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Yongling Zhao

yongling zhao picture

BE, MEngSci (Adelaide)
Postgraduate Research Student
Environmental Fluid Group



School of Civil Engineering, Room 360
Phone: +61 2 9351 5155
Fax: +61 2 9351 3343
Email:

Research project - Enhancement of heat transfer by natural convection

Supervisor: A/Prof Chengwang Lei
Associate Supervisor: Prof John Patterson

When a vertical hot surface is present in a stationary fluid, heat is conducted into the fluid from the hot surface, during which a buoyancy-induced vertical flow develops and carries away the heat. This flow is known as natural convection, which is the basis of many engineering applications, such as heating of living spaces and cooling in electronic devices.

One significant feature of natural convection is that the heat from the vertical heated surface is dissipated through a thin layer of fluid adjacent to the heated surface, i.e. a thermal boundary layer. Therefore, manipulating the boundary layer flow to enhance natural convection heat transfer is of particular interest and significance. Recent investigations by Xu et al. (2008, 2009) have demonstrated an innovative way for enhancing heat transfer by manipulating the thermal boundary layer flow. By attaching a short horizontal fin to a heated wall, the downstream boundary layer is perturbed by a plume flow arising from the thermal flow bypassing the fin (see the figures below), resulting in heat transfer enhancement in the downstream section of the heated surface.

In this project, Yongling will extend the previous investigations on the enhancement of natural convection heat transfer. The aim of this project is to propose and investigate other innovative ways to manipulate the thermal boundary layer flow for enhancing natural convection heat transfer. This will be achieved based on a thorough understanding of the thermal boundary layer flow.

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Interaction between the plume flow and the thermal boundary layer flow. From Xu et al. (2008).

Publications

  • Zhao, YL., Lei, C., Patterson, J.C. (2013) Resonance of the thermal boundary layer adjacent to an isothermally heated vertical surface. Journal of Fluid Mechanics (accepted 23 March 2013).
  • Zhao, YL., Hu, E., Blazewicz A. (2012). Dynamic modelling of the activated carbon-methanol adsorption refrigeration tube with considerations of interfacial convection and transient pressure process. Applied Energy. Doi:10.1016/j.apenergy.2012.02.050.
  • Zhao, YL., Hu, E., Blazewicz A. (2011) A comparison of three adsorption equations and sensitivity study of parameter uncertainty effects on adsorption refrigeration thermal performance estimation. Heat and Mass Transfer. Doi:10.1007/s00231-011-0875-8.
  • Zhao, YL., Hu, E., Blazewicz A. (2010) A non-uniform pressure and transient boundary condition based dynamic modeling of the adsorption process of an adsorption refrigeration tube. Applied Energy. Doi:10.1016/j.apenergy.2010.12.062.
  • Xu, F., Patterson, J.C. & Lei, C. (2009) Transient natural convection flows around a thin fin on the sidewall of a differentially heated cavity, Journal of Fluid Mechanics, 639, 261-290.
  • Xu, F., Patterson, J.C. & Lei, C. (2008) An experimental study of the unsteady thermal flow around a thin fin on a sidewall of a differentially heated cavity, International Journal of Heat and Fluid Flow, 29, 1139-1153.