INFLUENCE OF INJECTANT MACH NUMBER AND TEMPERATURE ON SUPERSONIC FILM-COOLING

Citation
Ka. Juhany et al., INFLUENCE OF INJECTANT MACH NUMBER AND TEMPERATURE ON SUPERSONIC FILM-COOLING, Journal of thermophysics and heat transfer, 8(1), 1994, pp. 59-67
Citations number
24
Categorie Soggetti
Engineering, Mechanical",Thermodynamics
ISSN journal
08878722
Volume
8
Issue
1
Year of publication
1994
Pages
59 - 67
Database
ISI
SICI code
0887-8722(1994)8:1<59:IOIMNA>2.0.ZU;2-C
Abstract
The current work is an experimental investigation of the dependence of film cooling effectiveness on the injection Mach number, velocity, an d mass flux. The freestream Mach number is 2.4, and the injection Mach numbers range from 1.2 to 2.2 for both air and helium injection. The adiabatic wall temperature is measured directly. The injection velocit y and mass nux are varied by changing the total temperature and Mach n umber while maintaining matched pressure conditions between the inject ed flow and that of the freestream. The total temperature of the frees tream is 295 K, and for the injection it ranges from 215-390 K. The re sults indicate an increase in film cooling effectiveness as the inject ion rate is increased. With the exception of heated helium runs, large r injection Mach numbers slightly increase the effective cooling lengt h per mass injection rate. The results for helium injection indicate a n increase in effectiveness as compared to that for air injection. Hea ted injection, with the injectant to freestream velocity ratios greate r than 1, exhibit a rise in wall temperature downstream of the slot re sulting in effectiveness values greater than 1. The experimental resul ts are also compared with earlier studies in the literature.