# Effect of Nanofluids on Boiling Heat Transfer Performance
## 1 Introduction
Results revealed that bubble formation induces a pressure drop within the test section. Heat flux had no influence on the pressure, while an increase in the fluid flow rate caused an increase in the pressure drop. It was also found that the heat transfer coefficient decreased with operating time due to the presence of nanoparticles on the boiling surface resulting in the creation of thermal resistance on the surface. Also, an asymptotic behavior for the fouling thermal resistance over the time was registered. The maximum enhancement for the heat transfer coefficient was 23.7% at wt.% = 0.1. For wt.% = 0.2 and wt.% = 0.3, the maximum enhancement of 16.2% and 13.3%, were achieved, respectively. At the same time, [PERSON] [22] et al. found that by increasing the applied heat flux, the flow boiling heat transfer coefficient increases for both test fluids at both heat transfer regions. In addition, by increasing  
Figure 1: Boiling curve [20]. the flow rate of fluid, the heat transfer coefficient dramatically increases at both regions. Furthermore, higher heat transfer coefficient can be obtained due to interactions of bubbles and local agitations. In addition, Author experimentally measured the nucleate pool boiling heat transfer coefficients of Al\({}_{2}\)O\({}_{3}\)-water and Ti\({}_{2}\)O-water nanofluids on three horizontal tubes with different materials and similar roughness [25]. Results revealed that presence of nanoparticles in the base fluid leads to an increase in pool boiling heat transfer coefficients on stainless steel and brass tubes in contrast to copper tube. Presence of nanoparticles had no effect on the pool boiling heat transfer coefficient for the copper tube. Variations of surface excess temperature for the copper tube were higher in comparison with that of the other tubes tested. [PERSON] [26] et al. experimentally studied the pool boiling heat transfer characteristics of gamma Fe\({}_{3}\)O\({}_{4}\) aqueous nanofluids on a flat disc heater. The nanoparticle mass concentration was 0.1-0.3% and the heat flux was 0-1546 kW/m\({}^{2}\). Results indicated that the pool boiling heat transfer coefficient increases with increasing the mass concentration and applied heat flux. In addition, the rate of bubble formation is significantly intensified at higher heat fluxes, and subsequently larger bubbles detached from the surface due to the intensification of bubble coalescence. In terms of fouling formation, it can be stated that fouling of nanofluids is a strong function of time and rate of deposition is increased over the extended time while the pool boiling heat transfer coefficient was not decreased over the time, as the porous deposited layer on the surface detached from the surface by bubble interactions. In terms of critical heat flux, capillary action of the deposited layer was found to be the main reason responsible for increasing the critical heat flux as liquid is stored inside the porous deposited layer, which enhances the surface toleration against the critical heat flux crisis. The nanoparticles can increase the thermal conductivity of the base fluid. In addition, the deposition of nanoparticles can reshape the heated surface, thereby affecting the boiling heat transfer performance. So the summary of this article were shown below. 1. Application of nanofluids. 2. Effect of nanoparticle type on boiling heat transfer. 3. Effect of base fluid type on boiling heat transfer. 4. Outline the effect of nanofluids on boiling critical heat flux. 5. Outline the effect of nanofluids on boiling heat transfer coefficient. This paper summarizes the existing literature and understands the research and value of nanofluids in different application fields, providing readers with a relatively macroscopic understanding. The disagreement and differences in the effects of nanofluids on the boiling heat transfer coefficient [27; 28] are explained by the heated surfaces, boiling bubbles, and the microscopic motion of nanofluids. It also provides some ideas for future research for nanofluids.