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Corresponding Author

Mahgoub, Mohamed

Subject Area

Mechanical Power Engineering

Article Type

Original Study

Abstract

The present analysis investigates non-Darcy forced convective heat transfer in a cylindrical pipe filled with spherical beads saturated with non-Newtonian drag reducing fluid. The cylindrical pipe is subjected to either a uniform heat flux (UHF) or a constant wall temperature (CWT). In modeling the flow, both the energy equation and a modified momentum (Darcy-Forschheimer-Brinkman) equation are used , in which the variable porosity, flow inertia, Brinkman viscous friction (non-Darcian effects) besides the elongational viscosity of drag reducing fluids are taken into consideration and the finite difference technique is used. The results are obtained for a non-Newtonian drag parameter range of 0≤up≤5000, and nondimensional pressure gradient B up to 108. The results show that the non-Newtonian character of drag reducing fluids have a significant influence on the entrance length, beat transfer characteristics and the temperature profiles. Important results documenting and analyzing the behavior of the entrance length and the heat characteristics and its dependence on the non-Newtonian drag parameter are also reported. To examine the adequacy of the present heat transfer model. The governing equations were solved under conditions corresponding to those in Poulikakos and Renken [20]. The comparison of the calculated Nuf with that of Poulikakos and Renken[20]for d=3 and 5mm,up=0.0.05≤D≤0.15 and 104≤B≤106 shows good agreement and validates the presented heat transfer model.

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