Volute-induced distortion of the flow field remarkably exacerbates the flow stability of turbocharger centrifugal compressors; hence, reducing the flow field distortion by modifying the volute design is of great significance. This study investigated the influence of volute design on the flow field distortion and flow stability of turbocharger centrifugal compressors. Volutes with different throat areas and different area-to-radius ratio ([Formula: see text]) distributions were designed, and their performances were analyzed via both numerical and experimental methods. The results show that the throat area and the [Formula: see text] distribution significantly influence the volute-induced pressure distortion. By modifying the volute design, the amplitude of the pressure distortion can be reduced from 8.82% to 3.22%, and the stable flow range can be extended from 49.8% to 58.7%. Additionally, to reduce flow field distortion, the throat area should be appropriate to guarantee a match between the volute and upstream components, and the [Formula: see text] distribution near the volute tongue should have a moderate slope. This study provides design methods for reducing flow field distortion by modifying the volute, and it also verifies the belief that smaller flow field distortion is beneficial to the flow stability of compressors.
The pipe diffuser, an efficient kind of radial bladed diffuser, is widely used in centrifugal compressors for gas turbine engines. This paper investigates flow characteristics of a pipe diffuser for centrifugal compressors by solving three-dimensional Reynolds-averaged Navier-Stokes equations. The results show that the pipe diffuser is adaptable to high Mach number incoming flows, and its unique leading edge could uniform the flow distortion. Numerical analysis indicates that the choke in pipe diffuser occurs suddenly, which leads to the dramatically steep performance curves near choke condition. Besides, it is found that the first half flow passage is particularly important to the pipe diffuser performance as it influences the choking behavior, the static pressure distribution, and the matching, so more attention should be paid to this region when designing or optimizing a pipe diffuser. Two counter-rotating vortices generated in the diffuser inlet region are captured by numerical simulation, and they can exist in the downstream of the diffuser passage. More detailed analysis show that these two vortices dominate the flow structure in the whole diffuser passage by shifting flow to certain positions and forming high-momentum flow cells and wake flow cells. The leading edge formed by the intersection of adjacent diffuser passages significantly affects this pair of vortices. In addition, these two vortices also affect the flow separation in pipe diffuser flow passages, they suppress separation near the front wall and back wall while facilitate separation at center locations. Therefore, it is recommended to design the leading edge of the pipe diffuser carefully to control the vortices and obtain a better flow field.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.