Radial turbine optimization under unsteady flow using nature-inspired algorithms

Mehrnia, Seyedmajid; Miyagawa, Kazuyoshi; Kusaka, Jin; Nakamura, Yohei

doi:10.1016/j.ast.2020.105903

Cited by 16 publications

(8 citation statements)

References 25 publications

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“…Figure17 presents the unsteady performance in term of expansion ratio versus the mass flow rate superimposed to that of the steady state. The unsteady swallowing capacity of the twin-entry radial turbine exhibits a large hysteresis-loop similar to that obtained experimentally by Dale and Watson [9] and Winterbone et al [46].This hysteresis behavior is attributed to the mass flow continuously filling and emptying the two volutes volumes during the transient periods. The mass flow imbalance between the inlet and outlet flows and during the pulses occurs as explained by Chen et al [47], Karamanis, and Martinez-Botas [48].In Fig.…”

Section: Iv2 Transient Performance Of Twin-entry Radial Turbinesupporting

confidence: 81%

Matching of Radial Inflow Turbines with Internal Combustion Engines Considering Pulsating Flows

CERDOUN,

Ghenaiet,

Ferrara

2023

Preprint

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This paper investigates numerically the effects of pulsating exhaust gases on the operations of radial inflow turbines and their matching with internal combustion engines at full-load conditions. Both single- and twin-entry radial turbines are considered and the transient behaviors are analyzed by combining the CFD and analytical models. As results, the unsteady performances are shown to deviate noticeably from the steady state due to high levels of unsteadiness of the inlet conditions. A typical hysteresis-loop relating the effect of gas filling-emptying inside the volute is well depicted. Unsteady performance of the twin-entry radial turbine depicts that the of hysteresis-loop is wide due to large volute volume whereas the hysteresis-loop of single-entry turbine seems reducingas the amplitude of pressure pulse reduces. For the compressor side of the twin-entry radial turbine, and depending on the engine speed, the average values of unsteady performances exhibit deviations up to 9% in pressure ratio and 7.8% in airflow swallowing capacity, in contrast to the single-entry radial turbine these deviations are lesser about 4 and 4.9%, respectively. These differences could be related to the two sides of volute which are source of hysteresis and flow interaction.

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Section: Iv2 Transient Performance Of Twin-entry Radial Turbinesupporting

confidence: 81%

Matching of Radial Inflow Turbines with Internal Combustion Engines Considering Pulsating Flows

CERDOUN,

Ghenaiet,

Ferrara

2023

Preprint

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“…The shear stress transport (SST) model is used to model the turbulence flow, which used in many turbomachinery applications found in the literature. 29,30 This model combines the advantages of the robustness of K-Omega model and the insensitivity of inlet turbulence parameters of K-Epsilon model, so that the flow separation in the turbine can be simulated precisely. The near wall boundary condition, named automatic near wall treatment in CFX, was used as the default in shear stress turbulence (SST) model.…”

Section: Cfd Studymentioning

confidence: 99%

“…Seyedmajid Mehrnia et al 5 investigated the performance of a radial turbine by coupling metaheuristic algorithms with Computational Fluid Dynamics. Rongchao Zhao et al 6 investigated the characterization of two-stage turbine system under steady and pulsating flow conditions by numerical method. However, experimental validation data are still required to ensure that CFD predicted flow physics are credible with the flow physics in real world.…”

Section: Introductionmentioning

confidence: 99%

Experimental approach of surface pressure measurements on additive manufactured nozzle guide vane in a turbocharger turbine

Wang

Zhu

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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Obtaining the surface pressure measurement of the pneumatic blades in turbomachinery is beneficial in understanding the flow mechanism around the blades and designing of the blades to improve the turbomachinery performance. However, it is difficult for the turbocharger turbine due to the space limitation, high rotational speed, and small geometric size. The present study investigates a novel measuring approach of the surface pressure of the guide vane in a turbocharger turbine based on the additive manufacturing techniques, which is not reported in the previous literature. The static pressure on the pressure side and suction side of the guide vanes in the variable nozzle turbine was investigated using both the experimental and numerical methods. The results show that the majority of the measuring results generally agree with the numerical prediction at different operating points with the relative difference below 5%. Besides, the trends of the static pressure as the rotational speed and mass flow rate between the pressure side and suction side were also captured in the experimental methodology. The highest deviations between experimental and calculated models were found in the first and fifth pressure taps on the guide vanes with an averaged absolute relative difference of up to 11.61% and 16.1% for 20% opening and 60% opening, respectively. The ratio of the kinetic pressure to total pressure and the flow field in the guide vane passage were analyzed to estimate the influence on the static pressure measurement. Nevertheless, the preliminary comparison results still encourage and extend the bounds of the possibility in the use of additive manufacturing techniques for miniature pneumatic blade surface pressure measurement.

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“…Uniform distribution over the 360 degrees of the radial stator is important to then adapt the flow at the rotor inlet, a matter of interest in [22], where they tested flow behavior for twin-entry turbines as two separated single VGT volutes. Therefore, while some authors focus on a volute casing optimization, as in [23], the stator and its vanes must be designed according to an aerodynamic geometry that has the least possible amount of energy losses [24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Numerical Evaluation in a Scaled Rotor-Less Nozzle Vaned Radial Turbine Model under Variable Geometry Conditions

et al. 2022

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The widespread trend of pursuing higher efficiencies in radial turbochargers led to the prompting of this work. A 3D-printed model of the static parts of a radial variable geometry turbine, the vaned nozzle, and the volute, was developed. This model was up-scaled from the actual reference turbine to place sensors and characterize the flow around the nozzle vanes, including the tip gap. In this study, a computational model of the scaled-up turbine was carried out to verify the results in two ways. For this model, firstly compared with an already validated CFD turbine model of the real device (which includes a rotor), its operating range was extended to different nozzle positions, and we checked the issues with rotor–stator interactions as well as the influence of elements such as the screws of the turbine stator. After showing results for different nozzle openings, another purpose of the study was to check the effect of varying the clearance over the tip of the stator vanes on the tip leakage flow since the 3D-printed model has variable gap height configurations.

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Radial turbine optimization under unsteady flow using nature-inspired algorithms

Cited by 16 publications

References 25 publications

Matching of Radial Inflow Turbines with Internal Combustion Engines Considering Pulsating Flows

Matching of Radial Inflow Turbines with Internal Combustion Engines Considering Pulsating Flows

Experimental approach of surface pressure measurements on additive manufactured nozzle guide vane in a turbocharger turbine

Numerical Evaluation in a Scaled Rotor-Less Nozzle Vaned Radial Turbine Model under Variable Geometry Conditions

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