Heated Length Factor
function K_4 input SI.Length D_hyd "Hydraulic diameter of subchannel"; input SI.Length L_htd "Heated length"; input SI.Density rho_lsat "Fluid saturation density"; input SI.Density rho_vsat "Vapor saturation density"; input SIadd.NonDim x_abs "Absolute quality"; output Real K "Correction factor"; end K_4;