Characterizing the Discharge Quality for a Two-Phase Pumped Loop

Date of Award


Degree Name

M.S. in Mechanical Engineering


Department of Mechanical and Aerospace Engineering and Renewable and Clean Energy


Advisor: Jamie Ervin


A two-phase pumped refrigerant (R-134a) loop was developed. An energy balance experiment was performed for the preheater, where calculated refrigerant volumetric flow rates differed by no more than 5% from measured flow rates. An energy balance was performed as well for the entire system, and calculated water volumetric flow rates differed by no more than 14% from measured flow rates. A model of the preheater and its power input was constructed and compared to experimental power inputs. The model time constant was 224 seconds and the experimental time constant was 194 seconds. Specified operating conditions were 5 kW heat input to the cold plate with a 96.6 psia discharge pressure. System operating boundaries for this setup were plotted as cold plate inlet subcooling and discharge quality both as functions of preheater input power and pump speed. Preheater power inputs ranged from 0 to 95% full-scale power (0 to 782 W) and pump speeds ranged from 60 to 100% full-scale speed (0.41 to 0.73 GPM). Within operating boundaries, vapor quality was kept at a value of 0.8 or lower. It is very useful to know the boundaries for the system, which could be used for future two-phase pumped loop systems.


Mechanical Engineering, two-phase, quality, pumped loop, refrigerant, MPCL

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Copyright 2018, author