Thermal performance analysis of a novel letter-type fin liquid cooling plate based on the field synergy principle and the second law of thermodynamics

In order to expand more forms of liquid-cooled plate fin construction, based on the traditional geometric fins and letter-type fins, a new idea of constructing a new type of letter-type fins by the geometric expansion method is proposed, and then a fin structure design with better heat transfer performance than the traditional geometric fins is explored. Firstly, the validity of the CFD model and method is verified by heat dissipation experiments. On this basis, the flow behavior and heat transfer performance of 6 letter-type fin structures at different Reynolds numbers are numerically investigated, and the synergism and thermal irreversibility of the flow and temperature fields are discussed and analyzed. According to the findings, the field synergy of the new letter-shaped fins is more significant and effectively reduced the irreversibility of heat transfer. In addition, the combined thermal performance analysis shows that the combined heat performance of C-type fins is better when the Reynolds number range is between 49.85–199.4 (HTPF = 1.098–1.57), and the combined thermal performance of T-type fins is better when the Reynolds number range is 249.25–398.8 (HTPF = 1.03–1.07). Secondly, in order to improve the liquid-cooled plate’s heat performance the paper discussed and optimizes the combination mode of C- and T-type letter fins. To further improve the liquid-cooled plate’s thermal performance, on the basis of the optimal combination of fins, we discuss the effect of fin break distance on the liquid-cooled plate’s thermal performance. Finally, secondary fins are introduced to further optimize the liquid-cooled plate’s thermal performance. It is found that a reasonable setting of secondary fins can effectively reduce the pressure drop of the liquid cooling plate and improve the comprehensive heat dissipation performance (18.71 %∼32.09 %).