The paper describes a study of the effect of variations in the physical properties of a gas caused by large gas-to-wall temperature differences on the convective heat transfer to plain tubes in cross-flow.
The experiments were carried out in air at bulk air-to-wall temperature differences ranging from 109 K to 397 K with two levels of tube-wall temperature, 40°C or 120°C. The bulk Reynolds number ranged from 104 to 2.65 times 104.
It was found that the variation in physical properties could be accommodated by evaluating all of these properties in the dimensionless groups of the conventional type of correlation at the air bulk temperature.
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