Paper 33: Liquid Phase Movement in the Last Stages of Large Condensing Steam Turbines

Valha, J.

doi:10.1243/pime_conf_1969_184_205_02

Cited by 7 publications

(4 citation statements)

References 5 publications

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“…The simulation results of droplet movement and deposition in the ordinary blade were converted into a fitting equation and curve, which depicts a good agreement with the experimental data of Valha [14], shown in previous works [10]. This accordance verified the reliability of DPM in simulating droplet deposition.…”

Section: Ordinary Stationary Bladessupporting

confidence: 85%

Numerical simulation of a new hollow stationary dehumidity blade in last stage of steam turbine

Hou

Xie

et al. 2011

Front. Energy

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As a result of adopting saturation steam and long blade, problems of water erosion of last stage blade for steam turbine become more prominent. In order to improve the operation reliability and efficiency of steam turbine, it is necessary to investigate the nonequilibrium condensing wet steam two phase flow and the dehumidity method. A wet steam model with user defined function based on FLUENT software was investigated to simulate the steam condensing flow in the cascades. The simulation consequences show that the pressure variations in simulation depict a good agreement with the experiment data. On the basis of the discrete phase model simulation results and experiment data, the efficiency of existing dehumidity blade with suction slot was calculated. A new stationary dehumidity blade was designed to elevate the dehumidity efficiency: the efficiency in the suction surface was increased by 21.5%, and that in the pressure surface was increased by 12.2%.

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Section: Ordinary Stationary Bladessupporting

confidence: 85%

Numerical simulation of a new hollow stationary dehumidity blade in last stage of steam turbine

Hou

Xie

et al. 2011

Front. Energy

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“…Figure 5 shows the percentage of deposition of secondary water droplets got by the numerical simulation in this paper and the experimental data by J. Valha [11]. From the figure, it can be seen that the trend of two is the same.…”

Section: Calculation Of Water Droplets Depositionmentioning

confidence: 85%

Numerical Simulation of Water Droplets Deposition on the Last-Stage Stationary Blade of Steam Turbine

Xie¹,

Yu²,

Li³

et al. 2010

EPE

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Based on the method of discrete phase, the law of droplets' deposition in the last stage stationary blade of a supercritical 600 MW Steam Turbine is simulated in the first place of this paper by using the Wet-steam model in commercial software FLUENT, where the influence of inlet angle of water droplets of the stationary blades is also considered. Through the calculation, the relationship between the deposition and the diameter of water droplets is revealed. Then, the amount of droplets deposition in the suction and pressure surface is derived. The result is compared with experimental data and it proves that the numerical simulation result obtained in this paper is reasonable. Finally, a formula of the relationship between the diameter of water droplets and the inlet angle is fit, which could be used for approximate calculation in the engineering applications.

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“…This behaviour is consistent with that described in Young et al 16 , and Valha. 21 It can also be seen from Figure 6 that the deposition rate of the secondary droplets on the downstream blade surface is dependent on the axial distance between two blade rows. A small distance usually leads to a large deposition rate on the downstream blade surface.…”

Section: Calculation Results and Analysismentioning

confidence: 86%

“…Then the maximum diameter of the secondary droplets d max at the trailing edge of a blade can be calculated by equation (10). In actuality, the diameter of the secondary droplets is in the form of a normal distribution, 21 so the mean diameter of the secondary droplets is defined as half of d max , that is d ¼ d max /2. After the average diameter of the secondary droplets is determined, their trajectories can be obtained by solving equation (3).…”

Section: Wetness Losses Calculationmentioning

confidence: 99%

Quantitative evaluation of wetness losses in steam turbines based on three-dimensional simulations of non-equilibrium condensing flows

Liu²,

Xie

et al. 2014

Proceedings of the Institution of Mechanical Engineers, Part A:

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Wet steam flow in steam turbines leads to degraded efficiency and blade erosion in the turbine stages. The Baumann rule, which has been used to predict wetness losses, is increasingly being questioned. More recently, the non-equilibrium condensation model is being increasingly applied to analyse wet steam flow. However, most of the influences caused by wetness losses on the aerodynamics of a wet steam turbine are excluded when this approach is used. Therefore, the efficiency of a wet steam turbine calculated by the non-equilibrium approach does not match the experimentally obtained values. To improve the accuracy of evaluating a wet steam turbine as well as the wetness losses, a quantitative evaluation program of wetness losses has been developed based on the calculation results of wet steam flow with non-equilibrium condensation using the FORTRAN language. Three-dimensional (3D) simulation of the wet steam flow with non-equilibrium condensation in turbine stages is first conducted. Then the 3D results are circumferentially averaged in the meridian plane, which are subsequently used to quantitatively evaluate the wetness losses. The wetness losses are divided into five categories: thermodynamic loss, droplet drag loss, braking loss, capturing loss and centrifuge loss. The wetness losses in the low pressure (LP) cylinder of a fossil steam turbine are calculated. The results show that the thermodynamic loss is mainly generated in the nucleation stage and the last stage of the turbine where non-equilibrium condensation occurs. The droplet drag loss is small in all wet steam stages. The braking loss is the most important component of the wetness losses, except in the nucleation stage. The capturing and centrifuge losses are moderate in the wet steam stages. The total wetness losses in the LP cylinder account for 3.65% of the total output power. This is less than the 5.14% losses predicted by the Baumann rule.

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Paper 33: Liquid Phase Movement in the Last Stages of Large Condensing Steam Turbines

Cited by 7 publications

References 5 publications

Numerical simulation of a new hollow stationary dehumidity blade in last stage of steam turbine

Numerical simulation of a new hollow stationary dehumidity blade in last stage of steam turbine

Numerical Simulation of Water Droplets Deposition on the Last-Stage Stationary Blade of Steam Turbine

Quantitative evaluation of wetness losses in steam turbines based on three-dimensional simulations of non-equilibrium condensing flows

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