Casing treatment is a mature stabilization technique which has been widely applied on aero-engines for modern aircrafts and turbo-chargers for automobiles. After the investigations of half century since the 1960 s, th...Casing treatment is a mature stabilization technique which has been widely applied on aero-engines for modern aircrafts and turbo-chargers for automobiles. After the investigations of half century since the 1960 s, this technique has been well developed for various configurations with different effectiveness. From the perspective of stabilization mechanism, this paper roughly categorizes the configurations of casing treatment into two types: traditional ones which work by affecting the flow structure of blade tip region; a novel one named as Stall Precursor-Suppressed(SPS) casing treatment. The effectiveness of both types will be demonstrated for their applications on axial compressors and centrifugal compressors with uniform or distorted inlet. And the stabilization mechanism of casing treatments for regular types and SPS one will also be explained respectively. In addition, this review will summarize the methodologies of casing treatments with the numerical simulations for regular grooved configurations and the eigenvalue approach for SPS casing treatment.Looking forward to the future of compressor stabilization, casing treatment technique will still exist as a general and inexpensive option, and the exploration for its effectiveness and mechanism will be deeper with the development of computational fluid dynamics and advanced measurement techniques.展开更多
Casing treatment is a widely employed technique to increase the stall margins of turbomachineries. In the last several decades, many researches on casing treatment have been carded out. However, the mechanism of its e...Casing treatment is a widely employed technique to increase the stall margins of turbomachineries. In the last several decades, many researches on casing treatment have been carded out. However, the mechanism of its expanding stall margins is still not very clear. Till now, most casing teatment schemes are designed for axial compressors, while the investigations on casing treatments in centrifugal compressors are rarely reported. Moreover, current investigation methods mainly focus on experiments, and perfect theoretic al analysis is not yet feasible. In order to study the effectiveness and further the mechanism of casing treatments in centrifugal compressors, in this paper, a computationally based investigation of the impact of the self-recireulating casing treatment on the performance of a radial compressor is carried out. The results indicate that, by casing bleed and injection, the casing treatment with inclined blades in the cavity expands the stall margin most. At low mass flows, the reversed flow through the cavity with inclined blades develops the counter swirl flow in front of the impeller inlet, which is considered to benefit increasing the pressure rise from the injection port to the bleed port and thereby augment the recirculating flow. At 120% design speed, the stall margin is larger than that at the design speed. However, the cost of extending the stall margin is the reduction of isentropic efficiency. A mended casing treatment by shifting the bleed port upstream is also studied. It is demonstrated that, relative to the original casing treatment, this mend can improve the efficiency evidently notwithstanding a little narrowing of the flow range.展开更多
The stall mechanism of the NASA Rotor 37 is investigated through the analysis of the critical flow structures near the stall under the transonic condition. The performance of the rotor with Circumferential Grooves Cas...The stall mechanism of the NASA Rotor 37 is investigated through the analysis of the critical flow structures near the stall under the transonic condition. The performance of the rotor with Circumferential Grooves Casing Treatment (CGCT) is also studied based on the Reynolds-Averaging Navier-Stokes approach. The study finds that stall margin improvement can be achieved without significant penalty on the efficiency for the two CGCT configurations applied. The effects of circumferential grooves on the critical flow structures are studied through the analysis of the tip leakage mass and momentum transport that further re-veal the CGCT mechanism.展开更多
The report describes the results of flow measurement within the flow passage of airseparator. It is important to effectively remove low energy fluid near the fan casing. It has been confirmed that the air-separator is...The report describes the results of flow measurement within the flow passage of airseparator. It is important to effectively remove low energy fluid near the fan casing. It has been confirmed that the air-separator is an excellent equipment for rotating stall suppression. Further, the air-separator improves the low flow rate range performance and increase stall margin of the axial flow fan.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 51790514, 11661141020 and 51576008)
文摘Casing treatment is a mature stabilization technique which has been widely applied on aero-engines for modern aircrafts and turbo-chargers for automobiles. After the investigations of half century since the 1960 s, this technique has been well developed for various configurations with different effectiveness. From the perspective of stabilization mechanism, this paper roughly categorizes the configurations of casing treatment into two types: traditional ones which work by affecting the flow structure of blade tip region; a novel one named as Stall Precursor-Suppressed(SPS) casing treatment. The effectiveness of both types will be demonstrated for their applications on axial compressors and centrifugal compressors with uniform or distorted inlet. And the stabilization mechanism of casing treatments for regular types and SPS one will also be explained respectively. In addition, this review will summarize the methodologies of casing treatments with the numerical simulations for regular grooved configurations and the eigenvalue approach for SPS casing treatment.Looking forward to the future of compressor stabilization, casing treatment technique will still exist as a general and inexpensive option, and the exploration for its effectiveness and mechanism will be deeper with the development of computational fluid dynamics and advanced measurement techniques.
基金supported by National Natural Science Foundation of China (Grant No. 50776056)National Hi-tech Research and Development Program of China (863 Program, Grant No. 2006AA05Z250)
文摘Casing treatment is a widely employed technique to increase the stall margins of turbomachineries. In the last several decades, many researches on casing treatment have been carded out. However, the mechanism of its expanding stall margins is still not very clear. Till now, most casing teatment schemes are designed for axial compressors, while the investigations on casing treatments in centrifugal compressors are rarely reported. Moreover, current investigation methods mainly focus on experiments, and perfect theoretic al analysis is not yet feasible. In order to study the effectiveness and further the mechanism of casing treatments in centrifugal compressors, in this paper, a computationally based investigation of the impact of the self-recireulating casing treatment on the performance of a radial compressor is carried out. The results indicate that, by casing bleed and injection, the casing treatment with inclined blades in the cavity expands the stall margin most. At low mass flows, the reversed flow through the cavity with inclined blades develops the counter swirl flow in front of the impeller inlet, which is considered to benefit increasing the pressure rise from the injection port to the bleed port and thereby augment the recirculating flow. At 120% design speed, the stall margin is larger than that at the design speed. However, the cost of extending the stall margin is the reduction of isentropic efficiency. A mended casing treatment by shifting the bleed port upstream is also studied. It is demonstrated that, relative to the original casing treatment, this mend can improve the efficiency evidently notwithstanding a little narrowing of the flow range.
基金supported by the GEA USA Programthe National Natural Science Foundation of China (Grant No.10477012)
文摘The stall mechanism of the NASA Rotor 37 is investigated through the analysis of the critical flow structures near the stall under the transonic condition. The performance of the rotor with Circumferential Grooves Casing Treatment (CGCT) is also studied based on the Reynolds-Averaging Navier-Stokes approach. The study finds that stall margin improvement can be achieved without significant penalty on the efficiency for the two CGCT configurations applied. The effects of circumferential grooves on the critical flow structures are studied through the analysis of the tip leakage mass and momentum transport that further re-veal the CGCT mechanism.
文摘The report describes the results of flow measurement within the flow passage of airseparator. It is important to effectively remove low energy fluid near the fan casing. It has been confirmed that the air-separator is an excellent equipment for rotating stall suppression. Further, the air-separator improves the low flow rate range performance and increase stall margin of the axial flow fan.
