한국전산유체공학회:학술대회논문집
- 한국전산유체공학회 1999년도 춘계 학술대회논문집
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- Pages.192-198
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- 1999
수정점도 모델을 이용한 직사각형 덕트에서의 부력을 고려한 점탄성 유체의 열전달 특성
Heat Transfer Behavior of Viscoelastic Fluid including buoyancy effect with Modified Temperature Dependent Viscosity Model in a Rectangular Duct
초록
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 ail 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 gives under prediction than the existing temperature-dependent viscosity model in the regions of thermally developed with same secondary normal stress difference coefficients with experimental results in the regions of thermally developed. The heat transfer enhancement of the viscoelastic fluid in a 2:1 rectangular duct is highly dependent on the secondary flow caused by the magnitude of second normal stress difference.
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