Experimental study and modelling of the ventilation power and maximum temperature of low-pressure steam turbine last stages at low load

Mambro, Antonio; Congiu, Francesco; Galloni, Enzo; Canale, Laura

doi:10.1016/j.apenergy.2019.03.003

Cited by 11 publications

(2 citation statements)

References 12 publications

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“…Further research by Sigg and Rice 12 showed that the system RI was influenced by the exhaust shape. Nonsynchronous unsteady aerodynamic excitations in the last stage were also found by Liu et al 13 and Tanuma et al 14 Besides the flow fluctuation, Beevers et al 15 and Mambro et al 16,17 found that in this region, due to lack of axial flow, heat was difficult to dissipate through convection, and the temperature of the flow increased abnormally, which caused the LSMB tip and the casing to be in high temperature.…”

Section: Introductionmentioning

confidence: 60%

Numerical investigation on flow instabilities in low-pressure steam turbine last stage under different low-load conditions

Lin²,

Yang³

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part A:

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The modern power generation system requires steam turbines operating at flexible operating points, and flow instabilities readily occur in the low-pressure (LP) last stage under low-load conditions, which may cause failure of the last stage moving blades. Some studies have shown that within this operating range, a shift of the operating point may lead to flow instabilities. Numerical simulation has gradually developed into a popular method for such researches, but it is expensive for a complex model, which has to be balanced between efficiency and accuracy. This work is divided into three parts: Firstly, one of the low-load conditions is selected to provide both URANS model and the Scale-Adaptive Simulation (SAS) model. The results of the two models are compared to evaluate specific flow phenomena; Secondly, through calculations of different low-load conditions, the flow structure and propagation characteristics of instabilities in the last stage are obtained; Finally, flow analysis is applied to explain the formation mechanism of flow instabilities in LP steam turbines. The results show that, the introduction of SAS model increases the randomness of flow over time, but does not fundamentally change the flow instabilities. Flow instabilities take different forms at different flow rate, from rotating instability to rotating stall. The formation of flow instabilities is related to the radial flow in the cascade passages.

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Section: Introductionmentioning

confidence: 60%

Numerical investigation on flow instabilities in low-pressure steam turbine last stage under different low-load conditions

Lin²,

Yang³

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part A:

View full text Add to dashboard Cite

show abstract

“…[1][2][3]. For turbine designers it is important to define well the output, and for low volume conditions even the input of last stages [4][5][6] using numerical or sometimes even experimental methods. In recent articles [7,8] aerodynamic instability of the flow has been discussed in the turbine last stages.…”

Section: Introductionmentioning

confidence: 99%

Flow and Vibration in the Small Steam Turbine Last Stage

2022

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The paper deals with evaluation of experimental data obtained from the real-size 30 MW output Waste to Energy steam turbine. For many turbine regimes pressures in the last stage area were obtained. At the same time amplitudes of blade tips vibrations were measured of last rotor blades using the blade tip timing system and axial velocity of the steam at the last stage outlet. The obtained data are mutually correlated and relations are analysed between increased vibration values and pressure ratios at the last stage. Increased tip vibrations occur mainly in the area when the pressure ratio over the last blade tip and root is higher than one. In this case there is no expansion, but compression in the last stage of the turbine. The presented results contribute to understanding of processes in the last stage of the steam turbine, mainly for those regimes of turbine operation when its output is lower than 20 % of the nominal output, e.g. during the island regime.

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Modelling of low-pressure steam turbines operating at very low flowrates: A multiblock approach

Mambro¹,

Galloni

Congiu³

et al. 2019

Applied Thermal Engineering

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Experimental study and modelling of the ventilation power and maximum temperature of low-pressure steam turbine last stages at low load

Cited by 11 publications

References 12 publications

Numerical investigation on flow instabilities in low-pressure steam turbine last stage under different low-load conditions

Numerical investigation on flow instabilities in low-pressure steam turbine last stage under different low-load conditions

Flow and Vibration in the Small Steam Turbine Last Stage

Modelling of low-pressure steam turbines operating at very low flowrates: A multiblock approach

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