Visualization Experiments of Radial-Rotating Oscillating Heat Pipe Filled with Methanol

Abstract

Oscillating heat pipes (OHP) have highly efficient heat transfer capability. Some researchers have applied OHPs to cutting tools and rotating machines by embedding tubular OHPs in machines or by making flow channels on metal plates. Most studies are on heat transfer performance, and there are few studies on the heat transfer behavior of radial-rotating oscillating heat pipes (RR-OHP) under operating conditions. This paper conducted the visualization test of an RR-OHP filled with methanol by studying the flow patterns and motion modes at rotation speed (0-860 rpm) and heat flux (20000-40000 W/m2). When the heat flux is increased from 20000 W/m2 to 40000 W/m2, the flow patterns include flowless, slug flow, annular flow, and churn flow, and the motion modes contain oscillatory motion, cyclic motion, unilateral boiling, and bilateral boiling. The distribution map of the flow patterns and motion modes with the centrifugal acceleration and the heat flux was plotted, which shows the evolution of the flow patterns and the transformation of the motion modes of the RR-OHP, and elucidates the effect of the centrifugal acceleration and the heat flux on the flow patterns and motion modes.