Loading...

Experimental Study of Pool Boiling Heat Transfer Enhancement by Presence of Magnetic Particles under the Influence of Magnetic Field

Feizbakhshi, Morteza | 2010

656 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 40380 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Behshad Shafii, Mohammad
  7. Abstract:
  8. Study on pool boiling heat transfer characteristics of water-based magnetic fluid and distilled water containing micro size particles has performed. Different concentration in each experiment has been studied to investigate the effect of magnetic fluid and micro size particles on boiling heat transfer on horizontal plate heater. The nickel particles was used as micro size particles which is expected to increase thermal performance of water due to high thermal conductivity of nickel. Experimental results showed adding nickel micro size particles to water can deteriorate the boiling heat transfer coefficient. However the amount of deterioration was the same for all concentrations of nickel particles. Another experiment is done by employing magnetic fluid as working fluid in boiling. The magnetic fluids contain nano-scale Fe3O4 particles which are disperse within the base fluid by means of surfactant. However, results indicated thermal enhancement by increasing magnetic fluid concentration in dilute solution. During each of those experiments, evidence showed a thin layer of deposited particles on heating surface which lead to altering heat transfer performance of boiling. The effect of particle coating on heater has been measured directly by experiment of pure water on coating surface. In this case, the surface coated by micro particles showed degradation and the surface coated by boiling of magnetic fluid showed enhancement. Another experiment has carried out by applying magnetic field on heating surface. Two types of magnetic field including permanent and pulsing field has been tested. Both magnetic fluid and nickel particles showed no appreciable change of heat transfer by applying pulsing magnetic field. But, by using permanent magnetic field and strengthening the field, magnetic fluid showed decrement in heat transfer coefficient which is due to pulling down the particles toward heating surface. The downward force act on particles causes flowing the fluid toward heating surface and therefore interrupting bubble growing and departure process.
  9. Keywords:
  10. Nuclear Boling ; Microparticles ; Magnetic Fields ; Nanoparticles ; Ferrofluid

 Digital Object List

  • محتواي پايان نامه
  •   view

 Bookmark

No TOC