EXPERIMENTAL STUDY OF FREE CONVECTION HEAT TRANSFER FROM AN INCLINED FINE WIRE TO AIR.

Average heat transfer coefficient of free convection from an inclined platinum wire of 50. 4 mu m in diameter and 270 mm in length to air has been measured in the range of temperature difference T//w minus T// infinity equals 17 to approximately 742 K. In the case where the wire is inclined at an angle phi (0 degree less than phi APP 1STH 85 degree ) to the horizontal, experimental data can be correlated by an expression which is derived by replacing gravitational acceleration g with g cos phi in the expression for a horizontal wire. In the case where the wire is inclined at an angle of a few degrees to the vertical, the data are scarcely affected by the inclination and can be correlated by the expression for a vertical wire. It is also confirmed that the effect of the magnitude of air space on heat transfer is negligible and the physical properties at the film temperature are adequate for use in the dimensionless expression.