Numerical investigation of partial admission losses in radial inflow turbines

Wang, Hanwei; Luo, Kai; Huang, Chuang; Zou, Aihong; Li, Daijin; Qin, Kan

doi:10.1016/j.energy.2021.121870

Cited by 4 publications

(1 citation statement)

References 41 publications

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“…Turbine efficiency should be calculated in each flow rate and pressure ratio. A most recent performance modelling of partial admission turbine is carried out in [28]. Their results were in good agreement with more than ten PA turbine models available in the literature.…”

Section: Partial Admission Turbinesupporting

confidence: 69%

Assessment of Organic Rankine Cycle Part-Load Performance as Gas Turbine Bottoming Cycle with Variable Area Nozzle Turbine Technology

Motamed

Nord

2021

Energies

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Power cycles on offshore oil and gas installations are expected to operate more at varied load conditions, especially when rapid growth in renewable energies puts them in a load-following operation. Part-load efficiency enhancement is advantageous since heat to power cycles suffer poor efficiency at part loads. The overall purpose of this article is to improve part-load efficiency in offshore combined cycles. Here, the organic Rankine bottoming cycle with a control strategy based on variable geometry turbine technology is studied to boost part-load efficiency. The Variable Area Nozzle turbine is selected to control cycle mass flow rate and pressure ratio independently. The design and performance of the proposed working strategy are assessed by an in-house developed tool. With the suggested solution, the part-load organic Rankine cycle efficiency is kept close to design value outperforming the other control strategies with sliding pressure, partial admission turbine, and throttling valve control operation. The combined cycle efficiency showed a clear improvement compared to the other strategies, resulting in 2.5 kilotons of annual carbon dioxide emission reduction per gas turbine unit. Compactness, autonomous operation, and acceptable technology readiness level for variable area nozzle turbines facilitate their application in offshore oil and gas installations.

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Section: Partial Admission Turbinesupporting

confidence: 69%

Assessment of Organic Rankine Cycle Part-Load Performance as Gas Turbine Bottoming Cycle with Variable Area Nozzle Turbine Technology

Motamed

Nord

2021

Energies

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Energy loss evaluation of a radial inflow turbine for organic Rankine cycle application using hierarchical entropy production method

Wang,

Yang,

et al. 2024

Physics of Fluids

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To evaluate the location and main sources of energy loss in radial inflow turbines for organic Rankine cycle application, this study proposed a hierarchical entropy production method, which is superior to the traditional pressure drop method. The method includes three levels: local entropy production, split of turbine total entropy production, and split of component entropy production. The energy loss of the radial inflow turbine under design condition and different pressure ratios is presented. The results indicate that the high-entropy production zone is primarily located at the stator trailing edge and the rotor tip clearance. The proportion of turbulent entropy production and wall entropy production in the total energy loss of the turbine is about 77% and 20%, respectively. Among the components of the radial inflow turbine, the energy loss of the rotor and diffuser is the highest, accounting for 71.9% and 13.6% of the total entropy production of the turbine, respectively. However, the stator and rotor have higher volume average entropy generation rate and area average entropy generation rate. The high-entropy production region is mainly located in the stator outlet zone and the rotor tip zone. When the pressure ratio increases from 3 to 5, the turbine efficiency decreases by 13.44%. The pressure ratio has a significant effect on the turbulent entropy production of the rotor. This method can provide insight into the energy loss characteristics of radial inflow turbines for organic Rankine cycle applications.

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Numerical and experimental investigation of irreversible energy losses in a two-stage radial turbine under asymmetric inflow conditions

Chen

Shi

2023

Proceedings of the Institution of Mechanical Engineers, Part D:

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In a two-stage turbocharger, the coupling between stages and the structure of the inter-stage duct may lead to severe flow distortions, which have a destructive impact on turbine performance. In this paper, the aerodynamics and energy loss mechanisms of two-stage turbines matched with a V-6 diesel engine are experimentally and numerically investigated. To reveal the formation mechanism of the asymmetric inter-stage flow, the vortex transportation in the high-pressure turbine is first analyzed. Entropy generation analysis is applied to quantify the irreversible losses while considering the coupling influence of the asymmetric inflow conditions, and two types of curved inter-stage ducts are studied. The sources of the dominant irreversible losses are revealed and origin of the corresponding energy loss is localized. The results show that the entropy generation rates associated with viscous dissipation, turbulent dissipation, and heat conduction account for about 30% each in the low-pressure turbine. Compared to uniform inflow conditions, the entropy generation rates increase by an average of 43.8%, 196.9%, and 19.2%, respectively under asymmetric inflow conditions. The pivotal turbulent dissipation is primarily concentrated in the inter-stage duct, the impeller inlet, and the volute tongue. The peak value for the difference in the cumulative entropy generation rates from turbulent dissipation is mainly caused by the mixing of the leakage vortex and the separation flow. The novelty of the present study lies in revealing the source of irreversible losses in two-stage turbines, which may provide a fundamental basis for the optimal design of a two-stage turbocharger.

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Numerical investigation of partial admission losses in radial inflow turbines

Cited by 4 publications

References 41 publications

Assessment of Organic Rankine Cycle Part-Load Performance as Gas Turbine Bottoming Cycle with Variable Area Nozzle Turbine Technology

Assessment of Organic Rankine Cycle Part-Load Performance as Gas Turbine Bottoming Cycle with Variable Area Nozzle Turbine Technology

Energy loss evaluation of a radial inflow turbine for organic Rankine cycle application using hierarchical entropy production method

Numerical and experimental investigation of irreversible energy losses in a two-stage radial turbine under asymmetric inflow conditions

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