Is a non-phase change heat pipe a new heat pipe?

A Non-phase change heat pipe (NPCHP) with no wick was proposed recently as a new heat pipe which is not dependent on a wick or phase change at steady state operation and where heat transfer is driven by the pressure response to a heat input, rather than phase change. The NPCHP is not a new device as suggested but is a loop thermosyphon with very high fill ratio. This effort focuses on proving the NPCHP, as an overfilled loop thermosyphon, is an effective heat transfer device through experiments and numerical simulations. An analysis of the operation and effectiveness of the device is performed, and it is shown to exhibit several heat transfer characteristics of a heat pipe, including high thermal conductivity and a fast thermal response time. Depending upon the initial fill ratio of the NPCHP, the device is shown to either operate as an overfilled two-phase loop thermosyphon or a single-phase loop thermosyphon. The NPCHP exhibits characteristics of a loop thermosyphon and can be classified as such. (C) 2019 ElSevier Ltd. All rights reserved.