Smart Nanomaterial Science

Micro/Nanoscale Thermal-Fluid Science

-

 Research Achievements:
 Micro/nanotechnology develops a large number of microfluidic and nanofluidic systems in silicon, quartz, glass, plastics, etc. The importance of micro/nanoflow arises from new applications in these system devices, such as microreactor hydrogenation-reaction conduction, microfuel cell transport (or other micropower sources), micropropulsion, microheat exchanging, and microchip cooling, etc. We initiated the studies of buoyancy-driven gas microflow (see Chen & Weng 2005 J. Heat Transf.-Trans. ASME 127, 1053) and thermocreep-driven gas microflow (see Weng & Chen 2008 Appl. Phys. Lett. 92, 094105). We also placed emphasis on the importance of thermal creep (see Chen & Weng 2006 J. Phys. D, 39, 3107, and Weng & Chen 2008 J. Phys. D, 41, 115501) and examined the roles of variable physical properties (see Weng & Chen 2008 J. Heat Transf.-Trans. ASME, 127, 1053) and wall-surface curvature (see Weng & Chen 2009 Int. J. Heat Mass Transfer 52, 1075). Recently, we found that based on the Navier-Stokes (NS) equations subject to the second-order slip boundary conditions, continuum modeling can be valid for the Knudsen numbers up to 1.60 (see Weng & Chen 2008 Phys. Fluids, 20, 106101). This means that NS-based second-order slip models may be used to analyze the gas transport phenomena in microfluidic devices in standard atmospheric conditions operate in the regimes for entire MEMS and μ-TAS applications. In addition, we provided a more detailed microscale theory of magnetogasdynamics (MGD) and developed a mathematical model of pressure-driven gas flow and heat transfer through a heated microchannel in the presence of an applied electric and magnetic field (see Weng & Chen 2013 Int. J. Heat Mass Transfer 57, 16).

Power and Energy Science



　

Illustration
　

˙Microfluidics•Nanofluidics
   – Nnanotubes

Material and systematic structures assembled from atoms or molecules with a size in the range of 1 to 100 nanometers are called nanostructures. A nanotube is a nanometer-scale tube-like structure.

˙Microfluidics•Nanofluidics
   – Magnetogasdynamic flow and heat transfer

To understand the causes of the two mechanisms and their roles on ionized gas microflow and heat transfer, a mathematical model was developed of the pressure-driven gas flow through a long isothermally heated horizontal planar microchannel under an applied electric and magnetic field. The fully developed solutions of the flow and thermal field distributions as well as the corresponding characteristics were then derived analytically and presented in terms of dimensionless parameters.