Sharif Digital Repository

Erosive wear is one of the efficiency reduction causes in centrifugal compressors. The presence of suspended solid particles in the fluid causes deformations in different parts of the compressor, especially blades of the impeller. Therefore, erosion not only decreases the part lifetime by destruction of blades form, but also increases energy losses. For this reason, specifying the erosion locations and choosing a suitable material have an important effect on optimum functionality of the machine. In this paper, erosion locations of a compressor impeller by using computational fluid dynamics (CFD) in high temperature and pressure are attained and compared with experimental model. The... 

Efforts have been targeted at providing a comprehensive simulation of a centrifugal compressor undergoing surge. In the simulation process, an artificial neural network was utilized to produce an all-inclusive performance map encompassing those speeds not available in the provided curves. Two positive scenarios for the shaft speed, constant, and variable, were undertaken, and effects of load line on the dynamic response of the compressor have been studied. In order to achieve high-fidelity simulation in the variable speed case, an artificial neural network was utilized to produce an all-inclusive performance map encompassing those speeds not available in the provided curves. Moreover,... 

This paper describes a new quasi-3D design method for centrifugal compressor impeller. The method links up a novel inverse design algorithm, called Ball-Spine Algorithm (BSA), and a quasi-3D analysis. Euler equation is solved on the impeller meridional plane. The unknown boundaries (hub and shroud) of numerical domain are iteratively modified by BSA until a target pressure distribution in flow passage is reached. To validate the quasi-3D analysis code, existing compressor impeller is investigated experimentally. Comparison between the quasi-3D analysis and the experimental results shows good agreement. Also, a full 3D Navier-Stokes code is used to analyze the existing and designed compressor... 

In this article, the effects of volute cross section shape and centroid profile of a centrifugal compressor volute were investigated. The performance characteristics of a turbocharger compressor were obtained experimentally by measuring rotor speed and flow parameters at the inlet and outlet of the centrifugal compressor. The three dimensional flow field model of the compressor was obtained numerically solving Navier- Stokes equations with SST turbulence model. The compressor characteristic curves were plotted. For model verification, the results were compared with experimental data, showing good agreement. Modification of a volute was performed by introducing a shape factor for volute cross... 

Over the time, multistaging has proved to have some great benefits such as less electrical usage, so, nowadays; optimization of the electrical power usage in centrifugal compressors is an important issue to lead to the least usage of power. In this paper, we present a novel algorithm that provides this desire; it also shows different arrangement of the stages for the considered compressor. Simple single-stage compressor pressure ratio is normally limited by constraints of both aerodynamic and structural types. Reaching to minimum power leads to the least usage of electrical power. In this paper, we utilize theoretical relations which are extracted and have been presented a novel numerical... 

In this research, the centrifugal compressor of a turbocharger is investigated experimentally and numerically. Performance characteristics of the compressor were obtained experimentally by measurements of rotor speed and flow parameters at the inlet and outlet of the compressor. Three dimensional flow field in the impeller and diffuser was analyzed numerically using a full Navier-Stokes program with SST turbulence model. The performance characteristics of the compressor were obtained numerically, which were then compared with the experimental results. The comparison shows good agreement. Furthermore, the effect of area ratio and tip clearance on the performance parameters and flow field was... 

Design of centrifugal compressors can be accomplished using methods provided in text books and open literature. In this general approach, after determination of dimensions in meridional plane, blade profiles are designed using aerodynamic methods. Then, some blades are trimmed at the beginning to avoid inlet blockage. But there is no clear guidance on how this trimming must be performed. With this widely implemented method, splitter blades have the same profile as main ones. In this research, blade profiles and dimensions of the compressor impeller are not changed while the effect of changes in the position and angle of splitters leading edge are investigated. An optimization scheme is... 

In this research, multi-level optimization of the profile of the splitter blades of a turbocharger compressor is performed using genetic algorithm in order to improve its performance. Successive corrections of the profile at hub, mid-span, and shroud of the splitter blades, with the objective of decreasing the incidence losses at the leading edge and adjustment of the blade loading at the shroud, result in an impeller having improved splitter blades. The impeller flow field analysis shows that the optimization has been successful in reducing the flow leakage at the shroud region as well as the losses in the leading edge region. Although numerical simulations predict a decrease by 0.5% in...