A reduced-order model of twin-entry nozzleless radial turbine based on flow characteristics

Wei, Jiao; Xue, Yingxian; Yang, Mingyang; Deng, Kangyao; Wang, Cuicui; Wu, Xin‐Tao

doi:10.1016/j.energy.2020.118890

Cited by 6 publications

(3 citation statements)

References 15 publications

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“…Recently Wei et al 32 studied a nozzleless twin-entry turbine, and they found that the efficiency of the hub side partial admission is lower than the shroud side partial admission at low velocity ratio conditions, but higher at high velocity ratio conditions. For the twin-entry turbine in this study, the efficiency is higher when the shroud side inlet flows more at the low and medium speeds but is lower at the high speed.…”

Section: Resultsmentioning

confidence: 99%

A two-dimensional method for radial turbine volute design

Wang

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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In this work, a new two-dimensional method is presented for turbine volute design. In this method, the continuity equation, energy equation, free vortex equation, and streamline equation are employed to solve the velocity field and to generate the volute profile. The physical model and mathematic solution to the governing equations are described in detail. A new volute for a turbocharger turbine is generated using this method and compared with the original, well-designed baseline volute. Different turbine operating conditions, including equal and unequal admission cases, were studied by CFD to compare turbine aerodynamic performance using the new and baseline volutes. The simulation results show that the efficiency of the new volute is about 0.4%–0.6% higher than the baseline under equal admission conditions. It is found that the improvement in turbine performance is mainly due to the more reasonable A/R distribution, which reduces the losses in the turbine. This work demonstrates that the proposed new method provides an effective way for radial turbine volute design, and can quickly create high performance volutes.

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Section: Resultsmentioning

confidence: 99%

A two-dimensional method for radial turbine volute design

Wang

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…Therefore, the flow distortion should also be taken into consideration to establish a meanline model of twin-entry turbine, and cannot be captured with only one flow passage downstream of the volute. Wei et al 17 developed a meanline model of twin-entry nozzleless turbine referring to 'parallel rotor' model. Rotor is divided into four parts to simulate flow distortion in spanwise and circumferential directions.…”

Section: Introductionmentioning

confidence: 99%

Study on a flow-field-based meanline model of nozzled twin-entry mix-flow turbine

Xue

Yang

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part D:

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Variable geometry twin-entry turbine has advantages in fuel economy, low-end torque, emission and turbo-engine matching of internal combustion engine. The reliability of performance prediction method for nozzled twin-entry turbine is heavily dependent on the understanding of flow mechanism of the turbine which is always confronted by time-dependent unequal admissions. This paper establishes a new meanline model of a nozzled twin-entry turbine based on the internal flow features. Firstly, flow mechanism of the twin-entry turbine with a vaned nozzle under different admissions is investigated via an experimentally validated CFD method. Results clearly demonstrate that the flow distortion in spanwise direction caused by unequal admissions notably influences the turbine efficiency discrepancy between symmetric unequal admissions, especially the two partial admissions. The evolution of flow distortion in the nozzle passage is the key to the performance discrepancy, which is impossible to be considered by a conventional performance model of a nozzled twin-entry turbine. Inspired by this, a newly-designed meanline model, named ‘parallel nozzle’ is proposed. Specifically, a nozzle passage is divided into two parallel sub-passages in spanwise direction to consider the flow distortion in nozzle passage. The model is validated against the detailed CFD results in terms of both overall performance and detailed flow parameters over different admissions. Results prove that turbine performance and flow parameters are well predicted by the model. Specifically, the influence of admissions on nozzled twin-entry turbine performance and flow parameters can be predicted by the method in satisfying accuracy.

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“…The Authors developed a validated CFD model in order to perform an in-depth analysis of the different contribution of losses in the twin entry turbine; the greatest performance is obtained when the rotor is fed from the shroud side thanks to the removal of the tornado vortex. Wei et al [13] developed a reduced-order model of a twin entry turbine capable of capturing the influence of flow distortion, due to partial and unbalanced admission, on turbine rotor performance. Cravero et al [14] developed a complete CFD model of a twin scroll radial turbine and perform simulations in full and partial admission to contribute to the literature in the understanding of this turbomachinery; moreover, they proposed several performance indices for optimization purposes.…”

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confidence: 99%

Steady State Experimental Characterization of a Twin Entry Turbine under Different Admission Conditions

Usai

Marelli

2021

Energies

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The increasingly restrictive limits on exhaust emissions of automotive internal combustion engines imposed in recent years are pushing OEMs to seek new solutions to improve powertrain efficiency. Despite the increase in electric and hybrid powertrains, the turbocharging technique is still one of the most adopted solution in automotive internal combustion engines to achieve good efficiency with high specific power levels. Nowadays, turbocharged downsized engines are the most common solution to lower CO2 emissions. Pulse turbocharging is the most common boosting layout in automotive applications as the best response in terms of time-to-boost and exhaust energy extraction. In a high-fractionated engine with four or more cylinders, a twin entry turbine can be adopted to maximize pulse turbocharging benefits and avoid interaction in the discharge phase of the cylinders. The disadvantages of the twin entry turbine are mainly due to the complexity of the exhaust piping line and the high amount of information required to build a rigorous and reliable matching model. This paper presents a detailed experimental characterization of a twin entry turbine with particular reference to the turbine efficiency and the swallowing capacity under different admission conditions. The steady flow experimental campaign was performed at the turbocharger test bench of the University of Genoa, in order to analyze the behavior of the twin entry turbine in full, partial and unbalanced admission. These are the conditions in which the turbine must work instantaneously during its normal operation in engine application. The results show a different swallowing capacity of each sector and the interactions between the two entries.

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A reduced-order model of twin-entry nozzleless radial turbine based on flow characteristics

Cited by 6 publications

References 15 publications

A two-dimensional method for radial turbine volute design

A two-dimensional method for radial turbine volute design

Study on a flow-field-based meanline model of nozzled twin-entry mix-flow turbine

Steady State Experimental Characterization of a Twin Entry Turbine under Different Admission Conditions

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