A. Attou et L. Bolle, INTEGRAL FORMULATION OF BALANCE-EQUATIONS FOR 2-PHASE FLOW-THROUGH A SUDDEN ENLARGEMENT .1. BASIC APPROACH, Proceedings of the Institution of Mechanical Engineers. Part C, Journal of mechanical engineering science, 211(5), 1997, pp. 387-397
A general expression of irreversible losses related to two-phase flows
through a sudden enlargement is derived from basic balance equations
(mass, momentum and energy). The need to take into account void fracti
on and quality changes is emphasized for some one-fluid flows. From a
comparison with several experimental results, it is concluded that a v
oid fraction decrease downstream of the enlargement must be considered
in order to predict satisfactorily pressure variations on the basis o
f the momentum balance procedure. When expressed in the form of a frac
tion of reversible pressure recovery, dissipation losses appear to dep
end strongly on the quality. Their minimum value is observed for a lar
ger quality value when the pressure of the system is increased.