https://www.eis.hu.edu.jo/deanshipfiles/pub10311351.pdf

Application of nanofluids for heat transfer enhancement of separated flows encountered in a backward facing step

Research in convective heat transfer on internal separated flows has been extensively conducted in the past decades. This review summarizes numerous researches on two topics. The first section focuses on studying the fluid flow and heat transfer behavior of different types of single-phase fluid flows over backward facing step (BFS) at different orientations. The second section concentrates on everything related to nanofluids; its preparation, properties, behavior, applications, and many others. The purpose of this article is to get a clear view and detailed summary of the influence of several parameters such as the geometrical specifications, boundary conditions, type of fluids, and inclination angle on the hydrodynamic and thermal characteristics using (BFS). The reattachment length and maximum Nusselt number are the main target of such research where correlation equations were developed and reported in experimental and numerical studies. The heat transfer enhancement of nanofluids along with the nanofluids preparation technique, types and shapes of nanoparticles, base fluids and additives, transport mechanisms, and stability of the suspension are also discussed.

Convective heat transfer and fluid flow study over a step using nanofluids: A review

Backward-Facing Step (BFS) flow is one representative model for separation flows, which can be widely seen in aerodynamic flows (airfoil, spoiler, high attack angle process), engine flows, condensers, vehicles (cars, boat), heat transfer systems, and even the flow around buildings, etc. The flow separation after a simple stage will introduce separation bubble formation, evolution and re-attachment process, which is dependent on the BFS geometric design, the inlet and outlet conditions, turbulent intensity, as well as heat transfer conditions. In the past decades, it has been widely studied by various theoretical, experimental and numerical methods. Considering the importance of BFS flow in both theoretical and engineering aspects, this paper is focused on a review study of BFS flows from fundamental understandings to various experimental and numerical developments in a historical viewpoint. Basic models and the parameter-based after-step flow laws are summarized and categorized in this study. It is shown that the step size (duct expansion ratio) will define the basic re-circulation and re-attachment process, while the coupled effects of inflow parameters and the perturbation designs also help shape the flow behaviors after BFS. The review is also extended with model generalizations and the implications on system design, especially the heat transfer effects and the representative control designs are discussed in detail. Future trends and prospects in BFS studies are also included in this study.

A review of Backward-Facing Step (BFS) flow mechanisms, heat transfer and control

Numerical simulation of laminar to turbulent nanofluid flow and heat transfer over a backward-facing step

Application of nanofluids in heat transfer enhancement is prospective. They are solid/liquid suspensions of higher thermal conductivity and viscosity compared to common working fluids. A number of ...

https://journals.sagepub.com/doi/pdf/10.1177/1687814016673569

A survey on experimental and numerical studies of convection heat transfer of nanofluids inside closed conduits

Reverse flow regions in three-dimensional backward-facing step flow

Measurements in three-dimensional laminar separated flow

Numerical simulations for incompressible three-dimensional laminar forced convection flow adjacent to backward-facing step in rectangular duct are performed to examine the reattachment region of the separated flow on the stepped wall. The feasibility of utilizing the two-dimensional flow definition and the limiting streamline definition for identifying the reattachment line/region was examined. The downwash and the jet-like flow that develops near the sidewall creates significant spanwise flow adjacent to the stepped wall, making it difficult to identify a reattachment line/region both numerically and experimentally. The use of the line/region that identifies the location on a plane adjacent to the stepped wall where the gradient of the mean streamwise velocity component is zero (∂u/∂y| y=0 =0) is recommended for code and apparatus validation of three-dimensional separated flow

J. H. Nie

Papers

Reverse flow regions in three-dimensional backward-facing step flow

Measurements in three-dimensional laminar separated flow

Reattachment of Three-Dimensional Flow Adjacent to Backward-Facing Step

Convection in laminar three-dimensional separated flow

Bifurcated three-dimensional forced convection in plane symmetric sudden expansion