NAMEatrtp - AsToRia: Thermodynamic Properties
atrtp is a binary file format to store a set of thermodynamic porperties for each node a volumetric mesh representing a medium in combustion. An atrtp file begins by a header that describes the data layout followed by a list of per node properties.
The header is made up of 2 64-bit integers. The first integer is a power of two (usually 4096) that defines the <pagesize> in bytes to which the thermodynamic properties are aligned. The remaining integer store the number of items in the list. In the following grammar, we name it <#nodes>, for "number of nodes", in reference to the mesh nodes to which these properties would be attached.
Note that by aligning the thermodynamic data to <pagesize>, and depending on the system requirements, memory mapping can be used to automatically load/unload those data on demand (see for example the POSIX C function mmap(2)).
Padding bytes follow the file header to ensure alignment of the thermodynamic properties to <pagesize>. These properties are then listed with 8 double precision floating point numbers per item (i.e. per node). The set of per node data are:
- * The pressure in Pascal
- * The temperature in Kelvin
- * The molar fraction of H20 in mol(H20)/mol(mixture)
- * The molar fraction of CO2 in mol(CO2)/mol(mixture)
- * The molar fraction of CO in mol(CO)/mol(mixture)
- * The volumic fraction of soot in m3(soot)/m3
- * The number of soot primary particules per agregate
- * The soot primary particles diameter in nm
Finally, additional padding bytes are added after the listed properties to align the overall file size to <pagesize>.
BINARY FILE FORMAT
Data are encoded with respect to the little endian bytes ordering, i.e. least significant bytes are stored first.
<atrtp> ::= <pagesize> <#nodes> <padding> <thermo-props> <padding> <pagesize> ::= INT64 <#cells> ::= INT64 <padding> ::= [ BYTE ... ] <thermo-props> ::= <thermo-prop> [ <thermo-prop ... ] <therm-prop> ::= <pressure> <temperature> <xH2O> <xCO2> <xCO> <vf-soot> <np-soot> <dp-soot> <pressure> ::= <double> # Pressure in Pa <temperature> ::= <double> # Temperature in K <xH2O> ::= <double> # Molar fraction of H2O in mol(H2O)/mol(mixture) <xCO2> ::= <double> # Molar fraction of CO2 in mol(CO2)/mol(mixture) <xCO> ::= <double> # Molar fraction of CO in mol(CO)/mol(mixture) <vf-soot> ::= <double> # Volumic fraction of soot in m^3(soot)/ m^3 <np-soot> ::= <double> # Number of primary particles per agregate <dp-soot> ::= <double> # Primary particles diameter in nm