Accession Number : ADP009036

Title :   Influence of Expansion Ratio on the Size of Recirculation Zone in Two-Phase Sudden Expansion Flows,

Corporate Author : NATIONAL TECHNICAL UNIV ATHENS (GREECE)

Personal Author(s) : Founti, M. ; Papaioannides, G.

Report Date : 23 JUL 1992

Pagination or Media Count : 6

Abstract : The paper presents measurements of the reattachment length and of the axial velocity component in a descending turbulent axisymmetric sudden expansion flow, for three expansion ratios of 1:2, 1:3 and 1:4. The measurements have been performed with a standard laser Doppler anemometer, first in the single-phase flow and then repeated for the fluid and particles in the two-phase flow cases by eliminating from the raw Doppler signals each time one of the two burst populations. For the two-phase flows the measured reattachments lengths were 6-10% shorter than for the corresponding single-phase cases. Fort particle volumetric concentrations up to 0.027, the axial mean velocities and normal stresses were not affected as the concentration was increased. (Author)

Descriptors :   *TWO PHASE FLOW, *THERMAL EXPANSION, TURBULENCE, AXIAL FLOW, CONCENTRATION(COMPOSITION), RECIRCULATION, CLOSED LOOP SYSTEMS, SPATIAL DISTRIBUTION, PHASE DISTORTION, FLOW FIELDS, REYNOLDS NUMBER, SOLID PHASES, LIQUID PHASES, VOLUMETRIC ANALYSIS, OPTICAL IMAGES, SIGNAL TO NOISE RATIO, AXISYMMETRIC FLOW, COMPARISON, EXPERIMENTAL DATA, GREECE.

Subject Categories : Fluid Mechanics
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE