Latest developments in nanofluid flow and heat transfer between parallel surfaces: A critical review

The enhancement of heat transfer between parallel surfaces, including parallel plates, parallel disks, and two concentric pipes, is vital because of their wide applications ranging from lubrication systems to water purification processes. Various techniques can be utilized to enhance heat transfer in such systems. Adding nanoparticles to the conventional working fluids is an effective solution that could remarkably enhance the heat transfer rate. No published review article focuses on the recent advances in nanofluid flow between parallel surfaces; therefore, the present paper aims to review the latest experimental and numerical studies on the flow and heat transfer of nanofluids (mixtures of nanoparticles and conventional working fluids) in such configurations. For the performance analysis of thermal systems composed of parallel surfaces and operating with nanofluids, it is necessary to know the physical phenomena and parameters that influence the flow and heat transfer characteristics in these systems. Significant results obtained from this review indicate that, in most cases, the heat transfer rate between parallel surfaces is enhanced with an increase in the Rayleigh number, the Reynolds number, the magnetic number, and Brownian motion. On the other hand, an increase in thermophoresis parameter, as well as flow parameters, including the Eckert number, buoyancy ratio, Hartmann number, and Lewis number, leads to heat transfer rate reduction.

Investigating the Effect of Line Dipole Magnetic Field on Hydrothermal Characteristics of a Temperature-Sensitive Magnetic Nanofluid Using Two-Phase Simulation

Hydrothermal characteristics of a temperature-sensitive magnetic nanofluid between two parallel plates are investigated in the presence of magnetic field produced by one or multiple line dipole(s) using the two-phase mixture model. As the nanofluid reaches the region where the magnetic field is applied, a rotation is developed due to the dependency of magnetization on temperature. This can lead to mixing in the flow and more uniform distribution of temperature due to the disturbance caused in the boundary layer, and consequently, enhancement in convective heat transfer. The results indicate that the disturbance in boundary layer adjacent to the lower wall is more significant than the upper wall. By application of the magnetic field, the convective heat transfer increases locally for both walls. Due to the intensified mixing, a sudden pressure drop occurs when the fluid reaches the region where the magnetic field is applied. For greater magnetic field strengths and lower Reynolds numbers, the improvement in convective heat transfer is more significant. For small magnetic field strengths, the effect of applying magnetic field on the upper wall is much smaller than that on the lower wall; however, this effect becomes almost the same for both walls at great magnetic field strengths.

Distal Humerus Fractures: Open Reduction Internal Fixation

Distal humerus fractures are challenging injuries for the upper extremity surgeon. However, recent techniques in open reduction internal fixation have been powerful tools in getting positive outcomes. To get such results, the surgeon must be aware of how to properly use these techniques in their respective practices. The method of fixation depends on the fracture, taking the degree of comminution and the restoration of the columns and articular surface into account. This article helps surgeons understand the concepts behind open reduction internal fixation of the distal humerus and makes them aware of pitfalls that may lead to negative results.

Fractures of the posterior wall of the acetabulum: treatment using internal fixation of two parallel reconstruction plates

OBJECTIVES

Our aim was to evaluate the efficacy of the treatment method using internal fixation of parallel reconstruction plates for the posterior wall of the acetabulum fractures.

DESIGN

Randomised, prospective.

SETTING

Level I trauma centre.

PATIENTS/PARTICIPANTS

57 patients with posterior wall fractures of the acetabulum in our department from 2007 to 2010 were treated operatively using this technique.

INTERVENTION

internal fixation of two parallel reconstruction plates was used in this study. One of the plates was near the border of acetabulum. The other was parallel to the former one and was located to stress concentrated area.

MAIN OUTCOME MEASUREMENTS

The clinical outcome was evaluated using the clinical grading system and radiological outcome was evaluated according to the criteria described by Matta. In addition, complications were researched in this study.

RESULTS

The percentages of the clinical excellent-to-good and fair-to-poor results were 93.0% and 7%, respectively. We found that clinical outcome had no correlation with age, operation time from injury to operation, nor had correlation with hip dislocation, comminuted fracture condition and marginal compression fracture. Anatomical reduction was significantly correlated with excellent-to-good clinical outcome. Necrosis of the femoral head and heterotopic ossification were prone to decline the outcome of acetabular fractures despite good fracture reduction.

CONCLUSIONS

the internal fixation of two parallel reconstruction plates facilitated rigid fixation and avoided fracture fragment injury, was an effective and reliable alternative method to treat fractures of the posterior wall of the acetabulum.