremental values for the second input property; the first input property will be fixed for these calculations. When the program is terminated, all the output is saved to the file MIPROPS.DAT. If this file is to be saved, it must either be renamed or moved, because it will be overwritten when the program is run again. The selection of output columns, the units for input and output and the last fluid specified are saved to a file called MIPROPS.LBL. When the program is restarted, all these selections are available as default.
Permissible output properties
PRESSURE VOLUME ENERGY LATENT HEAT GAMMA a COMPRESSIBILITY CONDUCTIVITY DIFFUSIVITY
TEMPERATURE ENTHALPY QUALITY Cp EXPANSIVITY VELOCITY OF SOUND VISCOSITY DIELECTRIC CONSTANT - 1
DENSITY ENTROPY PV/RT Cv GRUNEISEN JT COEFFICIENT PRANDTL NUMBER
aRatio of heat capacities
Cryogenics 1992 Vol 32, No 2
2_13
Computing the properties of fluids: J.A. Brennan et al. Table 3
Choices o f units
Number
Pressure
Temperature
Density
Energy
Length
1 2 3
kPa bar atm
K K K
Jkg
m
4
psi
kg m - 3 kg m 3 mol I- 1 Ib f t - 3
5
R
1
jg-i J mol - 1 Btu Ib - 1
m m ft
User selected f o r each o u t p u t colum
Table 4
Choices of fluids
1 4 7 10 13 16
Argon Carbon dioxide a Ethane Hydrogen (normal) a Nitrogen Propane
= = = = = =
2 5 8 11 14 17
= = = = = =
Butane (iso) Carbon m o n o x i d e a Ethylene Hydrogen (para) Nitrogen trifluoride Xenon a
3 6 9 12 15 0
= = = = = =
Butane (normal) Deuterium a Helium Methane Oxygen Stop
~Fluids added in current version
Conclusion With the addition of the more flexible user interface, the new program has become a more useful tool for computing properties data for a number of fluids. The capability for the user to select both input and output parameters and their units makes the new program a significant time saver in many applications. The availability of source code will allow users to incorporate subroutines from MIPROPS into other programs to compute properties. This revised version of Standard Reference Database 12 will be available from the Standard Reference Data Program at NIST. Programs have also been developed for computing the properties of mixtures of fluids. Two such programs, DDMIX and SUPERTRAPP, are currently available from SRDP and are being updated periodically to include new fluids and capabilities. These programs can be used to compute pure fluid properties in addition to the properties of mixtures and therefore serve as alter-
214
Cryogenics 1992 Vol 32, No 2
natives to the MIPROPS program for certain applications.
Acknowledgements Most of the work associated with the original MIPROPS program and the recent modifications were supported by NASA; the Standard Reference Data Program at NIST has provided some additional support.
References 1 McCarty, R.D. Interactive FORTRAN Programsfor Micro Computers to Calculate the Thermophysical Properties of Twelve Fluids (MIPROPS) National Bureau of Standards (US) Technical Note 1097 (1986) 2 Friend, D.G. and McCarty, R.D. to be published 3 Arp, V.D., MeCarty, R.D. and Friend, D.G. Thermophysical Properties of Helium-4 from 0.8 to 1500 K with Pressures to 2000 MPa National Institute of Standards and Technology Technical Note 1334 (Revised) (1991)