Eperimental Investigation of Pressure Drop by Using the Superhydrophobic Surfaces

Rad, Vahid | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 52076 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Mousavi, Ali; Nouri Boroojerdi, Ali
  7. Abstract:
  8. Through history, increased energy consumption has been encouraged researchers to improve the performance of energy-using devices. Some researchers believe that hydrophobic surfaces can play an important role in this regard.The encounter and the presence of water on different surfaces can have different effects on them. The surface sedimentation of these surfaces, the eating of metal surfaces, the drag force (water friction) due to water collision with the moving object in water and the attachment of algae And other marine organisms to the surfaces, including the limitations and problems faced by professionals and staff associated with this sector.In the present study, the drag reduction of water flowing through the pipe with superhydrophobic surfaces were investigated. Due to the specific physical and mechanical properties of these surfaces, they widely used in water transfer industries (water pipes, micro-channels, etc.). There are several methods for creating the desired morphology on the surface, in which the chemical etching method has been investigated. In the next step, hydrophobicity has been applied to the roughened surface. This aim of manufacturing is done with the using of nanoparticles; aluminum oxide nanoparticles( ) are chosen for this purpose. These nanoparticles are hydrolyzed by using a stearic acid solution and hexamethyldisilazane(HMDS) and then placed in these solutions at appropriate concentrations (which have hydrophobic properties) and coated with a spray on a prepared surface (prepared in the previous steps). After the surface of the coated tubes is made, the amount of reducing in pressure drop of different pipes are compared with each other.The experiments were performed at the Reynolds numbers ranging from 24,000 to 34,000 The results showed that the drag reduction ranged from 5.49% to 17.02% for superhydrophobic surfaces
  9. Keywords:
  10. Superhydrophobic Surfaces ; Water Transfer ; Nanoparticles ; Pressure Drop

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