Forced convection heat transfer at an inclined and yawed round tube

Experiments have been performed to determine the heat transfer coefficients for forced convection airflow over a cylindrical obstacle that is inclined and yawed relative to the oncoming flow. The experiments encompassed a wide range of angles of attack and angles of yaw, and extended over a Reynolds number ranging from about 1000 to 7000. It was found that owing to three-dimensional flow effects, the heat transfer coefficients were remarkably insensitive to both the angle of attack and the angle of yaw. This enabled all the results to be correlated by the equation Nu(Z)=0.182Re0.63Pr1/3 with an accuracy of ±4%. This investigation also introduces a factor (Cθ=Nu(Z)/Nu(Z)θ=90°) which can be used for finding the heat transfer on a tube positioned at different angles to the flow direction. No perceptible dependence of Cθ on Re was detected. In addition, flow visualizations were explored to broaden our fundamental understanding of the heat transfer outside the tube.