Molecular dynamics simulation of interfacial heat transfer behavior during the boiling of low-boiling-point organic fluid

Boiling heat transfer of low-boiling-point working fluid is one of the promising heat dissipation technologies commonly used in electronic equipment cooling. The study on interfacial heat transfer mechanism is of great significance to improve both heat removal capacity and heat dissipation efficiency. In this work, 1,1,1,2-tetrafluoroethane (R134a) was used as the working fluid, and the interfacial boiling behavior of R134a under different initial thicknesses of liquid film (delta(0)), solid-liquid interaction force and initial temperature (T-0) was analyzed by molecular dynamics (MD) method. In the simulation, delta(0) changes from 2.5 to 7.5 nm, the energy coefficient (alpha) characterizing solid-liquid interaction force changes from 0.25 to 4, T-0 ranges from 180 to 200 K, and the temperature difference between the solid substrate and the liquid film is 220 K (i.e., the superheat for boiling). The results show that only delta(0) could significantly alter the boiling mode of R134a.When delta(0) = 2.5 nm, it shows thin film boiling, otherwise as delta(0) gets thicker, it shifts into explosive boiling mode. Under the explosive boiling mode, the total thermal resistance (R-tot) consists of three parts, i.e., the solid interface thermal resistance (R-W), thermal resistance of vapor layer (R-V), and vapor-liquid interface thermal resistance above layer (RV-L). R-V contributes the most to R-tot. However, during the thin film boiling, only R-W contributes to R-tot. With the increase of delta(0) and alpha, R-tot presents the similar trend, i.e., increasing first and decreasing afterwards. When delta(0) = 7.5 nm and alpha is 1, R-tot reaches to the highest value of 3.49x10(-8) K center dot m(2)/W. For the influence of T-0, it oppositely affects R-tot. Overall, the increase of alpha and T-0 and the decrease of delta(0) are all beneficial to accelerate the boiling of R134a.

Automated summary

The boiling heat transfer of low-boiling-point working fluid is a common heat dissipation technology in electronic equipment cooling. This study analyzed the interfacial boiling behavior of R134a under different conditions and found that factors such as the initial thickness of the liquid film, solid-liquid interaction force, and initial temperature significantly affect the boiling mode and thermal resistance.