Library Subscription: Guest

ISSN Online: 2377-424X

ISBN Print: 0-89116-130-9

International Heat Transfer Conference 6
August, 7-11, 1978, Toronto, Canada

EFFECT OF INTERACTION BETWEEN AXIALLY AND RADIALLY FLOWING COOLANT ON THE FILM COOLING EFFECTIVENESS OF A TUBE WALL

Get access (open in a dialog) DOI: 10.1615/IHTC6.1300
pages 273-278

Abstract

In extensive experiments cold air was injected tangentially through an annular slot into a fully developed and turbulent hot air pipe flow. At a distance downstream additional coolant was introduced through radial holes, arranged circumferentially in two rows. Thus a continous radial slot could be approximated. Measurements have been performed of the adiabatic wall temperature distribution of the test section downstream from the points of injection as a function of the velocity ratios of the slotstream to the mainstream and of the holestream to the mainstream.
In general the interaction of slot and hole injection improves film-cooling. The cooling effectiveness downstream of the holes revealed a strong dependence on the mass velocity of the slotstream and of the holestream and on the distance between the slot and the hole arrangement.
In contrast to the hole arrangement in rows, discrete holes don't improve or even deteriorate cooling effectiveness when interacting with a tangential slotstream.
Based upon the experiments the cooling effectiveness n can be correlated as a function of the mass flow rates, the velocities, the densities and the specific heat capacities of the three streams as well as a function of the distance between the injection locations. The correlation is in good agreement with the experimental data.