Effect of inlet ducts on the performance of a vaneless diffuser of a centrifugal compressor

Abstract

Dr. Basharat Salim Associate Professor ([email protected] ) Department of Mechanical Engineering College of Engineering, King Saud UniversityCentrifugal compressor is being used for in wide variety of industries. The impeller and diffuser form the basic components of a centrifugal compressor. The vaneless diffuser is primarily used for low or moderate pressure ratios and it provides wide operating range. Centrifugal compressor usually discharges non-uniform flow into the diffuser. This nature of exit flow from the impeller deteriorates the performance of the down stream vaneless diffuser. The development of the flow in a wide vaneless diffuser with a radial- bladed impeller upstream of it is the subject matter of this paper. The results are being reported in terms of variation of radial velocity, total pressure and flow angle along the radial path of the vaneless diffuser. The results are presented for the flow rate corresponding to maximum point of the characteristics of the compressor for three inlet duct shapes. Besides the performance parameters like static pressure rise coefficient, total pressure loss coefficient and pressure recovery coefficient for all these cases have also been presented. The results depict a strong dependence of vaneless performance and flow behavior on the inlet duct shapes and flow rate.Corresponding Author: Dr. Basharat Salim Associate Professor Department of Mechanical Engineering College of Engineering, King Saud University Riyadh, Saudi Arabia. Email: [email protected]