Study on Characteristics of Thermal Flow-Induced Vibration in Unlooped Heat Pipe

In this paper, presented is an experimental study of thermal flow-induced vibration in a both-ends-closed type self-induced oscillating heat pipe. This was made of winding glass tube to visualize the phenomenon. It was heated at the bottom to control temperature by heater, while was cooled at the top to keep temperature constant. Liquid column oscillation was excited with boiling and expansion of vapor plug. When liquid volume fraction was large, the magnitude of pressure oscillation was large and low frequency was relatively dominant. Furthermore, normalized temperature θ_t was proposed to investigate the threshold of excited conditions, taking account of initial condition, e.g. initial pressure. With respect to liquid volume fraction, θ_t was alternately varied up and down. This phenomenon was evaluated to be dependent on the liquid volume fraction.