Abstract:In many industries, reducing the size of the compression system represents a significant goal for designers. In fact, increasing the power density of the compressor actually means lowering production costs. The chief purpose of this study is to compare, in terms of aerodynamic performances, a centrifugal compressor consisting of an impeller and a volute, to an innovative concept based on the principle of two successive impellers and designed to work in counter-rotation. To simplify the experimental research in… Show more
“…The overall performance and geometric parameters of this CRCC configuration called CRCC2 can be found in Reference. 24 CRCC2 is completely different from CRCC1 as shown in Figures 5 and 6, but in this study, it uses the same spiral evolution section of the volute used for CRCC1 for a comparison purpose. That means CRCC2 uses the same RR outlet radius than that of CRCC1.Figure 5.Meridional shape comparison between CRCC1 and CRCC2.Figure 6.Second counter-rotating centrifugal compressor configuration: CRCC2.…”
The use of a counter-rotating rotor in turbomachines can be a solution to improve performances by allowing reduction in size and weight, especially compared to multistage configuration. The present study aims are to demonstrate another advantage of the counter-rotating rotors: their application to expand the operating range of centrifugal compressors toward extremely low flow rates based on an active control method. This method was performed on two different counter-rotating configurations. The principle of the active control method is to adjust independently the rotation speed of each rotor to push back the instability appearance. Experimental results show that reducing the rotation speed of the upstream-rotor while fixing the speed of the downstream rotor can push the instability phenomenon toward a lower mass flow rate while decreasing the pressure rise and efficiency. Co-rotating mode is applied to push further the stable region toward low mass flow rates allowing a significant extension of the operating range. The experimental results reveal that the map width is shifted by about 50% over the studied range toward a lower mass flow rate for both counter-rotating centrifugal compressors when using the control method. This can be achieved when the absolute value of the upstream-rotor speed is within the range of 48%–61% of the rotational speed of the downstream rotor.
“…The overall performance and geometric parameters of this CRCC configuration called CRCC2 can be found in Reference. 24 CRCC2 is completely different from CRCC1 as shown in Figures 5 and 6, but in this study, it uses the same spiral evolution section of the volute used for CRCC1 for a comparison purpose. That means CRCC2 uses the same RR outlet radius than that of CRCC1.Figure 5.Meridional shape comparison between CRCC1 and CRCC2.Figure 6.Second counter-rotating centrifugal compressor configuration: CRCC2.…”
The use of a counter-rotating rotor in turbomachines can be a solution to improve performances by allowing reduction in size and weight, especially compared to multistage configuration. The present study aims are to demonstrate another advantage of the counter-rotating rotors: their application to expand the operating range of centrifugal compressors toward extremely low flow rates based on an active control method. This method was performed on two different counter-rotating configurations. The principle of the active control method is to adjust independently the rotation speed of each rotor to push back the instability appearance. Experimental results show that reducing the rotation speed of the upstream-rotor while fixing the speed of the downstream rotor can push the instability phenomenon toward a lower mass flow rate while decreasing the pressure rise and efficiency. Co-rotating mode is applied to push further the stable region toward low mass flow rates allowing a significant extension of the operating range. The experimental results reveal that the map width is shifted by about 50% over the studied range toward a lower mass flow rate for both counter-rotating centrifugal compressors when using the control method. This can be achieved when the absolute value of the upstream-rotor speed is within the range of 48%–61% of the rotational speed of the downstream rotor.
“…The Twin-Impellers Centrifugal Compressor (TICC) has been realized in the laboratory of Fluid Engineering and Energy system (LIFSE) [11,12]. Figure 2 illustrates the test bench used to characterize the performance.…”
Section: Experiments Facilitiesmentioning
confidence: 99%
“…More details of these mesh sets are summarized in Table 4 and Figure 6. The simulation is performed at the speed N 1 = −11k rpm, N 2 = 11k rpm and is compared to the experimental results [11,12]. Figure 7 show the comparison between three performance curves corresponding to three mesh sets and the experimental data.…”
Section: Numerical Studymentioning
confidence: 99%
“…The geometry parameters of the upstream-impeller and downstream-impeller are summarized respectively in Tables 1 and 2. The first experimental results have been reported in refs [11,12]. The present paper is dedicated to the surge margin improvement is introduced by using the active control method.…”
Centrifugal compressors are widely used in many industrial fields such as automotive, aviation, aerospace. However, these turbomachines suffer instability phenomenon when the flow rate is too high or too low, called rotating stall and surge. These phenomena cause the operation failure, pressure fluctuations and vibrations of the thorough system. Numerous mechanical solutions have been presented to minimize these instabilities and expand the operating range towards low-flow rates like active control of the flow path, variable inlet guide vane and casing treatment. Currently, our team has developed a novel compressor composed of a twin-impeller powered by autonomous systems. We notice the performance improvement and instabilities suppression of this compressor experimentally. In this paper, an active control method is introduced by controlling the speed and rotation direction of the impellers to expand the operating range. A CFD study is then conducted to analysis flow morphology and thermodynamic characteristics based on the experimental observations at three special points. Numerical results and experimental measurements of compressor maps are consistent.
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