Combined forced and free laminar convection in the entrance region of an inclined isothermal tube

Journal Article · Tue Nov 01 00:00:00 EST 1988 · Journal of Heat Transfer (Transcations of the ASME (American Society of Mechanical Engineers), Series C); (United States)

DOI:https://doi.org/10.1115/1.3250591· OSTI ID:5465215

Choudhury, D; Patankar, S V ^[1]

---

1. Univ. of Minnesota, Minneapolis (USA)

An analysis is made of the combined forced and free convection for laminar flow in the entrance region of isothermal, inclined tubes. This involves the numerical calculation of the developing flow with significant buoyancy effects. Three independent parameters are introduced: the Prandtl number Pr, a modified Rayleigh number Ra*, and {Omega}, a parameter that measures the relative importance of free and forced convection. The inclination angle does not appear explicitly in the formulation. Numerical results are obtained for Pr = 0.7, 5, and 10, and representative values of Ra* and {Omega}. The axial development of the velocity profiles, temperature field, local pressure gradient, and the Nusselt number are presented. These results reveal that the buoyancy effects have a considerable influence on the fluid flow and heat transfer characteristics of the development flow. A comparison of the numerical results with the available experimental data is also presented.

• OSTI ID: 5465215
• Journal Information: Journal of Heat Transfer (Transcations of the ASME (American Society of Mechanical Engineers), Series C); (United States), Vol. 110:4A; ISSN 0022-1481
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
TUBES
FORCED CONVECTION
NATURAL CONVECTION
CALCULATION METHODS
LAMINAR FLOW
NUSSELT NUMBER
ORIENTATION
PRANDTL NUMBER
PRESSURE GRADIENTS
RAYLEIGH-TAYLOR INSTABILITY
TEMPERATURE GRADIENTS
VELOCITY
CONVECTION
ENERGY TRANSFER
FLUID FLOW
HEAT TRANSFER
INSTABILITY
MASS TRANSFER
420400* - Engineering- Heat Transfer & Fluid Flow