**Preface to "Heat Transfer and Fluids Properties of Nanofluids"**

This reprint comprises twelve high-quality articles covering a wide range of important research topics on nanofluids.

The first article by Ali and co-workers reviews the state-of-the-art research on popular carbon-based nanofluids and their applications in thermal and energy systems.

A forced convection study on thermal and hydraulic performances of nanofluids containing carbon, and Al2O<sup>3</sup> and SiO<sup>2</sup> nanoparticles in PEG in a fully developed turbulent flow in a square, heated pipe is reported by Afan and co-workers in the second article.

In the third article, Giwa and co-authors performed a characterization of the morphology and stability of dispersed nanoparticles and determined the viscosity and electrical conductivity of DW-based MWCNT-Fe2O<sup>3</sup> hybrid nanofluids at different temperatures and concentrations.

A numerical investigation to assess the effects of polydispersity and sintering on the effective thermal conductivity of nanoparticles' aggregates conducted by Karagiannakis and co-workers is reported in the fourth article.

The fifth article presents the thermal performances of DW-based Al2O<sup>3</sup> and TiO<sup>2</sup> nanofluids in a compact plate heat exchanger by comparing experimental and numerical investigations performed by Ajeeb and Murshed.

In the sixth article, Zhang and co-workers determined isotherms, streamlines, and heat transfer rates under various conditions and parameters by employing the Darcy–Brinkman and energy transport equations in a numerical study of natural convection heat transfer in a porous annulus filled with a Cu nanofluid.

Ahmed and co-authors presented a numerical investigation of the impacts of melting on the convective flow of Al2O3-based PCM within cylindrical tubes containing cross-shape heated sections in the seventh article.

The eight article reports a numerical study on the natural convection within an inversed T-shaped enclosure filled by NePCM conducted by Abderrahmane and co-workers.

Pereira and co-authors reported a review of the possible mechanisms and characteristics of nanoparticle deposition and its impact on various factors such as surface roughness and wettability, the density of vaporized core points, and thermal resistance in the ninth article.

The tenth article presents an experimental study on the effects of nanoparticle size and concentration on pool boiling heat transfer with TiO2 nanofluids on laser-textured Cu surfaces conducted by Hadziˇ c and co-workers. ´

A numerical study on the appearance of a solitary wave particle concentration in nanofluids under a light field conducted by Livashvili and co-authors is reported in the eleventh article.

The final article reports on a molecular dynamics simulation of the behaviors of water nanodroplets impinging on moving surfaces performed by Zhang and co-authors.

The Special Issue Editor acknowledges all the authors for their valuable contributions to the book and the Reviewers for assessing the quality of each article.

> **S M Sohel Murshed** *Editor*
