상용 덕트 내에서의 Dilatant 유체를 이용한 압력강하 및 열전달 예측
Predictions of Pressure Drop and Heat Transfer in a Commercial Duct with Dilatant Fluids
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The prediction of pressure drop and heat transfer rate for the internal flow is a key to the problem of the commercial duct heat exchanger design. With a view to make such predictions for dilatant fluids, it is essential to first determine the relation between the viscous properties of such fluid and the wall shear rate in the duct. This study is confronted with the limits of validation of the power law equation. The effective approach of the present study involves a consideration of a more general constitutive equation which has Newtonian and power law behavior as asymptotes. The present numerical results of the product of friction factor and expanded Reynolds number for dilatant fluids in a circular duct are compared with previous literature values, presenting agreement with 0.03 % in Newtonian region and also 0.03 % in power law region. These dilatant fluid results also showed the 7% decrease of convective heat transfer rate compared with Newtonian heat transfer.
Abstract
The prediction of pressure drop and heat transfer rate for the internal flow is a key to the problem of the commercial duct heat exchanger design. With a view to make such predictions for dilatant fluids, it is essential to first determine the relation between the viscous properties of such fluid and the wall shear rate in the duct. This study is confronted with the limits of validation of the power law equation. The effective approach of the present study involves a consideration of a more general constitutive equation which has Newtonian and power law behavior as asymptotes. The present numerical results of the product of friction factor and expanded Reynolds number for dilatant fluids in a circular duct are compared with previous literature values, presenting agreement with 0.03 % in Newtonian region and also 0.03 % in power law region. These dilatant fluid results also showed the 7% decrease of convective heat transfer rate compared with Newtonian heat transfer.
참고문헌 (8)
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