Heat transfer by natural convection from a horizontal isothermal circular cylinder in air

Journal Article · Wed Jan 01 04:00:00 EST 1997 · Heat Transfer Engineering

DOI:https://doi.org/10.1080/01457639708939887· OSTI ID:488938

Morgan, V T ^[1]

---

1. Commonwealth Scientific and Industrial Research Organization, Lindfield, New South Wales (Australia). Div. of Applied Physics

Because of its importance in industrial processes, overall natural convective heat transfer from horizontal cylinders has been the subject of many experimental and analytical studies. However, because of the dispersions in these results, there is still uncertainty about the value of the Nusselt number Nu at a particular Rayleigh number Ra, especially for Ra > 10{sup 3}. The values of Nu obtained from the most commonly used correlations do not reduce this uncertainty because of their own dispersion. To avoid the effect of higher Prandtl numbers Pr on the heat transfer, a review is made of the results from 34 experimental studies in air (Pr = 0.7) in the range 10 {le} Ra {le} 10{sup 7}. A review is also made of 23 analytical and numerical studies. It is concluded that the mean values of Nu within each of the two groups agree to within 4% in the range 10 {le} Ra {le} 10{sup 4}. At higher Ra, the mean of the experimental values of Nu is higher than the mean of the analytical and numerical values, the difference increasing from 7.86% at Ra = 10{sup 5} to 11.3% at Ra = 10{sup 7}. Possible reasons for this discrepancy are discussed.

• Sponsoring Organization: USDOE
• OSTI ID: 488938
• Journal Information: Heat Transfer Engineering, Journal Name: Heat Transfer Engineering Journal Issue: 1 Vol. 18; ISSN 0145-7632; ISSN HTEND2
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
AIR
CYLINDERS
NATURAL CONVECTION
NUSSELT NUMBER
ORIENTATION