Determination of Void Fraction in Separated Two-Phase Flows Using Optical Techniques
نویسندگان
چکیده
Experimental determination of void fraction in two-phase flows can be achieved in a number of different ways, including: the quick closing of valves at each end of a test section, impedance measurement techniques, gamma or x-ray absorption, and analysis of visualization results. This paper presents a method of determining void fraction in separated, two-phase refrigerant flows through analysis of images obtained through high speed visualization. A statistical technique known as Change Point Analysis was used to automate the determination of the location of the liquid/vapor interface in stratified and intermittent type flows. This determination allows for a calculation of the void fraction in these separated flows that can be examined as a function both of time (different images) and length (location within the image). The developed technique was applied to visualization results of separated R134a flows in transparent tubes with diameters of 7.2mm, 8.7mm, and 15.3mm.
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