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Experimental Study of Internal Forced Convection of Ferrofluid Flow in Magnetizable Porous Media

Keshavarz Behrghani, Mohsen | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 49108 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Shafii, Mohammad Behshad
  7. Abstract:
  8. The use of nanofluids to improve the heat transfer has a special attention in the industry. researches focus on the efficiency of heat transfer nanofluids dates back to 1998. Ferrofluids are a particular type of nanofluids which their nanoparticles have magnetic effect and heat transfer can be increased by applying magnetic field to them. In this work, thermal and hydrodynamic performance of ferromagnetic fluid which flows through a copper tube in thermal entrance region has been studied. The flow in the tube is laminar and is affected by constant heat flux. Part of the tube contains a porous medium with paramagnetic properties and porosity of 0.46. Ferrofluid is composed of F e3O4 and water with (CH3)4NOH as a surfactant that is prepared in three different volume fractions. The effect of constant and oscillating magnetic field on convective heat transfer coefficient were examined for various Reynolds number, frequencies and volume fractions. The results show that the Maximum enhancement of average heat transfer coefficients of Ferrofluid in magnetizable porous media is 9% and 38.66% in comparison with no magnetic field condition and distilled water respectively. This enhancement reduces to 6.39% and 36.13% for non magnetizable porous media.As a result of experimental studies, using porous media increases heat transfer coefficient significantly, this enhancement is more obvious at the beginning of porous media. Constant magnetic field has no effect and in most cases negative effect on heat transfer enhancement of Ferrofluid. Variable magnetic field increases heat transfer coefficient. This improvement is greater in magnetizable porous media. Increasing volume percentage of Ferrofluid augments heat transfer. Reynolds number has this effect too. There is an optimum frequency for each magnetic field mode. It has the most improvement on heat transfer
  9. Keywords:
  10. Ferrofluid ; Magnetic Fields ; Convection Heat Transfer ; Convective Forced Heat Transfer ; Magnetizable Porousmedia

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