Investigating the Dehumidification Characteristics of Turbine Stator Cascades with Parallel Channels

Han, Zhonghe; Han, Xu; Xiang, Peng

doi:10.3390/en11092306

Cited by 10 publications

(5 citation statements)

References 31 publications

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“…It can be seen that the numerical results are basically consistent with the experimental results. Simultaneously, non-equilibrium condensation was used as the numerical calculation method, whereby a large number of studies have verified its accuracy [18,24]. Therefore, the mathematical model used is accurate in this paper, and the simulation results are also credible.…”

Section: Mathematical Model Verificationmentioning

confidence: 82%

Distribution Characteristics of High Wetness Loss Area in the Last Two Stages of Steam Turbine under Varying Conditions

et al. 2022

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Wetness loss of a steam turbine seriously affects the security of the unit when operating in deep peak regulation. To obtain the distribution characteristics of the high wetness loss area under different working conditions, especially low-load conditions, the last two stages of the low-pressure cylinder (LPC) of a 600 MW steam turbine were simulated using the non-equilibrium condensation model proposed in this study. The nucleation rate distribution, supercooling degree, and steam velocity droplet were analyzed. Consequently, the diameter distribution of coarse water droplets under 100%, 50%, 40%, 30%, and 20% THA conditions and the distribution of the thermodynamic loss and water droplet resistance loss were obtained. Thermodynamic loss mainly occurred at the front end of second-stage stator blades and trailing end of the last-stage stator blades. The water droplet resistance loss mainly occurred at 40% of the blade height and at the tip of the last-stage stator blades. Moreover, with a reduction in the unit load, the thermodynamic loss continued to decrease, but the water droplet resistance loss continued to increase.

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Section: Mathematical Model Verificationmentioning

confidence: 82%

Distribution Characteristics of High Wetness Loss Area in the Last Two Stages of Steam Turbine under Varying Conditions

et al. 2022

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“…The temperature at the last stage does not drop to the value of the saturation pressure of steam at a given pressure. However, this phenomena occurs in conventional steam turbines [66][67][68]. The key thermodynamic phenomena occurring in the flow of a gas-steam turbine concern the behavior of the mixture of fluids as the pressure drops during the transfer of mechanical energy to the turbine stages.…”

Section: Comparison Of Temperaturementioning

confidence: 99%

Example of Using Particle Swarm Optimization Algorithm with Nelder–Mead Method for Flow Improvement in Axial Last Stage of Gas–Steam Turbine

Ziółkowski,

Witanowski,

Głuch

et al. 2024

Energies

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This article focuses principally on the comparison baseline and the optimized flow efficiency of the final stage of an axial turbine operating on a gas–steam mixture by applying a hybrid Nelder–Mead and the particle swarm optimization method. Optimization algorithms are combined with CFD calculations to determine the flowpaths and thermodynamic parameters. The working fluid in this study is a mixture of steam and gas produced in a wet combustion chamber, therefore the new turbine type is currently undergoing theoretical research. The purpose of this work is to redesign and examine the last stage of the gas–steam turbine’s flow characteristics. Among the optimized variables, there are parameters characterizing the shape of the endwall contours within the rotor domain. The values of the maximized objective function, which is the isentropic efficiency of the turbine stage, are found from the 3D RANS computation of the flowpath geometry changing during the improvement scheme. The optimization process allows the stage efficiency to be increased by almost 4 percentage points. To achieve high-quality results, a mesh of over 20 million elements is used, where the percentage error in efficiency between the previous and current mesh sizes drops below 0.05%.

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“…The existing dehumidification technology of steam turbine includes blade surface heating, steam purging, groove diversion, dehumidification gap, etc. (Han et al, 2018;. The method is to introduce high temperature steam into the cascade cavity.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of the wet steam condensation flow characteristics in stator cascade with blade surface heating

Han

Yuan

Zhao

et al. 2020

Engineering Applications of Computational Fluid Mechanics

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The scientific and effective control of steam wetness in steam turbines is of great significance for improving power generation efficiency. Based on the research status of wet steam, the influence of different surface heating intensity in a stator cascade was studied. The distribution of condensation flow parameters in White cascade under 0-700 kW/m 2 surface heating intensity is calculated. On this basis, the positive heating intensity region was determined and refined to obtain the best heating condition with higher accuracy. The results show that the condensation is restrained and the outlet wetness is decreased as the blade surface heating intensity increases. The steam wetness and droplet diameter in the flow field can be controlled by adding heating intensity. Additionally, at the initial stage of applying heat to the blade, an increasing enthalpy drop occurs, and the entropy increase experiences a decline, while negative effects rapidly emerge if the heating intensity is too high. The optimum heating intensity is 120 kW/m 2. Compared with the 0 kW/m 2 , the average outlet wetness, total pressure loss coefficient and entropy increase of 120 kW/m 2 surface heating intensity can be reduced by 1.1266%, 15.5% and 1.7%, respectively, and the enthalpy drop can be increased by 1.7%.

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Investigating the Dehumidification Characteristics of Turbine Stator Cascades with Parallel Channels

Cited by 10 publications

References 31 publications

Distribution Characteristics of High Wetness Loss Area in the Last Two Stages of Steam Turbine under Varying Conditions

Distribution Characteristics of High Wetness Loss Area in the Last Two Stages of Steam Turbine under Varying Conditions

Example of Using Particle Swarm Optimization Algorithm with Nelder–Mead Method for Flow Improvement in Axial Last Stage of Gas–Steam Turbine

Numerical investigation of the wet steam condensation flow characteristics in stator cascade with blade surface heating

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