An Experimental Investigation of the Transfer of Heat from Small Wires to a Viscous Compressible Fluid

Citation

Magnus, Richard Jeffrey (1955) An Experimental Investigation of the Transfer of Heat from Small Wires to a Viscous Compressible Fluid. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/4ZYH-PF56. https://resolver.caltech.edu/CaltechETD:etd-12042003-100200

Abstract

A steam tunnel, suitable for making experimental measurements of the heat transfer from fine wires to a viscous compressible fluid, was developed and constructed. Measurements of Nusselt numbers and recovery temperatures were carried out using small-diameter (0.00038 to 0.00254 cm.) tungsten wires in steam flow with Reynolds numbers ranging from about 1 to 12 and with nominal Mach numbers of 0.5 to 1.7. Considerable difference was found between the Nusselt numbers for wires in subsonic and supersonic flow at corresponding Reynolds numbers. The results could be fairly well represented by an available theory based on the assumption that a temperature discontinuity of the fluid existed at the wire surface; however, they did not agree very well with other available data in the same range of Mach and Reynolds numbers. In supersonic flow, the wire recovery temperatures were found to be consistently higher than the tunnel stagnation temperature. An experimental procedure for making end-loss corrections to the heat transfer and temperature recovery tests was used and found to give satisfactory correlation of data taken with wires ranging in aspect ratio from 220 to 3040. Some experiments were performed to check the validity of the simple linear theory which is usually used to calculate end loss corrections; the theory was found to be adequate in the experimental range covered.

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