Assessment of the heat transfer coefficient for the prediction of ventilation power in steam turbine last stages operating at low load

Mambro, Antonio; Galloni, Enzo; Congiu, Francesco

doi:10.1016/j.tsep.2020.100542

Cited by 5 publications

(2 citation statements)

References 13 publications

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“…Cao et al [8] presented the effects of water droplets on last-turbine stage blades at low steam flow. Mambro et al [9] analyzed heat transfer in the last rotor stage of the steam turbine at minimal steam flow. Using computation modelling, Elmekawy et al [10] examined condensing steam flows in LP steam turbines.…”

Section: Figure 1 Natural-gas-fired Combined Gas-steam Chp Cyclementioning

confidence: 99%

Off-design flow analysis of cogeneration steam turbine with real process data

2022

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This paper presents the concept of reconstruction of the existing coal-fired combined heat and power plant to comply with new European environmental policies. The existing coal-fired boiler will be replaced by two new dual pressure heat recovery steam generators, which will utilize the exhaust gas heat from two new gas turbines. The steam from the heat recovery steam generators will be fed to the existing steam turbine. After the reconstruction, the nominal turbine inlet steam mass-flow of 40 kg/s will be reduced to 30 kg/s. During periods of low heat demand, only one gas turbine and one heat recovery steam generator will be in operation and the live steam mass-flow may drop even to 12 kg/s. Prior to the reconstruction, dedicated tests of the existing steam turbine were carried out using the steam from the existing coal-fired boiler. The goal of the test was to verify the viability of operation with such an extremely low mass-flow. The results of tests show that such operation is possible but inefficient from a power generation point of view. Besides this, the turbine control algorithm needs to be accommodated to this extreme operating regime and additional measures like displacement of the extraction points and steam cooling will be required to control the temperature of the steam extractions. The novelty of this paper is using real pre-reconstruction process data for the assessment of feasibility and efficiency of the post-reconstruction operation of a combined heat and power turbine.

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Section: Figure 1 Natural-gas-fired Combined Gas-steam Chp Cyclementioning

confidence: 99%

Off-design flow analysis of cogeneration steam turbine with real process data

2022

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“…[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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