Flow visualization studies on secondary flow patterns in straight tubes downstream of a 180 deg bend and in isothermally heated horizontal tubes
- Univ. of Alberta, Edmonton (Canada)
Photographs are presented for secondary flow patterns in a straight tube (x/d = 0 {approximately} 70) downstream of a 180 deg bend (tube inside diameter d = 2.54 cm, radius of curvature R{sub c} = 12.7 cm) and in an isothermally heated horizontal tube (tube inside diameter d = 2.54 cm, heated length 1 =46.2 cm) with free convection effects. Each test section is preceded by a long entrance length with air as the flowing fluid. For curved pipes, the Dean number range is K = 99 to 384. At the exit of the 180 deg bend, the onset of centrifugal instability in the form of an additional pair of Dean vortices near the central outer wall occurs at a Dean number of about K = 100. The developing secondary flow patterns in the thermal entrance region of an isothermally heated horizontal tube are shown for the dimensionless axial distance z = 0.8 {times} 10{sup {minus}2} to 1.83 (Re = 3,134 {approximately} 14) for a range of constant wall temperatures T{sub w} = 55 {approximately} 65C with entrance air temperature at about 25C. The secondary flow patterns shown are useful for future comparisons with predictions from numerical solutions.
- OSTI ID:
- 5345131
- Journal Information:
- Journal of Heat Transfer (Transcations of the ASME (American Society of Mechanical Engineers), Series C); (United States), Journal Name: Journal of Heat Transfer (Transcations of the ASME (American Society of Mechanical Engineers), Series C); (United States) Vol. 109:1; ISSN 0022-1481; ISSN JHTRA
- Country of Publication:
- United States
- Language:
- English
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