Carbon Dioxide-Lubricant Two-Phase Flow Patterns in Small Horizontal Wetted Wall Channels: The Effects of Refrigerant/lubricant Thermophysical Properties

Abstract

163 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009.This research developed measurement capabilities for measuring the solubility, miscibility, liquid density, liquid viscosity, and interfacial tension of lubricant-refrigerant mixtures. For the first time, interfacial tension measurements for refrigerant-lubricant mixtures over the range of concentrations from neat lubricant to pure refrigerant have been measured and published. The research has also lead to the development of a new prediction and modeling method for liquid viscosity and extends the historic lubricant only mixing rules to systems of lubricants with dissolved liquefied gases. A high-speed, high-pressure (< 100 bar, 1500 psia) video system has been constructed to capture the two-phase flow patterns of CO2 flows near the critical point with and without coexisting lubricant inside 0.5 mm tubes. A new flow map based on the thermophysical properties of the flowing fluid has been developed to account for the viscous and interfacial tensions effects on two-phase flows in channels below the criteria for interfacial tension affected flows.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD