Multi-factor optimization study on aerodynamic performance of low-pressure exhaust passage in steam turbines

Cao, Lihua; Si, Hu; Lin, Aqiang; Li, Pan; Li, Yong

doi:10.1016/j.applthermaleng.2017.05.136

Cited by 15 publications

(8 citation statements)

References 13 publications

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“…For an understanding of the detailed flow field characteristics of exhaust passage, the numerical simulation and experimental method are employed. Then, the static pressure recovery and total pressure loss coefficients are used to characterize the performance of exhaust passage [13,14]. Lin et al [15] numerically investigated the three-dimensional flow field of exhaust hood with consideration of various inflow conditions of inlet angle, swirl strength and wetness.…”

Section: Introductionmentioning

confidence: 99%

“…Heat dissipation and turbulent flow will cause a loss [36,37]. The irreversible loss of energy in the flow field can be described by the entropy-increase (∆s), as defined in Equation (13). The presented Equation (13) corresponds to an ideal gas with constant specific heat.…”

mentioning

confidence: 99%

“…221presented Equation(13) corresponds to an ideal gas with constant specific heat. While for wet steam 222 specific heat depends on real steam and water properties parameters.…”

mentioning

confidence: 99%

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Numerical Analysis of Aerodynamic Characteristics of Exhaust Passage with Consideration of Wet Steam Effect in a Supercritical Steam Turbine

Lin

Cai

et al. 2020

Energies

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To investigate the aerodynamic performance of exhaust passage under multi-phase flow, an actual case is conducted in the low-pressure double exhaust passages of 600 MW steam turbine. Then, the flow field is compared and analyzed with and without the built-in extraction pipelines based on the Eulerian–Eulerian homogenous medium multiphase method. Results show that the upstream swirling flow and downstream mixed swirling flow are the main causes to induce the entropy-increase in the exhaust passage. Moreover, the flow loss and static-pressure recovery ability in the exhaust hood are greater than those in the condenser neck. Compared with the flow field without the steam extraction pipelines, the entropy-increase increases, the static pressure recovery coefficient decreases, and the spontaneous condensation rates of wet steam decrease in the downstream area of the pipelines. With the increase of steam turbine loads, an increment in entropy-increase in the exhaust passage is 0.98 J/(kg·K) lower than that without steam extraction pipelines. Moreover, the incrementing range of uniformity coefficient is increased from 14.5% to 40.9% at the condenser neck outlet. It can be concluded that the built-in exhaustion pipeline can improve the aerodynamic performance of exhaust passage and better reflect the real state of the flow field. These research results can serve as a reference for turbine passage design.

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Numerical Analysis of Aerodynamic Characteristics of Exhaust Passage with Consideration of Wet Steam Effect in a Supercritical Steam Turbine

Lin

Cai

et al. 2020

Energies

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“…However, the state of the flow field around the blade is closely related to the blade shape and is complex and nonlinear [25][26][27]. Thus, it is difficult to obtain an accurate cold blade shape directly by using the ideal blade shape as the hot blade shape.…”

Section: Introductionmentioning

confidence: 99%

Hot Blade Shape Reconstruction Considering Variable Stiffness and Unbalanced Load in a Steam Turbine

Zhou

Qiu

et al. 2020

Energies

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The blades in the low-pressure stage of a steam turbine must be reverse engineered according to the ideal blade shape due to the deformation of the blade during operation. A numerical analysis model of the flow field of the blades is proposed, and the model is solved by alternating between the fluid domain and the solid domain. Considering the imbalance of the load acting on the blade surface and the change in the blade stiffness matrix when the steam turbine is running, the Newton–Raphson method is used to calculate the pressure of the steam fluid on the blade surface and the change in the flow field caused by the blade deformation in each time step. The data are exchanged between the fluid domain and the solid domain after a single-step solution is completed. The simultaneous changes in the fluid domain and the solid domain are discretized in very short time steps, and the process of the blade deformation from stationary to running is simulated by accumulating the time steps. Finally, the trends in the change in the blade deformation and the aerodynamic load during the deformation process are analyzed according to the result of the reconstruction of the blade shape.

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“…They found that the wet steam could decrease the flow resistance and improve the flow uniformity in the exhaust passage when the thermodynamic behavior of wet steam was taken into account. Furthermore, Cao et al (2017) found that different swirl strength, wetness, and the inlet air angle of exhaust hood influenced the aerodynamic performance at a great extent. The rotor tip clearance easily affected the steam turbine efficiency (Jang et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Effect of Wet Steam on Aerodynamic Performance of Low-Pressure Exhaust Passage with Last Stage Blade

Lin

Chang

Cao

et al. 2019

JAFM

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The condensation of wet steam has important effects on the behavior of the flow field. To evaluate the aerodynamic performance of exhaust passage influenced by wet steam phase change condensation, a numerical investigation was conducted. Taking a 600 MW steam turbine as an example with consideration of the wet steam from the last stage blade and the steam exhaust of the BFPT (boiler feed water pump turbine), the governing equations of wet steam two-phase flow were adopted by the Eulerian-Eulerian approach. Results show that the wetness in the stator domain increases gradually while the wetness in the rotor domain varies little on the pressure surface and is in small increment on the suction surface. The velocity uniformity can be improved at condenser throat outlet as the mass flow or wetness increases. Moreover, the trend to improve the aerodynamic performance of exhaust passage benefits from the improvement of wetness at the last stage blade inlet. Conversely, with the increment of wetness at the BFPT inlet, the static pressure recovery coefficient reduces by 5.8% and the total pressure loss coefficient increases by 2.4%, resulting in a reduction of aerodynamic performance of exhaust passage.

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Multi-factor optimization study on aerodynamic performance of low-pressure exhaust passage in steam turbines

Cited by 15 publications

References 13 publications

Numerical Analysis of Aerodynamic Characteristics of Exhaust Passage with Consideration of Wet Steam Effect in a Supercritical Steam Turbine

Numerical Analysis of Aerodynamic Characteristics of Exhaust Passage with Consideration of Wet Steam Effect in a Supercritical Steam Turbine

Hot Blade Shape Reconstruction Considering Variable Stiffness and Unbalanced Load in a Steam Turbine

Effect of Wet Steam on Aerodynamic Performance of Low-Pressure Exhaust Passage with Last Stage Blade

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