Adaptive vaned diffuser for centrifugal compressor

Abstract Vaned diffusera are often preferred to a vaneless solution for improving maximum efficiency. The drawbacks of this choice are the reduction of stable working range and a narrower flow coefficient range at high efficiency. In this paper a solution to the above mentioned problems is presented. The solution proposed involves an adaptive varied diffuser: the vanes can be oriented in order to find the optimum incidence by means of a mechanism moved by an oleo-dynamic piston. Several sensor typologies have been tested to find which is the best to assess die actual flow angle. The aim is to correlate the optimum vane position with sensor output in order to provide a close-loop control system. An experimental analysis was carried out on an intermediate centrifugal compressor stage to validate this approach.