Experimental and numerical studies of solid-liquid multiphase flow in pipes

 
 
 
 

Experimental and numerical studies of solid-liquid multiphase flow in pipes

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Title: Experimental and numerical studies of solid-liquid multiphase flow in pipes
Author: Chen, Rong-Che
Description: A unique refractive index matched facility for studying solid-liquid multiphase flow has been developed. The refractive index matching of the solid and the liquid allows the use of non-intrusive Laser Doppler Velocimetry (LDV) to measure the solid and the liquid velocities. Silica gel particles of mean diameter 40 microns and 50% sodium iodide solution in water (refractive index ∼eq 1.4429) are used as the refractive index matched solid and liquid respectively. A two color back scatter mode LDV is used for making velocity measurements of both liquid and solid phases. Tests were conducted for solid-liquid slurry flows in a one inch diameter pipe with volumetric solid concentration levels of 5%, 15%, 25% and 30% in the Reynolds number range of 500 to 15000. The Reynolds number is based on the mean velocity of slurry, the pipe diameter and the liquid viscosity. Measurements included mapping of the solid and liquid velocities and obtaining the pressure drop data. A comparison between axial velocity profiles along the vertical and horizontal diameters associated with the observation of the height of settled solid particles on the bottom of pipe was used for demarcating flow regimes. The four flow regimes, stationary bed flow, saltation flow, heterogeneous flow and homogeneous flow, w ere identified with respect to Reynolds number. Pressure drop measurements were made by using inclined tube manometer. The comparison of friction factor with Turian's correlation shows very good agreement in the homogeneous flow regime. A signal processing technique utilizing histogram of velocity measurements made at a point and signal amplitude discrimination was successfully used for differentiating between the solid and liquid velocities. Differences between the solid and liquid velocities were observed for the saltation flow and heterogeneous flow regimes for 15% and 25% slurries. No velocity difference between solid and liquid was detected for slurries flow in the homogeneous flow regime for all solid concentrations. A numerical model based on the transport equations and empirical coefficients for interphase interactions was successfully developed for predicting flow properties of a slurry in the homogeneous flow regime for solid concentration up to 25% by volume. This numerical model provides the velocity profile for each phase, the solid concentration distribution, the turbulent kinetic energy and the dissipation rate of turbulence for homogeneous flow of slurry. The axial velocity profile compared well with the experimental data.
Permanent Link: http://rave.ohiolink.edu/etdc/view?acc_num=case1055532292
http://hdl.handle.net/2374.OX/16716
Date: 1991

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