Film cooling performance on pressure side of turbine blade with different number of hole rows under rotating state

Abstract

Film cooling is a major cooling method for turbine blades. Due to short film trajectories on the pressure side, the film coverage could be improved by increasing the number of hole rows. To study the effect of different hole rows on the film cooling performance of pressure side, this paper experimentally measures the film cooling effectiveness (η) of the pressure side with different number of hole rows (3, 4, and 5 rows) by employing pressure-sensitive paint (PSP) technology at a speed of 600 rpm. The effects of mass flow ratio (MFR), blowing ratio (BR), and hole arrangement (in-line and staggered) are analyzed. Numerical simulations are also performed for further analysis of the flow field. Under the mainstream parameters and blade structure in this study, the results show that: the three-row film hole cases have better film cooling performance at lower MFRs because of a larger film coverage; for four-row and five-row film hole cases, a belt region with poor film coverage appears at higher BRs, and the film cooling is influenced by the hole arrangement as well as behaves differently at lower and higher BRs.