Flow development in the discharge of a compressor.

Compressors produce a flow of oil droplets propelled by refrigerant flow while fully developed flow maps predict predominantly annular flow. This discrepancy is rooted in the lack of understanding of flow development. A newly developed video processing technique was used to quantify numerous flow parameters. The measured drop size, drop speed, drop concentration, film thickness, and film velocity were used to determine the migration of oil between drops and film as it flows from the discharge of a compressor. A model has been created to describe the development of flow leaving a compressor as it transitions from mist to annular flow. Parameters such as refrigerant flow rates, oil in circulation ratios, and fluid properties are accounted for in these models. While some flow development literature modeled deposition or entrainment for air-water or steam-water flows, little work is available for air-conditioning applications. Due to the drastically different properties of refrigerant-oil mixtures from air-water mixtures, the existing models were modified using physical principles to incorporate the differences in fluid properties. The model closely approximates empirical results from the measurements as well as published values.