Heated laminarizing gas flow in a square duct
| Autor: | K.R. Perkins, Donald M. McEligot, K.W. Schade |
|---|---|
| Rok vydání: | 1973 |
| Předmět: |
Fluid Flow and Transfer Processes
Materials science Adiabatic wall genetic structures Turbulence Mechanical Engineering chemistry.chemical_element Reynolds number Thermodynamics Laminar flow Mechanics Condensed Matter Physics Physics::Fluid Dynamics symbols.namesake chemistry Heat transfer Shear stress symbols Duct (flow) Helium |
| Zdroj: | International Journal of Heat and Mass Transfer. 16:897-916 |
| ISSN: | 0017-9310 |
| DOI: | 10.1016/0017-9310(73)90031-8 |
| Popis: | Experiments in a vertical, rounded-corner square duct are reported for heating rates which cause significant property variation in helium and nitrogen. New data are presented for adiabatic wall friction in laminar, transitional and turbulent flow and for heated flows in the low Reynolds number, turbulent range. The validity of an existing correlation for variable properties turbulent flow is extended down to Re i = 4000. In laminar flow, effects on local heat transfer parameters are slight but local friction factors vary strongly as the wall-to-bulk temperature ratio varies. Data concentrated in the range 3000 Re i 4 are examined to determine heating rates which cause premature laminarization as the Reynolds number decreases axially along the tube. Laminarization criteria based on inlet conditions correspond to values of the “critical” acceleration parameter observed for two-dimensional, accelerated, external flows. Local heat transfer measurements show a wall shear stress parameter provides a better indication of incipient laminarization along the duct than the acceleration parameter. |
| Databáze: | OpenAIRE |
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