Heat transfer by forced convection from a cylinder to water in crossflow

Abstract

This paper presents the results of an experimental investigation of heat transfer by forced convection from a cylinder to water in crossflow in the range of Reynolds numbers from approximately 10 4 to 10 5. The diameter of the test cylinder was 0.4375 in, and the temperature difference varied from 4 to 10 degF. The experimental data are in close agreement (mean deviation = 1 per cent) with the McAdams correlation, namely, (Nu) f=[0.35+0.56(Re) f 0.52](Pr) f 0.30 . McAdams derived his correlation equation from experimental data taken in the limited range of crossflow Reynolds numbers from 10 −1 to 2 × 10 2. Purves and Brodkey infer from the Colburn analogy that McAdams' correlation is valid in the range of Reynolds number from 10 2 to 10 4. Therefore, on the basis of the present experimental data, it is concluded that McAdams' equation is valid in the extended range of Reynolds numbers from 10 −1to 10 5. The present experimental data are equally well represented by (Nu) f=[0.35+0.34(Re) f 0.50+0.15(Re) f 0.58](Pr) f 0.30 . In the latter equation, the term in ( Re) f 0.50 represents the heat transfer through the laminar boundary layer on the front portion of the cylinder, and the term in ( Re) f 0.58 accounts for the contribution to the total heat transfer from the back portion of the cylinder, where separation occurs. Either of the two equations given here may be used for design calculations, but the second equation is preferable in the the sense that it is more logically related to the physical processes involved.