A comparison of axial turbine loss models for air, sCO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="d1e3771" altimg="si141.svg"><mml:msub><mml:mrow/><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math> and ORC turbines across a range of scales

Salah, Salma I.; White, Martin T.; Sayma, A. I.

doi:10.1016/j.ijft.2022.100156

Cited by 20 publications

(9 citation statements)

References 27 publications

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“…An in-house mean line design tool is used to develop the turbine flow path [24,25]. Within the tool, the steady-state mass, energy, and momentum equations are solved to obtain the blade geometry, velocity triangles, and thermodynamic properties for all turbine stages.…”

Section: Meanline Design Modelmentioning

confidence: 99%

“…The thermodynamic properties and velocity triangles can be obtained at each boundary for both the stator and rotor, as defined in Figure 1. Following that, the blade geometry can be obtained, including blade heights, annulus area, chord and axial chord length, blade pitch, and throat-to-pitch ratio (o/c), as shown in Figure 2 [24,25]. The mean line design model generates a 1D geometry for each stage, including the inlet/outlet angles, the stagger angle, the chord length, the throat opening, and the trailing edge thickness.…”

Section: Meanline Design Modelmentioning

confidence: 99%

“…The number of stages, the number of blades per stage, and the tip clearance values are also provided. According to an analysis conducted by the authors in a previous work, the Aungier loss model [29] is one of the most suitable for sCO 2 axial turbine design [25]. The mean line design tool has been previously verified against multiple cases from the literature.…”

Section: Design Parametermentioning

confidence: 99%

“…In view of the fact that turbine designs were evaluated at a constant rotational speed and loading coefficient of 3000 RPM and 1.0, respectively [25], the number of stages dictates the peripheral blade speed through the desired stage isentropic enthalpy drop. This, in turn, directly defines the hub diameter.…”

Section: Flow Path Designmentioning

confidence: 99%

“…A further reduction in the mass flow rate leads to a poor performance or even negative power output, which indicates that the turbine requires external power to continue running at 3000 RPM. Investigation of the loss breakdown structure of similar turbine stages has revealed that endwall losses are the predominant aerodynamic loss in turbines of this scale operating within sCO2 [25]. However, near the final turbine stages, where the blades are longer, and the boundary layers occupy a narrower portion of the flow path, the overall losses are lower.…”

Section: Off-design Analysismentioning

confidence: 99%

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Design of a 130 MW Axial Turbine Operating with a Supercritical Carbon Dioxide Mixture for the SCARABEUS Project

Abdeldayem,

Salah,

Aqel

et al. 2024

IJTPP

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Supercritical carbon dioxide (sCO2) can be mixed with dopants such as titanium tetrachloride (TiCl4), hexafluoro-benzene (C6F6), and sulphur dioxide (SO2) to raise the critical temperature of the working fluid, allowing it to condense at ambient temperatures in dry solar field locations. The resulting transcritical power cycles have lower compression work and higher thermal efficiency. This paper presents the aerodynamic flow path design of a utility-scale axial turbine operating with an 80–20% molar mix of CO2 and SO2. The preliminary design is obtained using a mean line turbine design method based on the Aungier loss model, which considers both mechanical and rotor dynamic criteria. Furthermore, steady-state 3D computational fluid dynamic (CFD) simulations are set up using the k-ω SST turbulence model, and blade shape optimisation is carried out to improve the preliminary design while maintaining acceptable stress levels. It was found that increasing the number of stages from 4 to 14 increased the total-to-total efficiency by 6.3% due to the higher blade aspect ratio, which reduced the influence of secondary flow losses, as well as the smaller tip diameter, which minimised the tip clearance losses. The final turbine design had a total-to-total efficiency of 92.9%, as predicted by the CFD results, with a maximum stress of less than 260 MPa and a mass flow rate within 1% of the intended cycle’s mass flow rate. Optimum aerodynamic performance was achieved with a 14-stage design where the hub radius and the flow path length are 310 mm and 1800 mm, respectively. Off-design analysis showed that the turbine could operate down to 88% of the design reduced mass flow rate with a total-to-total efficiency of 80%.

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Section: Meanline Design Modelmentioning

confidence: 99%

Section: Meanline Design Modelmentioning

confidence: 99%

Section: Design Parametermentioning

confidence: 99%

Section: Flow Path Designmentioning

confidence: 99%

Section: Off-design Analysismentioning

confidence: 99%

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