Numerical investigation on thermal–hydraulic characteristics in a mini-channel with trapezoidal cross-section longitudinal vortex generators

Abstract

The stringent requirement and rapid increase in heat dissipation for the high heat flux devices have brought great challenges to cooling performance of mini-channel heat sink (MCHS). Longitudinal vortex generator (LVG) is an effective technology for heat transfer enhancement in MCHS. It remains unclear, however, what effects of LVG cross-section on the thermal–hydraulic characteristics of MCHS are. Herein, a new mini-channel with trapezoidal cross-section LVGs is designed, as well as the effects of front width (a), back width (b) and height (h) of trapezoidal cross-section LVG on local and overall thermal–hydraulic characteristics are explored at the Reynolds number (Re) of 347–868 using numerical simulation method. As results, comparing with rectangular cross-section LVG, trapezoidal cross-section LVG mostly brings better thermal performance, and trapezoidal cross-section LVG with a > b generally performs better comprehensive performance. The best comprehensive performance can be achieved as h equivalents to half of channel height. The recommended optimal parameters are a = 0.6 mm, b = 0.3 mm and h = 0.75 mm to obtain the best comprehensive performance, yielding the maximum performance evaluation criterion (PEC) of 1.756 at Re = 543. Furthermore, comparing to previous studies with LVG, the PEC in present study is better at studied range of Re. Overall, the trapezoidal cross-section LVG as a new and effective technology with optimal parameters is conducive to heat transfer enhancement and comprehensive performance improvement in MCHS.