This study investigates the effect of different surfactants on Al2O3 nanofluids during the down-heating process. By doping Al2O3 nanofluid with a mass concentration of 12 mg/L with various surfactants, such as sodium dodecylbenzene sulfate (SDBS), sodium dodecyl sulfate (SDS), and gum arabic, pool boiling experiments were conducted to evaluate their thermal conductivity and stability. The experimental results showed significant differences in the enhancement of critical heat flux and the heat transfer coefficient among the different surfactants, with gum arabic exhibiting the best performance, followed by SDBS, and SDS, which showed the least enhancement. The study also found that the concentration of surfactants plays a crucial role in affecting the overall heat transfer performance and stability of nanofluids. The experimental group of 24 mg/L gum arabic doped into the Al2O3 nanofluid showed the best heat transfer performance. Highlights include the following:

1. The whole process of boiling heat transfer of alumina nanofluid was recorded.

2. Different surfactants enhance the critical heat flow density of alumina nanofluids to different degrees.

3. The effect of surfactant type and concentration on surface properties and heat transfer performance was analyzed.

4. Microlevel analysis was conducted for the enhancement of heat transfer properties of alumina nanofluids by gum arabic.