CFD modeliranje laminarnog strujanja i prenos toplote korišćenjem nanofluida baziranog na vodi i Al2O3 u fin cevi sa ukrivljenom trakom

Laith Habeeb,Bassim Maajel,Fouad Saleh

doi:10.5937/fmet1901089h

Abstract

This study investigates numerically heat transfer augmentation using water-based Al2O3 nanofluid flowing in a circular cross-sectional tube under constant inlet temperature in laminar flow conditions. The Al2O3/water nanofluid with different volume fractions (3% and 5%) and twisted tape twist ratio of (H/D =1.85) are employed, and Reynolds numbers of 678 to 2033 in a laminar flow are considered. The numerical analysis is used to solve the governing partial differential equations in three dimensions. Results of the flow structure, velocity vector, and temperature field are reported. The numerical results indicate that the heat transfer rate becomes more remarkable when employing nanofluid. The maximum 46% enhancement is obtained in the convective heat transfer coefficient by using Al2O3/water nanofluid at 5% particle volume fraction and Reynolds number of 678, comparing with pure water. It is also found that heat transfer enhancement increases with an increase in the particle volume concentration and Reynolds number.

Highlights

In the past decades, many different techniques have been utilized in various energy providing devices to improve the poor thermal performance of conventional heat transfer fluids which are widely used in many industrial cooling or heating applications
The results showed that the V-cut twisted tape with twist ratio (y = 2.93) and cut depth (w = 0.5 cm) present a maximum heat transfer rate with significant increase in friction factor
This work presents a numerical investigation of heat transfer performance of finned tube with twisted tape inserted

Summary

Introduction

Many different techniques have been utilized in various energy providing devices to improve the poor thermal performance of conventional heat transfer fluids (water, engine oil, and ethylene glycol) which are widely used in many industrial cooling or heating applications. There are different ways existing for increasing heat transfer in heat exchangers, that can be divided into two groups: active and passive. An enhancement in heat transfer using a nanofluid is a method presented by Choi [1]. Nanofluid is a new class of heat transfer fluids. The use of nanofluids for heat transfer enhancement is one of the passive heat transfer techniques employed in many heat transfer applications. A large number of studies have conducted numerically to determine the convective heat transfer characteristics of nanofluids in laminar flow regimes

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