Pool boiling experiments are generally conducted with electrically heated surfaces in laboratories to obtain the heat transfer coefficient data. In many process applications however, a fluid stream is employed as the heating medium. The heat transfer data generated with the electrically heated test sections therefore raises the question of their applicability to practical equipment design. Simi...

We report a novel boiling heat transfer (NBHT) in reduced graphene oxide (RGO) suspended in water (RGO colloid) near critical heat flux (CHF), which is traditionally the dangerous limitation of nucleate boiling heat transfer because of heater failure. When the heat flux reaches the maximum value (CHF) in RGO colloid pool boiling, the wall temperature increases gradually and slowly with an almos...

Experiments on the flow boiling heat transfer of almost pure CO2 and CO2-oil mixtures in horizontal smooth and micro-fin tubes have been carried out. The smooth tube is a stainless steel tube with an inside diameter of 3mm, and the micro-fin tube is a copper tube with a mean inside diameter of 3.04mm. Experiments were carried out at mass velocities from 190 to 1300kg/(ms), saturation temperatur...

The subjects of heat transfer and cooling system are very important topics in the Internal Combustion Engines (ICE). In modern cooling systems, low weight, small size and high compactness are the critical designing criteria that requires heat transfer enhancement. Boiling phenomenon which is occurred in the water jacket of the ICE is one of the methods to increase heat transfer in the coolant s...

The pool boiling heat transfer coefficient of pure liquids were experimentally measured on a horizontal bar heater at atmospheric pressure. These measurements were conducted for more than three hundred data in thermal currents up to 350 kW.m-2. Original correlations and the unique effect of these correlations on experimental data were discussed briefly. According to the analysis, a new empirica...

Industrial demands for more compact heat exchangers are a motivation to find new technology features. Electrohydrodynamics (EHD) is introduced as a promising phenomenon for heat transfer enhancement mechanisms. Similar to any new technology, EHD has not been understood completely yet and requires more fundamental studies. In boiling phase change phenomena, nucleation is the dominant mechanism i...

Enhancement of pool boiling heat transfer in water by means of the introduction of free particles on the heated surface is investigated. The layer of loose particles on the heated surface is free to move and deform under the action of bulk liquid convection and vapor nucleation. High-speed visualizations show that bubble nucleation preferentially occurs at the narrow corner cavities formed betw...

Local heat transfer coefficients and pressure drops during boiling of the dielectric liquid fluorinert FC-77 in parallel microchannels were experimentally investigated in recent work by the authors. Detailed visualizations of the corresponding two-phase flow regimes were performed as a function of a wide range of operational and geometric parameters. A new transition criterion was developed for...

In order to extend the existing heat transfer coefficient correlation of R410A-oil mixture flow boiling in conventional size (7.0 mm) microfin tube to be suitable for widely used small diameter tubes (4.0~5.0 mm), the experiments of R410A-oil mixture flow boiling inside three small diameter microfin tubes with different outside diameters of 4.0~5.0 mm and different microfin structures were perf...