Loss Mechanism of Static Interstage Components of Multistage Centrifugal Compressors for Integrated Blade Design

Abstract

Although centrifugal compressors are widely used in construction, they consume a large amount of energy; in existing multistage centrifugal compressors, there is a serious pressure loss of ~15.13% when gas flows through the diffuser, bend, and return channel. In this study, we analyze the loss mechanisms of these stages in detail, using computational fluid dynamics. Based on this analysis, we present a new type of integrated blade, connecting the diffuser, bend, and return channels, which can eliminate the airflow stall phenomenon. Through effective control of the airflow spreading process, we minimized losses in the component, which improved its efficiency by 4.39% and increased the pressure ratio by 2.86% relative to a compressor without the newly-designed integrated blade. The concepts used in the creation of this component can provide a reference for the future design of blades for flow through parts of multistage compressors.

Influence of rotor–stator component partition structure on the aerodynamic performance of centrifugal compressors

“…Figure 5 shows the verification of a single-channel grid independence. These parameters did not change significantly when there were more than two million mesh elements (Ji et al, 2018). In all directions, the mesh met the calculation requirements for multiple grids, i.e.…”

“…We compared the computation results, using different turbulence models for a NACA model 404-III centrifugal compressor, to experimental data available in the literature (McKain & Holbrook, 1997). Figure 6 shows the results calculated using the Spalart-Allmaras model, which provided the closest match to the results of practical experiments (Ji et al, 2018). Figure 7 shows the distribution of y+ values on the solid wall.…”

“…Figure 7 shows the distribution of y+ values on the solid wall. Values of y+ < 10 are acceptable for the Spalart-Allmaras model to obtain valid conclusions (Ji et al, 2018). Spatial discretisation was performed using the space-centre differential format.…”

“…The wheel disk and cover sealing structures are identical, with six teeth. In this study, we investigated the intermediate stage of a vertical split type multistage centrifugal compressor with a closed impeller and 13 rear curved blades, followed by ten integrated stationary blades (Ji et al, 2018). Table 1 lists the geometric parameters and operating conditions.…”

“…CONTACT Chunyang Li 906549286@qq.com,lichunyang0807@dlut.edu.cn Flow channel design between the impeller and diffuser must consider two aspects. The first is radial clearance-if it is too long, the gas flow path is prolonged, thereby increasing friction loss; if it is too short, the rotor and stationary blades interfere with each other such that the wake of the impeller blade affects the uniformity of the inlet air flow at the stationary blade (Ji, Li, Fang, & Sun, 2018). Hosseini, Sun, He, and Zheng (2017) achieved a radial clearance ratio that yielded the best pressure recovery coefficient, loss coefficient, and grade efficiency when M u ≥ 1.…”