of Professor Guihua Tang- 9.05.2014, room 200, Institute of Mechanics
Общоинститутски семинар № 1
9 May 2014 г, 14:00 , Hall 200, Institute of Mechanics
Title: Thermal Conductivity of Nano-Porous Insulation Materials
Lecturer: Professor Guihua Tang (Department of Thermo-Fluid Science and Engineering
School of Energy and Power Engineering, Xi'an Jiaotong University, P.R.China)
Abstract: Aerogel is a typical nano-porous material, with a three-dimensional network of backbone composed of interconnected solid nano-particles, which is able to suppress heat transfer through gas filled in the porous and solid backbone and radiation as well, resulting in excellent thermal insulation performance. Firstly, we present a modified model based on the pore size distribution to predict the gaseous thermal conductivity. Secondly, we present a model to predict the phonon mean free path and effective thermal conductivity of the aerogel solid backbone and also discuss the size effect and interfacial resistance. Thirdly, a Monte Carlo Ray Tracing method is developed to determine the radiative properties of nano-porous media. The simulations are conducted in three dimensional skeleton structure of nano-porous media made up of randomly packing of equal sized spheres, and the absorption and scattering coefficients of the sphere are calculated by Rayleigh-scattering. In addition, the thermal conductivity of silica aerogels doped with carbon black is investigated to reduce radiative heat transfer at high temperature. Finally, the thermal conductivity in porous thin film, which is of significant application in thermoelectrics, is numerically investigated by the Discrete Ordinate Method and the synergy angle between heat fluxes is proposed to optimize the thermal conductivity.
Guihua Tang (GH Tang) is a full Professor, Deputy Head of the Department of Thermo-Fluid Science and Engineering in the School of Energy and Power Engineering at Xi'an Jiaotong University, China. He worked as a Higher Scientific Officer in the UK STFC Daresbury Laboratory from April 2007 to August 2009. He also worked as a visiting scholar at University of Strathclyde March-August 2008, July-August 2013 and January-March 2014. His main research covers thermal transport in nanoscale porous materials, non-Newtonian liquid flow and non-equilibrium gas flow in microchannels and micro-porous media, and the lattice Boltzmann method. He has published over 50 peer-reviewed journal papers and authorised three China Invention Patents. He was invited to organize six international conference sessions or mini-symposiums. He was also on the organizing committee of three international conferences. He is an Editorial Board member of four international Journals and serves as reviewer for more than 50 international journals. Currently, he is the PI for several major research projects on fluid flow and heat transfer funded by the National Natural Science Foundation of China (NSFC) and National Basic Research Program of China (973 Program).