The influence of surfactant and ultrasonic processing on improvement of stability and heat transfer coefficient of CuO nanoparticles in the pool boiling

•Boiling heat transfer coefficient was improved by adding CuO nanoparticles.•Boiling heat transfer coefficient and stability of nanoparticles was increased by applying ultrasonic waves.•The sediment at the surface of heat transfer was reduced by using ultrasonic waves.•The better performance of applying ultrasonic waves compared to surfactant in improving BHTC was obtained. The present experimental research studied the effects of SDS surfactant (Sodium Dodecyl Sulfate) and ultrasonic waves on the performance and stability of CuO nanoparticles fluid. CuO solution (deionized water-based) used to increase the boiling heat transfer coefficient. Boiling heat transfer coefficient of fluid increases by the addition of nanoparticles into the fluid, but due to the instability of nanoparticles by increasing temperature and time, nanoparticles are precipitated on the heat transfer surface, leading to a reduction in the boiling heat transfer coefficient. To overcome this challenge, two conventional methods were employed including the addition of SDS surfactant (0.05, 0.07 and 0.09 Wt%), and ultrasonic radiation (with 30%, 60%, and 90% of power). The results indicated that the highest enhancement of boiling heat transfer coefficient was achieved 38.93% at nanoparticles concentration of 0.125% along with ultrasonic radiation. Then, by adding of 0.05 wt% surfactant to the solution, the lowest enhancement is obtained 20.11%. [Display omitted]