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CFD Simulation of Heat Transfer Using Nanofluids in Microchannel Having Dimples and Protrusions

  • Rahul Kunnath
  • K. Neelima chowdary
  • A. Venu VinodEmail author
Conference paper

Abstract

Microchannel heat sinks are highly efficient cooling devices in electronic field. In this study, heat transfer characteristics of CuO–H2O nanofluid flowing through a microchannel having dimples/protrusions, were investigated using CFD package FLUENT 15.0. A constant heat flux of 5 × 105 W/m2 was uniformly applied on all four walls. Nanofluid enters the microchannel at 300 K under fully developed flow conditions. SIMPLE (Semi Implicit Method for Pressure Linked Equations) algorithm was used in the solution procedure. A second-order upwind scheme was used to solve the momentum and energy equations. The dimples/protrusions are arranged on the wall of microchannel either in aligned or in staggered manner. 3-D numerical simulations were carried out at various Reynolds numbers (100, 300, 500, 700). The heat transfer characteristics were obtained for various geometries by varying inlet velocity (1.2–8.7 m/s) and volume fraction (0–4 %) of nanofluid. Wall temperature of microchannel was found to be lower for higher values of velocity and nanoparticle volume fraction, indicating better transfer of heat from wall to fluid. The enhancement in heat transfer was evaluated by a parameter known as thermal performance (TP) which is a function of Nusselt number (Nu), friction factor (f). Entropy generation rate was determined to find optimal geometry. It was found that microchannel with dimples and protrusions and 4 vol.% CuO nanofluid gave the maximum heat transfer enhancement.

Keywords

Heat transfer Microchannel Nanofluids Thermal performance 

List of Symbols

knf,kp,kb

Thermal conductivity of nanofluid, nano particles and base fluid (W/m K)

µnf,µb

Viscosity of nanofluid, base fluid (Pa · s)

ρnf,ρb, ρp

Density of nanofluid, base fluid, nanoparticles (kg/m3)

Cpnf,Cpb,Cpp

Specific heat of nanofluid, base fluid, nanoparticles (J/kg K)

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Copyright information

© Springer Science+Business Media Singapore 2016

Authors and Affiliations

  • Rahul Kunnath
    • 1
  • K. Neelima chowdary
    • 1
  • A. Venu Vinod
    • 1
    Email author
  1. 1.Department of Chemical EngineeringNational Institute of Technology WarangalWarangalIndia

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