Bradshaw, Craig R.Shepard, Kyle Allen2025-01-132025-01-132024-07https://hdl.handle.net/20.500.14446/345754Oil-refrigerant mixture foaming is common in compressors found in many HVAC systems. Low-GWP refrigerants, particularly HFOs and blends, have under-studied foaming behavior and characterizing and understanding foaming behavior is necessary for the integration of new refrigerants in vapor compression cycles. In this work, an apparatus is designed and fabricated to study oil-refrigerant pairs in three manners: 1) physical foaming characterization, 2) measurement of dynamic surface tension between oil-refrigerant media, and 3) measurement of oil-refrigerant solubility data. Foaming is generated through pressure drop by charging and heating a chamber of refrigerant and oil and rapidly connecting it to a low-pressure chamber. Dynamic surface tension data is measured in post-processing via maximum bubble pressure tensiometry (MBPT). Foaming and dynamic surface tension experiments are visually recorded with a custom made, high-pressure sight glass which utilizes pressurized water to attain higher internal oil-refrigerant pressures. Physical characterization of foaming and bubbles is carried out in post-processing with camera-tracking software. Solubility is experimentally determined with a circulation loop containing a viscometer and a densitometer and thermodynamic correlations. The completed apparatus will be used to characterize the behavior of 11 pairs of refrigerant-lubricants including various viscosity grades of mineral oil, POE, PAG, and PVE lubricants paired with HFC and HFO refrigerants.application/pdfCopyright is held by the author who has granted the Oklahoma State University Library the non-exclusive right to share this material in its institutional repository. Contact Digital Library Services at lib-dls@okstate.edu or 405-744-9161 for the permission policy on the use, reproduction or distribution of this material.Thesis