Session: 07-01: Thermal-Hydraulics Experimental Studies - I

Paper Number: 60406

Start Time: August 4, 2021, 01:15 PM

60406 - Void Fraction Measurement and Prediction of Two-Phase Boiling Flows in a Tubular Test Section 

Void fraction is one of the most important parameters that affect two-phase flow heat transfer and pressure drop.  In this paper, a high-speed X-ray radiography system and a gamma densitometer are used to measure the void fraction of two-phase boiling flows, with water as the working fluid, in a tubular test section.  The test section is made of Incoloy 800H/HT with a length of 1,000 mm, an inner diameter of 12.95 mm, and a wall thickness of 3.05 mm.  These two instrumentation systems are installed on a traversing platform and traversed along the test section for measurements at multiple elevations.  Flow boiling and natural convection boiling experiments are performed in the tubular test section at the pressures of 20, 50, and 100 psia.  Flow visualization images are obtained for bubbly and slug flows from the X-ray radiography system. The cross-sectional averaged void fraction and radial void fraction profile are calculated from the measurements of the X-ray radiography system.  The void fraction measured by the gamma densitometer is compared with that by the X-ray radiography system. The statistical uncertainties of the void fraction measurements are qualified for these instruments. In addition to the void fraction information, the wall temperature, pressure drop, and fluid temperature are also measured in these experiments.  In addition, a Multiphase Computational Fluid Dynamics (MCFD) model has been developed using ANSYS FLUENT to calculate the void fraction, wall temperature, and pressure drop in flow boiling. The experimental results will be compared with the MCFD simulation results.

Presenting Author: Qingqing Liu University of Michigan

Authors:

Qingqing Liu University of Michigan
Julio Diaz University of Michigan
Victor Petrov University of Michigan
Adam Burak University of Michigan
Annalisa Manera University of Michigan
Joseph Kelly U.S. Nuclear Regulatory Commission
Xiaodong Sun University of Michigan