Unit System and Conventions
Naming Conventions
Parameter |
Read As |
p_bar |
\(p\) \([bar]\) |
alpha_w_per_m2k |
\(\alpha\) \([\frac{W}{m^2 \cdot K}]\) |
vdot_m3_per_s |
\(\dot{V}\) \([\frac{m^3}{s}]\) |
Reference State Values
For calculations of compressible media, the normal conditions following DIN 1343 are used:
Parameter |
Value |
NORMAL_PRESSURE |
1.01325 \([bar]\) |
NORMAL_TEMPERATURE |
273.15 \([K]\) |
Implemented Constants
Implemented physical constants can be found in the python module “constants.py”:
Constant |
Value |
Meaning |
GRAVITATION_CONSTANT |
9.81 \([\frac{m}{s^2}]\) |
Gravitation constant |
MOLAR_MASS_AIR |
0.02896 \([\frac{m^3}{mol}]\) |
Molar mass of air |
R_UNIVERSAL |
8.314 \([\frac{J}{K \cdot mol}]\) |
Universal gas constant |
Flow Directions
Edges between junctions are created using functions, which require a “from_junction” and a “to_junction” parameter, so the edges in the network are directed. A positive velocity value calculated for an edge is assumed to be positive if the flow direction is in alignment with the direction of the edge. Otherwise, the velocity value is negative.