Mass Transfer in Helical Bank of Tubes-Subroutine HCOIL

HCOIL is a FORTRAN IV code suitable for incorporation into plate-out codes based on the mass transfer/heat transfer analogy in heat exchangers. It calculates the mass transfer coefficient in cross flow for a bank of multistart helical tubes with uniform inclinations and uniform longitudinal pitches. It is also applicable to single coils. Predictions of caesium plate-out made by using the code are compared with the Cs-137 profile found in a Dragon primary heat exchanger. The predicted masstransfer is about 70% of that found. This discrepancy (of 30%) is small by the normal standards of accuracy obtained in plate-out measurements. It is tentatively assigned to roughness effects which are not taken into account in the theory. The agreement is regarded as sufficiently accurate for present use, though further experimental and theoretical work would be desirable. (author)