English

Active biphasic heat transfer enhancement in vertical natural convection

Fluid Dynamics 2025-08-11 v2

Abstract

Vertical natural convection (VC), often cannot meet the high heat transfer demands due to the inherent misalignment of the direction of buoyancy (vertical) with the direction of the heat transfer (horizontal). Here we applied a novel strategy on a water based VC system to enhance the heat transfer. By adding 2% of the total volume with a low-boiling-temperature liquid (HFE-7000) and introducing a gas-liquid layer on top of the VC cell, we create a self-sustained state of pseudo-turbulence with evaporating, circulating and condensing biphasic bubbles. The system achieves 246% heat transfer enhancement at constant superheat Tsup6.4KT_{sup}\approx6.4 \text{K} when the liquid in the full nucleate boiling state. Using shadowgraphy and Laser Doppler Anemometry (LDA) methods, we validate that the bubbles and biphasic particles induced agitation enhances the heat flux and modifies the temperature field of the heat transfer.

Keywords

Cite

@article{arxiv.2508.01262,
  title  = {Active biphasic heat transfer enhancement in vertical natural convection},
  author = {Haoran Qi and Chaoben Zhao and Yaning Fan and Yihong Du and Varghese Mathai and Chao Sun},
  journal= {arXiv preprint arXiv:2508.01262},
  year   = {2025}
}