Izvorni znanstveni članak
https://doi.org/10.15255/CABEQ.2016.1057
Heat Transfer at the Bottom of a Cylindrical Vessel Impinged by a Swirling Flow from an Impeller in a Draft Tube
K. Petera
orcid.org/0000-0002-8551-1904
; Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Process Engineering, Technicka 4, 16607 Prague, Czech Republic
M. Dostál
; Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Process Engineering, Technicka 4, 16607 Prague, Czech Republic
M. Věříšová
orcid.org/0000-0002-2587-7074
; Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Process Engineering, Technicka 4, 16607 Prague, Czech Republic
T. Jirout
; Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Process Engineering, Technicka 4, 16607 Prague, Czech Republic
Sažetak
Heat transfer at the bottom of a cylindrical vessel impinged by a flow with tangential velocity component generated by an axial-flow impeller in a draft tube was measured using the electrodiffusion experimental method. Local values of the Nusselt numbers along the radial coordinate of the heat transfer surface and corresponding mean values are presented for relatively small distances of the draft tube from the impinged surface (0.25 ≤ h / d ≤ 1). Such small distances are typical for mixing of liquids, which ensures good homogenization and increases the intensity of heat and mass transfer in many industrial operations. Results are compared with literature data for unconfined impinging jets with no tangential velocity components. The additional tangential velocity component generated by the rotating impeller significantly influences the hydrodynamics of the impinging jet and decreases the heat transfer intensity in the case of small distances from the impinged surface. A correlation describing the mean Nusselt number at the vessel bottom is proposed. It can be used in a design of a real industrial piece of equipment with heat transfer situated at the bottom.
This work is licensed under a Creative Commons Attribution 4.0 International License.
Ključne riječi
heat transfer; impinging jet; swirling flow; mixing vessel
Hrčak ID:
187148
URI
Datum izdavanja:
4.10.2017.
Posjeta: 1.364 *