Phase distribution and bubble velocity in two-phase slit flow

The phase distribution, the bubble velocities and the thermal expansion beh aviour of the bubbles in two-phase bubbly slit flow were examined by using high-speed cinematography. The phase distribution in (adiabatic) hashing wa ter and non flashing air/water flow is relatively homogeneous. Under all fl ow conditions the slip ratio in the one dimensional flow is less than 1.2. It can be recalculated by assuming the pressure and the friction forces on the bubble surface in equilibrium. The cavitation in a slightly subcooled l iquid occurring at a sharp edged slit inlet has a significant influence on the post-evaporation behaviour. In principle, the assumption of a homogeneo us mixture flow in thermodynamic equilibrium is validated, the deviations a re mutually neutralizing to a large extent. (C) 1999 Elsevier Science Ltd. All rights reserved.