Study of turbulent flow characteristics in a 180 degrees-bend annular diffuser with blowoff

An investigation of turbulent flows occurring in a 180 degrees-bend annular diffuser with an aperture in front of the bend is numerically and experime ntally conducted. The blowoff mass flow rate and the inlet pressure have be en systematically changed to study their influence on the diffuser performa nce. Results show that the pressure recovery coefficient increases with inc reasing blowoff mass flowrate and inlet pressure, but remains nearly consta nt if the inlet pressure is higher than about 10 bar. The numerical predict ions are compared with the experimental data and excellent agreement is ach ieved. The results provide insight into the characteristics of flow in the diffuser and are useful for diffuser designs of engineering interest. (C) 1 999 Elsevier Science Ltd.