This thesis describes the development of an experimental facility for testingcapillary-tube expansion devices and presents preliminary data for flow of R-134a ina non-adiabatic capillary tube. The capillary tube is the expansion device of choicein domestic refrigerators and some other refrigeration systems because of itssimplicity and low cost. However, two-phase flow phenomena in capillary tubes arecomplex. New energy efficiency requirements and the advent of the Montreal. Protocol which mandates the replacement of CFC refrigerants such as R-12 withalternatives such as HFC refrigerant R-134a, have combined to create a need formore extensive research on the flow characteristics in capill.ary tubes.A literature review reveals that little progress has been made since the 1950'sin predicting the behavior of capillary-tube flow accurately. Data for non-adiabaticoperation and for capillary tubes using R-134a are scarce. Most experimentationhas been geared toward validating specific rather than gathering data for conditionsactually seen in domestic refrigerators. Attempts to model capillary-tubecharacteristics such as the metastable region, two-phase friction factors and tubewall roughness, critical flow, and two-phase flow regimes have met with limitedsuccess.An experimental facility is presented which is designed to acquire data forconditions including those seen in domestic refrigerators. The facility has capabilityfor independent control of oil concentration, multiple test-section configurations, andinstrumentation for gathering mass-flow, pressure, and temperature data. Alsopresented is a small set of data used to analyze the performance of the experimentalfacility and suggest topics for further investigation.
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