Turbulent mixing enhancement with a 10 degrees chute mixer

Abstract

Purpose - Turbulent mixing of two co-axial jets having a low annular to core area ratio is enhanced by employing a chute mixer directing part of the annular stream at 10 degrees towards the core region. Aims to present results from measurements of time-averaged and fluctuating components of velocity under cold flow conditions, Design/methodology/approach - Experiments were conducted at a bypass ratio of 0.47 which is a typical value for low bypass turbofan engines. Contours of time-averaged velocity and streamwise and transverse turbulence intensities were obtained by making detailed measurements close to the chutes. Distributions of time-averaged velocity and turbulence intensity were obtained at different axial locations downstream of the chute mixer. Total and static pressure measurements were also performed. Findings - The high velocity annular stream was found to quickly diffuse after entering through the chutes and mix with the core stream due to high turbulence generation. A strong transverse turbulence component enhanced the mixing of the streams. With the aid of the chute mixer, nearly complete mixing is achieved over a length of 5 duct radii. A higher total pressure loss of about 1.38 percent is the penalty paid for the enhanced mixing. Originality/value - Provides results from experiments into the process of turbulent mixing of co-axial jets.