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ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
Evaluation of two-phase flow patterns using chromatic confocal microscopy
Submission Author:
Fernando Neves Quintino dos Santos , SP , Brazil
Co-Authors:
Fernando Neves Quintino dos Santos, Cristiano Tibiriçá
Presenter: Fernando Neves Quintino dos Santos
doi://10.26678/ABCM.ENCIT2022.CIT22-0263
Abstract
Two-phase flows have important applications in fields such as oil and gas industries, refrigeration and power generation. In these flows, the phases have numerous dispositions, called flow patterns, according to the operative conditions, such as mass flow, temperature, flow inclination, fluids, and others. The flow pattern has a strong influence on several parameters, which motivated the creation of various flow pattern maps. While important, its determination is usually subjective, using videos or photos from high-speed cameras. In addition, there is no consensus on the nomenclature, as the same flow pattern can be classified in various ways by researchers. Objective flow pattern classification methods exist, such as statistical analysis or comparing change of inclination on a pressure drop curve, which motivates research on the topic. This paper addresses the issue, proposing a new flow pattern detection technique, using the output signal of the chromatic confocal microscopy, which is an optical instrument that provides distance measures of interfaces between transparent mediums, used mostly in health sciences, and novel in two-phase flow applications. The technique consists of calculating the probability density function of the sensor’s output, and comparing it with the observed flow pattern. The probability density function of each flow is different, and thus can be used to determine transitions. To validate the technique, stratified and intermittent flow patterns were observed on a horizontal air-water flows in a 6.40× 5.0mm2 (b × h) and a 12 mm squared channel. Results pointed that stratified and intermittent flows have a very distinct patterns, encouraging the development of the technique.
Keywords
Two-phase Flow, air-water, flow pattern, chromatic confocal microscopy
