Experimental Measurement of the Effect of Heat Flux on Local Heat Transfer Coefficient and Friction Coefficient in an Annulus
- 1 September 1965
- journal article
- Published by SAGE Publications in Journal of Mechanical Engineering Science
- Vol. 7 (3) , 300-305
- https://doi.org/10.1243/jmes_jour_1965_007_045_02
Abstract
This paper describes a closed-circuit apparatus for the measurement of local heat transfer coefficients from the inner surface and overall friction coefficients for air flowing through an annulus (radius ratio 1.7). Results were obtained for Reynolds numbers from 35 000 to 170 000 for temperature ratios Ti/Tb up to 1.74. A novel type of heater bar was used in order to avoid some of the disadvantages of the more usual designs. The results were very consistent. It was found that the effect of heat flux on the heat transfer coefficient could be eliminated either by the film temperature method using a film temperature coefficient of 0.25 or by including a temperature ratio term ( TiTb)-0.2 in the Nu-Re relationship. Over most of the Reynolds number range the overall friction coefficient did not vary with heat flux.Keywords
This publication has 1 reference indexed in Scilit:
- Heat transfer in annular passages—hydrodynamically developed turbulent flow with arbitrarily prescribed heat fluxInternational Journal of Heat and Mass Transfer, 1963