F101 LAMINAR HEAT AND FLUID FLOW CHARACTERISTIC INCLUDING BUOYANCY EFFECT WITH A MODIFIED TEMPERATURE-DEPENDENT VISCOSITY MODEL IN A RECTANGULAR DUCT(Heat transfer in complex system-1)

概要

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The present study proposes modified temperature-dependent non-Newtonian viscosity model and investigates flow characters and heat transfer enhancement of the viscoelastic non-Newtonian fluid in a 2:1 rectangular duct. The proposed modified temperature-dependent viscosity model has non-zero value near the high temperature and high shear rate region while on the existing viscosity models have zero value. Two versions of thermal boundary conditions involving difference combination of heated walls and adiabatic walls are analyzed in this study. The combined effect of temperature dependent viscosity, buoyancy, and secondary flow caused by second normal stress difference are all considered. The Reiner-Rivlin model is adopted as a viscoelastic fluid model to simulate the secondary flow caused by second normal stress difference. Calculated Nusselt numbers by the modified temperature-dependent viscosity model with the correct coefficient of second normal stress difference gave excellent agreement with experimental results in the regions of thermally developing and fully developed. The heat transfer enhancement of viscoelastic fluid in a 2: 1 rectangular duct is highly dependent on the secondary flow caused by the magnitude of second normal stress difference.
一般社団法人日本機械学会の論文
2000-10-01