Sensitivity analysis and optimization of a CO2 centrifugal compressor impeller with a vaneless diffuser

Author(s):  
Leandro Oliveira Salviano ◽  
Elóy Esteves Gasparin ◽  
Vitor Cesar N. Mattos ◽  
Bruno Barbizan ◽  
Fábio Saltara ◽  
...  
Author(s):  
Kiyotaka Hiradate ◽  
Hiromi Kobayashi ◽  
Takahiro Nishioka

This study experimentally and numerically investigates the effect of application of curvilinear element blades to fully-shrouded centrifugal compressor impeller on the performance of centrifugal compressor stage. Design suction flow coefficient of compressor stage investigated in this study is 0.125. The design guidelines for the curvilinear element blades which had been previously developed was applied to line element blades of a reference conventional impeller and a new centrifugal compressor impeller with curvilinear element blades was designed. Numerical calculations and performance tests of two centrifugal compressor stages with the conventional impeller and the new one were conducted to investigate the effectiveness of application of the curvilinear element blades and compare the inner flowfield in details. Despite 0.5% deterioration of the impeller efficiency, it was confirmed from the performance test results that the compressor stage with the new impeller achieved 1.7% higher stage efficiency at the design point than that with the conventional one. Moreover, it was confirmed that the compressor stage with the new impeller achieved almost the same off-design performance as that of the conventional stage. From results of the numerical calculations and the experiments, it is considered that this efficiency improvement of the new stage was achieved by suppression of the secondary flows in the impeller due to application of negative tangential lean. The suppression of the secondary flows in the impeller achieved uniformalized flow distribution at the impeller outlet and increased the static pressure recovery coefficient in the vaneless diffuser. As a result, it is thought that the total pressure loss was reduced downstream of the vaneless diffuser outlet in the new stage.


1975 ◽  
Vol 97 (3) ◽  
pp. 337-345 ◽  
Author(s):  
D. Eckardt

One of the critical problems in centrifugal compressor design is the diffuser-impeller interaction. Up to now, theoretical models, which describe one of the salient features of this problem, the impeller discharge mixing process, appear to be proved experimentally only at low tip speeds. In the present study investigations on this subject were accomplished in the vaneless diffuser of a low-pressure ratio centrifugal compressor, running at tip speeds of 300 m/s. Detailed, instantaneous measurements in the impeller discharge mixing zone were performed by high-frequency measuring systems. Relative velocity distributions at the exit of impeller blade channels show pronounced jet/wake-patterns. The radial extension of flow distortions in the vaneless diffuser entry region, caused by rotating wakes, reached up to higher radius ratios than predicted by theoretical models.


Author(s):  
Hong-Won Kim ◽  
Seung-Hyup Ryu ◽  
Sang-Hak Ghal ◽  
Ji-Soo Ha

The centrifugal compressor design of the high-speed marine engine (500–900 kW) turbocharger has been done. Increased Higher compressed air and power density help improvement of the engine performance and power. The centrifugal compressor of the marine engine turbocharger is composed of impeller, 1st vaneless diffuser, vaned diffuser, 2nd vaneless diffuser and volute casing. The design process is achieved by three following stages. First, quasi-two dimensional code is used to determine the main geometry of the compressor. Second, three-dimensional compressible Navier-Stokes equation is applied to analyze the flow pattern and structures of the compressor blade loading. Here, among compressor impeller geometry, blade height variables are mainly changed. Smooth flow guidance has to precede and flow separation symptoms must not appear within compressor impeller. When the loading distribution is inadequate from blade hub to shroud, new curved profile should be designed to minimize the pressure loss. By analyzing the internal flow fields for the compressor impeller geometry variations, three dimensional impeller design profile has been confirmed. Compressed air pressure and mass flow rates from new optimized design were 2.7%, 27.3% higher than that of old one each other. Third, analyzed results are compared with experimental data for the verification of the present design method.


Author(s):  
N. Kämmer ◽  
M. Rautenberg

The flow through a centrifugal compressor impeller and a vaneless diffuser was investigated using unsteady pressure transducers and stationary probes when the compressor operated in the rotating stall region of the compressor map. The inlet velocity profile of the impeller was measured with traversing probes and was found to be significantly different from the profiles measured in an unthrottled condition. A zone of reverse flow was detected close to the suction duct wall as well as a strong swirl induced by the impeller. Circumferentially and meridionally spaced transducers made it possible to determine the stall frequency and the number of stall cells. The amplitude of the flow distortion as a function of meridional position was calculated from meridionally spaced transducers.


2007 ◽  
Vol 2007 (0) ◽  
pp. _G402-a_
Author(s):  
Ryota SUZUKI ◽  
Ken-ichiro IWAKIRI ◽  
Kei KUROITA ◽  
Masato FURUKAWA ◽  
Seiichi IBARAKI ◽  
...  

2007 ◽  
Vol 2007 (0) ◽  
pp. _G402-1_-_G402-4_
Author(s):  
Ryota SUZUKI ◽  
Ken-ichiro IWAKIRI ◽  
Kei KUROITA ◽  
Masato FURUKAWA ◽  
Seiichi IBARAKI ◽  
...  

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4292
Author(s):  
Kirill Kabalyk ◽  
Andrzej Jaeschke ◽  
Grzegorz Liśkiewicz ◽  
Michał Kulak ◽  
Tomasz Szydłowski ◽  
...  

The article describes an assessment of possible changes in constant fatigue life of a medium flow-coefficient centrifugal compressor impeller subject to operation at close-to-surge point. Some aspects of duct acoustics are additionally analyzed. The experimental measurements at partial load are presented and are primarily used for validation of unidirectionally coupled fluid-structural numerical model. The model is based on unsteady finite-volume fluid-flow simulations and on finite-element transient structural analysis. The validation is followed by the model implementation to replicate the industry-scale loads with reasonably higher rotational speed and suction pressure. The approach demonstrates satisfactory accuracy in prediction of stage performance and unsteady flow field in vaneless diffuser. The latter is deduced from signal analysis relying on continuous wavelet transformations. On the other hand, it is found that the aerodynamic incidence losses at close-to-surge point are underpredicted. The structural simulation generates considerable amounts of numerical noise, which has to be separated prior to evaluation of fluid-induced dynamic strain. The main source of disturbance is defined as a stationary region of static pressure drop caused by flow contraction at volute tongue and leading to first engine-order excitation in rotating frame of reference. Eventually, it is concluded that the amplitude of excitation is too low to lead to any additional fatigue.


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