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Abstract
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In this work, pH, surfactant, and ultrasonic waves as important stabilizers in decreasing the nanoparticles’ deposition in the pool boiling were investigated. After determining the optimum parameters of the nanofluid of c-Al2O3, the effects of applying the three stabilizers on the boiling heat transfer coefficient were studied. The best performance was determined at pH 10, sodium dodecyl sulfate (SDS) surfactant’s concentration of 0.06 wt.%. In addition, three parameters of the ultrasonic waves were optimized at 50% power, 21 min of ultrasonic irradiation and cycle of 0.5–0.5. The results demonstrated that the ultrasonic waves’ irradiation with an average of 6.79% more than pH 10 and 7.13% compared to the SDS surfactant played a significant role in attaining the maximum heat transfer coefficient. The atomic force microscopy analysis verified the heat transfer coefficient’s variations due to sedimentations on the heat transfer surface. Finally, nanofluids of c-Al2O3 and CuO were also compared.
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