Experimental Two-Phase Flow Characterization of Subcooled Boiling in a Rectangular Channel

Abstract

On the efforts to provide a reliable source of experimental information on turbulent subcooled boiling ow, time resolved Particle Tracking Velocimetry (PTV) experiments were carried out using HFE-301 refrigerant ow through a vertical rectangular channel with one heated wall. Measurements were performed at liquid Reynolds numbers of 3309, 9929 and 16549 over a wall heat flux range of 0.0 to 64.0 kW=m2. From the PTV measurements, liquid two dimensional turbulence statistics are available, such as: instantaneous 2-D velocity fields, time-averaged axial and normal velocities, axial and normal turbulence intensities, and Reynolds stresses. The present results agree with previous works and provide new information due to the 2-D nature of the technique, for instance, this work shows that by increasing heat ux, the boiling bubbles influence on the liquid phase is portrayed as a persistent increase of axial velocity on regions close to the heater wall. This persistent increase on the axial velocity reaches a maximum value attributed to the terminal bubble velocity. These new observed phenomena must be considered for the development and improvement of two-phase ow turbulence models. To this end, an extensive error analysis was also performed with emphasis on the applicability of the PTV measurement technique on optically inhomogeneous flows. The error quantification exhibited negligible optically induced errors for the current conditions, making the data acquired in this work a vast and reliable source.