Mist to annular flow development quantified by novel video analysis methods

A mathematical image analysis technique has been developed which allows quantitative measurements of the film and droplets found in annular-mist flows to be extracted from a single video. This method allows measurements to be made without altering the internal geometry or flow path. Flow parameters such as drop size, velocity, and concentration and film wavelength and wave speed are each capable of being measured. A separate video analysis procedure for determining film thickness by critical light reflection was improved to allow measurements to be performed along curved surfaces. By use of these video analysis techniques and by measurement of droplet and film velocities and dimensions at several downstream positions, knowledge of two-phase flow development is furthered. Models from the open literature, which were developed for air-water flows, have been modified based on physical entrainment and deposition mechanisms to allow these models to be used with flows containing fluids with markedly different transport properties, specifically refrigerant-oil flows. While the primary purpose of the model is to predict the development of liquid from the mist to annular regimes, additional models were able to predict the development of film speed, thickness, and wavelength. Furthermore, the understanding of fully-developed annular-mist flows is enhanced by using a miscible two-component liquid with substantially different fluid properties than typically utilized in two-phase flow experiments found in the open literature. While this ability to expand the usage of existing models may prove useful in many fields, it is believed that the knowledge of flow development at the discharge of a compressor will be directly applicable to improved oil separator designs. Additionally, properties of subcooled refrigerant-oil mixtures were measured