Retrofittable Solutions Capability for Gas Turbine Compressors

Ricci, M; Mosele, Stefano Gino; Benvenuto, Marcello; Astrua, Pio; Pacciani, Roberto; Marconcini, Michele

doi:10.3390/ijtpp7010003

Cited by 4 publications

(3 citation statements)

References 19 publications

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“…12). Studies of the same engine by Ricci et al (2021Ricci et al ( , 2022 with a different CFD solver and by Mosele et al (2019) and Hedkvist (2019) with a through-flow solver, show similar trends regarding the change in loading due to a higher blow-off rate.…”

Section: Bleed Extraction Studymentioning

confidence: 77%

Simulation of a Multistage Compressor at Low Load Operation with Additional Bleed Air Extraction for Minimum Environmental Load Reduction

Goinis¹,

Benvenuto²,

Mosele³

et al. 2022

Proceedings of Global Power &Amp; Propulsion Society

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The need for more flexible operation of gas-fired power plants has led manufacturers to exploit possibilities to retrofit existing systems and increase turndown capabilities, lowering the minimum environmental load (MEL) - the lowest output at which the unit can operate and still meet environmental emissions limits. A possible measure for the compressor to enable a reduced MEL is to extract significant mass flow rates through the bleed ports in operation with a closed IGV to lower the mass flow entering the combustor, enabling a further load reduction while maintaining emissions. For this measure to be implemented, a stable operation of the compressor has to be ensured at the reduced MEL conditions. It is well known that bleed-air offtake at full speed shifts the loading towards the rear stages of the compressor. At MEL, the rear stages already operate at an increased loading compared to base-load. Therefore, to confirm the viability of bleed offtake as a turndown strategy, the effects on performance and stability have to be quantified for operation at MEL. Of particular interest is how an increase in air extraction through the bleed ports influences the stability of the compressor at MEL, especially when the offtake is from low pressure. Information on the degradation of the stability margin due to the additional bleed-air extraction at MEL is gained through numerical simulations. Full-compressor CFD simulations of an F-class gas turbine at reduced MEL conditions are performed. The influence of several geometrical and numerical modeling details is studied, and the model is validated against a comprehensive set of experimental data. The numerical results show good agreement with the experimental data, even with increased bleed air extraction. It can be concluded that bleed-air extraction is a capable method of reducing the compressor discharge mass flow rate significantly. The extraction rate is limited by the stability of the last compressor stages. To verify the integrity of the whole GT at operation under such conditions, e.g., the thermal state of hot parts, further analysis should be performed.

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Section: Bleed Extraction Studymentioning

confidence: 77%

Simulation of a Multistage Compressor at Low Load Operation with Additional Bleed Air Extraction for Minimum Environmental Load Reduction

Goinis¹,

Benvenuto²,

Mosele³

et al. 2022

Proceedings of Global Power &Amp; Propulsion Society

View full text Add to dashboard Cite

show abstract

“…Because axial compressors often operate under off-design conditions, aircraft engines must have good performance [1]. The performance of the compressor under off-design conditions must be accurately estimated during the engine design stage [2,3].…”

Section: Introductionmentioning

confidence: 99%

Improved Body Force Model for Estimating Off-Design Axial Compressor Performance

Huang

Xia³

et al. 2022

Energies

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Based on the COMSOL software, body forces substituted into the Reynolds-averaged Navier–Stokes (RANS) equations as the source terms instead of the actual blade rows were improved to better predict the compressor performance. Improvements in parallel body force modeling were implemented, central to which were the local flow quantities. This ensured accurate and reliable off-design performance prediction. The parallel force magnitude mainly depended on the meridional entropy gradient extracted from three-dimensional (3D) steady single-passage RANS solutions. The COMSOL software could easily and accurately translate the pitchwise-averaged entropy into the grid points of the body force domain. A NASA Rotor 37 was used to quantify the improved body force model to represent the compressor. Compared with the previous model, the improved body force model was more efficient for the numerical calculations, and it agreed well with the experimental data and computational fluid dynamics (CFD) results. The results indicate that the improved body force model could quickly and efficiently capture the flow field through a turbomachinery blade row.

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“…The first solution consists of the variation of the IGV stagger angle (a practice that is generally used to change load condition), to decrease the inlet compressor mass flow below the standard MEL value. The second solution opens one or more blow-off valves at the core of the compressor in order to bypass part of the compressed air directly in the exhaust diffuser and save the fuel needed to heat it [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Predicting the Impact of Compressor Flexibility Improvements on Heavy-Duty Gas Turbines for Minimum and Base Load Conditions

Ricci

Benvenuto²,

Mosele³

et al. 2022

Energies

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The increasing importance of renewable energy capacity in the power generation scenario, together with the fluctuating consumer energy demand, forces conventional fossil fuel power generation systems to promptly respond to relevant and rapid load variations and to operate under off-design conditions during a major fraction of their lives. In order to improve existing power plants’ flexibility in facing energy surplus or deficit, retrofittable solutions for gas turbine compressors are proposed. In this paper, two different operation strategies, variable inlet guide vanes (IGVs) and blow-off extraction (BO), are considered for enabling partial load and minimum environmental load operation, and thus to identify implementation opportunities in existing thermal power plants. A typical 15-stage F-class gas turbine compressor is chosen as a test case and some energy demand scenarios are selected to validate the adopted solutions. The results of an extensive 3D, steady, CFD analysis are compared with the measurements coming from an experimental campaign carried out in the framework of the European Turbo-Reflex project. It will be shown how the combined strategies can reduce gas turbine mass flow rate and power plant output, without significantly penalizing efficiency, and how such off-design performance figures can be reliably predicted by employing state-of-the-art CFD models.

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Retrofittable Solutions Capability for Gas Turbine Compressors

Cited by 4 publications

References 19 publications

Simulation of a Multistage Compressor at Low Load Operation with Additional Bleed Air Extraction for Minimum Environmental Load Reduction

Simulation of a Multistage Compressor at Low Load Operation with Additional Bleed Air Extraction for Minimum Environmental Load Reduction

Improved Body Force Model for Estimating Off-Design Axial Compressor Performance

Predicting the Impact of Compressor Flexibility Improvements on Heavy-Duty Gas Turbines for Minimum and Base Load Conditions

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