ABk | m² | BC cross sectional area (at BC node boundary k) |
ANn, AMn | m² | SC cross sectional area (at SC node boundary n, mean value) |
ATWMn | m² | Surface area of a (single) tube wall along a node n |
C C0, | - - | Dimensionless constant Phase distribution parameter and its slope at α = 0 |
dHY | m | Hydraulic diameter |
f(z, t), fNn, fMn | - | General and nodal (boundary and mean) solution functions |
fLIMCA | - | Upper or lower limit of the approx. function f(z,t) |
|
| Mass flow Mass flux |
h, hP, cP = hT |
| Specific enthalpy and its partial derivatives with respect to pressure and temperature (=specific heat) |
hSW = h// − h/, h//, h/ |
| Latent heat, saturation steam and water enthalpy |
KEYBC | - | Characteristic key number for each channel (BC) within an overall design |
LFTYPE = 0, 1, 2 or 3 | - | SC with saturated water/steam mixture, sub-cooled water, superheated or supercritical steam |
LFTBE (=LFTYPE of 1-st NSC) LHEATB = 0 or = 1 | - - | LFTYPE of 1-st SC within BC Non-heated or heated wall |
LNOCCF = 0 or = 1 | - | Eventual CCF situation allowed or not allowed |
NBT = NBCA − NBCE + 1 | - | Total number of BC nodes |
NBCA = NCT + NBCE − 1, NBCE | - | BC node numbers containing BC outlet or entrance |
NCT = NCA − NCE + 1 NCA, NCE, NCT = NCA − NCE + 1 | - | Total number of SC nodes BC node number containing SC outlet and entrance and total number of SC nodes |
NSC = NSCE, NSCA | - | Characteristic number of each SC, setting NSCE = 1, 2, 3 or 4 if LFTYPE = 0, 1, 2 or 3. Then NSCA = NSCE + NSCT − 1 |
P, ΔPT = PA − PE |
| Pressure and pressure difference (in flow direction) |
QBT, QBMk | W | Total and nodal power into BC node k |
|
| Mean nodal BC power density into the fluid (=volumetric heat transfer rate) |
|
| Heat flux from (heated) wall to fluid at BC node k |
|
| Linear power along BC node k |
|
| Mean nodal SC power density into fluid (=volumetric0 heat transfer rate) |
T, t | C, s | Temperature, time |
UTW | m | Perimeter of a heated (single) tube wall |
| m3 | Mean nodal SC volume |
|
| Water velocity |
|
| Steam velocity |
| - | Steam quality (extended to single-phase flow too) |