Experimental Study of Heat Transfer During Quenching of Steel Cylinders in Boiling Nanofluid

Current study was dedicated to explore cooling performance of TiO2 nanofluid. Preliminary tests have shown the possibility of significant improvement of emergency cooling performance by nanofluids in the case of overheated surfaces. Tests that were held during current investigation
 were performed with cylinders of stainless steel, which were used as an overheated surface. The temperature was recorded by a digital system of 3 type-K thermocouples. The object, preheated in a furnace to high temperatures (600–800 °C), was immersed into boiling distilled water.
 Usage of the set of thermocouples allows to determine heat flow in steel cylinder by its temperature distribution. The implementation of emergency cooling was to add a certain amount of nanofluid concentrate to the volume of boiling distilled water. The experiment was continued until the complete
 cooling of the object (up to 100 °C—the temperature of the surrounding liquid). Calculations confirmed increase of heat transfer coefficient for NF and, respectively, about 40% decrease in cooling time for NanoFluid compared to distilled water was observed. Three method of determination
 of heat transfer coefficient were compared.