Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : July 10, 2017 - July 12, 2017
The purpose of this paper is to analyze the characteristics of a gas-liquid two-phase flow passing through a thin tube that includes expansion and contraction junctions. The fluid is refrigerant R134a. The refrigerant evaporates with decreasing pressure while it is passing through a thin tube. The experiments are conducted in a flow visualization device that is 0.5 mm in a thin tube diameter, 10.0 mm in its length, and 1.0 mm or 2.0 mm in contraction and expansion tube diameter. The flow characteristics are evaluated concerning the expansion and contraction diameter and the local pressure in the thin tube, and the phase transition of refrigerant flow is quantitatively analyzed by visualization with a high-speed camera and luminance intensity profile. Then, flow patterns that are analyzed by visualization are compared with that of Rémi Revellin. As a result, the local pressure drop in a thin tube is influenced by inlet pressure and the contraction and expansion diameter ratio to the thin tube. From the luminance analysis, the refrigerant in the thin tube transitioned from a bubbly flow to an annular flow. These results are compared to the extended flow pattern diagram of Rémi Revellin
