ONE DIMENSIONAL MODEL TO PREDICT THE TOTAL PRESSURE LOSS OF VOLUTE FOR INWARD FLOW RADIAL SUPERCRITICAL CO2 TURBINES

Hoque, SJ and Kumar, P and Gopi, PC (2023) ONE DIMENSIONAL MODEL TO PREDICT THE TOTAL PRESSURE LOSS OF VOLUTE FOR INWARD FLOW RADIAL SUPERCRITICAL CO2 TURBINES. In: UNSPECIFIED.

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Abstract

Inward flow radial sCO2 turbines operate at considerably higher speeds than conventional gas or steam turbines making only the low specific speed designs practically realizable. Low specific speed designs suffer from significantly high viscous losses in the volute due to long and narrow flow passages. The volute loss in low specific speed designs causes an 8-12 efficiency drop, approximately 50 of the total loss. The paper proposes a quasi-one-dimensional model to estimate the total pressure loss of a volute with acceptable accuracy while consuming negligible computational power compared to a three-dimensional CFD simulation. The model converts the three-dimensional flow of a volute into an equivalent quasi-1D flow. Boundary layer-based momentum integral method is used on the quasi-1D flow path to calculate the total pressure loss. A computer program is developed to implement the proposed model. The accuracy of the model is tested with three-dimensional CFD results in the kW to MW power scale for different boundary conditions. The validation study is conducted for two volute cross-sections � circular and trapezoidal, to check the universality of the model. The model estimates the total pressure loss with less than 10 error for all test conditions. For the same conditions, a fully developed pipe flow model shows a considerably high error (~50) in total pressure loss prediction. The model can also accurately calculate losses under off-design operations and volute with surface roughness. Copyright © 2023 by ASME.

Item Type:	Conference Paper
Publication:	Proceedings of the ASME Turbo Expo
Publisher:	American Society of Mechanical Engineers (ASME)
Additional Information:	The copyright for this article belongs to American Society of Mechanical Engineers (ASME).
Keywords:	Carbon dioxide; Computational fluid dynamics; Steam turbines; Surface roughness, Loss model; Low specific-speed; One-dimensional model; Specific speed; Speed design; Supercritical CO 2; Supercritical CO2; Total-pressure loss; Vaneless; Vaneless turbine, Boundary layers
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	30 May 2024 05:44
Last Modified:	30 May 2024 05:44
URI:	https://eprints.iisc.ac.in/id/eprint/84298

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