CHF_local
The function CHF_Local(P, G, X, D) returns the critical heat flux for flow boiling of water flowing through a vertical tube. The function interpolates from the database presented by Groeneveld et al. (2007) which provides tables of CHF for 8 mm diameter tubes in the parameter space of mass flux, quality, and pressure. The result is corrected for diameter using the method suggested by Groeneveld (2007):
where CHF8 mm is the critical heat flux obtained by interpolation from the table.
Inputs
P - pressure (Pa, kPa, bar, MPa, psia, or atm)
G - mass flux (kg/m^2-s or lbm/ft^2-hr)
X - thermodynamic quality (note that a negative value indicated subcooled):
where h is the enthalpy and hf and hg are the enthalpies of saturated liquid and vapor, respectively.
D - diameter (m or ft)
Output
CHF_Local - critical heat flux (W/m2 or Btu/ft^2)
Example:
$UnitSystem SI Mass J C kPa
$VarInfo CHF units=W/m^2
P=1500 [kPa]
X = 0.32 [-]
D=0.009 [m]
m_dot=0.1 [kg/s]
G=m_dot/(pi*D^2/4)
CHF=chf_local(P, G, X, D)
{Solution:
CHF=3.608E+06 [W/m^2]}
Reference:
Groeneveld, D.C., J.Q. Shan, A.Z. Vasic, L.K.H. Leung, A. Durmayaz, J. Yang, S.C. Cheng, and A. Tanase, "The 2006 CHF look-up table," Nuclear Engineering and Design, Vol. 237, pp. 1909-1922, (2007).
See also: CHF_tube