Theoretical and experimental investigation of design parameter effects on the slip phenomenon and performance of a centrifugal compressor

There are many pieces of research considering slip phenomenon in centrifugal compressors to drive equations for prediction of the slip factor. Inevitably, some simplifications have been imposed on the flow field characteristics and effects of many parameters have been neglected. In this research slip phenomenon is investigated experimentally and numerically in one centrifugal compressor with complex blade curves and splitter blades considering the main effective parameters. Three-dimensional simulation of the compressor viscus flow field with suitable turbulence method was performed using CFD methods. Experimental work was carried out at several rotational speeds and mass flow rates which enabled slip factor results of the compressor as well as, approving accuracy of the simulation results. Effect of main parameters such as rotational speed, mass flow rate, blade number, blade exit angle, diffuser design and tip clearance on slip phenomenon were studied. It was observed that slip factor increases, as rotational speed and flow rate increase. Also changing the blade number from 6 to 9 in constant rotational speed and mass flow rate, caused 27 percent increase in slip factor. For a detailed insight, a variation of performance parameters such as pressure ratio and isentropic efficiency with slip factor were investigated, as well.