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18 pages, 3618 KiB

Open AccessArticle

A Study of Evaluation Method for Turbocharger Turbine Based on Joint Operation Curve

by Sheng Yin, Jimin Ni, Houchuan Fan, Xiuyong Shi and Rong Huang

Sustainability 2022, 14(16), 9952; https://doi.org/10.3390/su14169952 - 11 Aug 2022

Cited by 4 | Viewed by 2292

Turbochargers have evolved with the advancement of engine technology. In this study, we pro-posed a concept of joint operation, based on the operating characteristics of the compressor and turbine. Furthermore, a turbine evaluation method was proposed based on this concept, and an optimization application study of the turbine impeller blade number and turbine casing was con-ducted and verified. The results showed that the performance evaluation method based on the joint point could predict the optimization trend of turbine performance more accurately, the turbine output power optimized based on our new method evidently had advantages over the original turbine, and the joint point showed better overall performance. The original single-entry turbine could be optimized into a 9-blade twin-entry turbine having better response characteristics. The maximum torque of the optimized engine was 5.4% higher than that of the original engine, and the minimum brake specific fuel consumption (BSFC) was reduced by 2.1%. In the low and medium speed operating region, engine torque was increased by up to 3.2% and BSFC was reduced by up to 1.1% compared to the turbine optimized by conventional methods. Hence, the optimization effect of our new method was proven. Full article

(This article belongs to the Special Issue Emerging Research in Rotary Engines and Sustainability in Vehicle Engineering)

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17 pages, 8118 KiB

Open AccessArticle

Numerical Analysis of a Novel Twin-Impeller Centrifugal Compressor

by Van Thang Nguyen, Amélie Danlos, Florent Ravelet, Michael Deligant, Moises Solis, Sofiane Khelladi and Farid Bakir

Computation 2021, 9(12), 143; https://doi.org/10.3390/computation9120143 - 18 Dec 2021

Cited by 1 | Viewed by 6461

Abstract

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. Full article

(This article belongs to the Special Issue Computational Heat, Mass, and Momentum Transfer—III)

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22 pages, 9959 KiB

Open AccessArticle

Mechanisms of Sweep on the Performance of Transonic Centrifugal Compressor Impellers

by Xiao He and Xinqian Zheng

Appl. Sci. 2017, 7(10), 1081; https://doi.org/10.3390/app7101081 - 18 Oct 2017

Cited by 18 | Viewed by 10592

Abstract

Transonic centrifugal compressors with high performance are required in the oil and gas industries, modern gas turbine engines, and turbochargers. The sweep of the blades is one of the crucial features that have a significant influence on their performance. This paper numerically investigates mechanisms by which sweep affects the performance of a transonic impeller with twin splitters. Sweep is defined as scaling up or down the shroud chord, and the variation range of the sweep angle has been chosen from −25 to +25°. In the current case, results show that the variation of choke mass flow rate, pressure ratio, and efficiency value is around 1%. If the centrifugal compressor has a higher pressure ratio or a higher front loading, the sweep effect on compressor performance will be even stronger. The essential aerodynamic effect of sweep is the spanwise redistribution of the front loading, resulting in effects on the shock structure, the tip leakage vortex, and the flow separation. On the shroud section, forward sweep restricts the front loading, the shock strength, and the tip leakage vortex, which reduces the loss near the casing. On the hub section, aft sweep suppresses the front loading and the flow separation, which reduces the loss near the hub. It is the delicate balance between controlling the loss near the hub and the loss near the casing that determines the optimal sweep angle design. Full article

(This article belongs to the Section Mechanical Engineering)

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