Journal
EXPERIMENTAL THERMAL AND FLUID SCIENCE
Volume 64, Issue -, Pages 152-163Publisher
ELSEVIER SCIENCE INC
DOI: 10.1016/j.expthermflusci.2015.02.011
Keywords
Flash cavitation; Converging-diverging nozzle; Refrigerant-oil mixture; Pressure drop; PIV measurements
Funding
- Petrobras
- CNPq (National Institute of Science and Technology in Cooling and Thermophysics)
Ask authors/readers for more resources
An experimental facility was constructed to study two-phase flashing flows of binary mixtures in a converging diverging nozzle (Venturi tube). The effects of mass flow rate, concentration of the volatile component in the liquid phase and inlet sub-saturation (overpressure) on the axial distribution of static pressure are discussed. A transparent test section enabled visual observation of the two-phase flow in the Venturi by means of high-speed visualization (HSV) and a quantitative assessment of the velocity field was carried out using particle image velocimetry (Ply). Experimental results generated for mixtures of R-134a (volatile component) and POE ISO 10 lubricating oil (non-volatile component) showed that the liquid phase viscosity has a significant effect on both the throat pressure drop and pressure recovery in the diverging section, with the latter being directly proportional to the refrigerant concentration in the liquid phase. Visual analysis of bubble cavitation in the converging diverging nozzle revealed that the occurrence of two-phase flow in the throat and,downstream of it was quite sensitive to changes in the conditions of the flow, which quickly evolved into a homogeneous frothy mixture when the drop in pressure at the throat exceeded a certain limit. (C) 2015 Elsevier Inc. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available