Experimental Study on Critical Heat Flux Characteristics of CuO/DIW Nanofluids according to Manufacturing Methods

The critical heat flux (CHF) is characterized by a sudden reduction of the local heat transfer coefficient (HTC) that results from the replacement of liquid by vapor adjacent to the heat transfer surface. Ordinarily, the CHF represents the thermal limitation in which a phase change happens during heating. When the CHF occurs, an inordinate decrease in the heat transfer rate for heat flux controlled system generates, and an inordinate decrease in the heat transfer rate for temperature controlled systems generates. Of the two, the former is generally more important in applications such as power generation because of maintenance of the integrity occurring in heated surface. So, it is very important to enhance the CHF to ensure the system safety and improve the efficiency. Many methods to enhance the CHF have been investigated and a new technique in recent years among these methods is nanofluids technology. Nanofluids are a new class of nanotechnology-based transfer fluids engineered by dispersing and stably suspending nanoparticles in traditional heat transfer fluids such as water, ethylene glycol, and engine oil. The papers about the CHF enhancement according to the different nanoparticles have been reported. But, the paper about the CHF enhancement according to the methods of nanofluids manufacture has been not reported. So, we prepared the pool boiling experiment with nanofluids made by the laser ablation method (one-step method) and the two-step method