Numerical simulation and experimental study of gas–liquid two-phase flow pattern of hydrodynamic retarder

The internal flow of hydrodynamic retarder is a three-dimensional, complex, viscous, and unstable gas–liquid two-phase flow. The importance of numerical simulation of a hydrodynamic retarder has been paid attention to, but the research on the two-phase flow pattern of the retarder is rarely. Flow pattern diagnosis plays an important role in the study of two-phase flow because the premise of establishing the mathematical model of the two-phase flow is to accurately determine the flow structure of the flow system. Based on the numerical simulation and experimental research, this study found the corresponding relationship between the two-phase flow distribution inside the hydrodynamic retarder and the filling rate (expressed as “q”). The result shows that, when q = 0.1–0.2, the liquid in the working chamber is less. Under the action of centrifugal force, the liquid mainly gets distributed in the outer ring of the circulating circle, forming a laminar flow. When q = 0.3–0.4, the flow pattern of the gas–liquid two-phase flow changes from the laminar flow to slug flow. When q = 0.5–0.9, with a further increase in the filling ratio, the flow becomes a dispersed bubble flow. This paper provides an effective method for the analysis and identification of the two-phase flow pattern of a hydrodynamic retarder.