EXPERIMENTAL STUDY ON ANALOGY PRINCIPLE OF OVERALL COOLING EFFECTIVENESS FOR COMPOSITE COOLING STRUCTURES WITH BOTH INTERNAL COOLING AND FILM COOLING

摘要

The previous theoretical work showed the matching principles of analogy parameters for effusion-impingement cooling model. The mismatch of temperature ratios T_g/T_c may result in different matching performance in laboratory condition. Thus, the analogy principles of overall cooling effectiveness were evaluated by experiments in different laboratory conditions for effusion-impingement cooling model. The film plate had 8 rows of cylinder film holes with staggered arrangement and the impingement holes was also employed staggered pattern. Four kinds of cases with different temperature ratios, varied from 1.1 to 2, were tested under three momentum flux ratios and corresponding blowing ratios. The 2D contours of overall cooling effectiveness were measured by using IR thermography. The results for cases with the same mainstream side Biot number and momentum flux ratio show similar contours and values of overall cooling effectiveness, although temperature ratios of these cases are different. And the maximum deviation of overall cooling effectiveness is within 0.02 for these cases. However, there were 0.04～0.08 difference in the overall cooling effectiveness when the blowing ratios were matched. The overall cooling effectiveness significantly decreases under each blowing ratios with the increase of temperature ratios.