Effects of inlet swirl on the flow in a steam turbine exhaust hood

Šťastný, M.; Tajč, Ladislav; Kolár, Petr; Tucek, Antonín

doi:10.1007/s11630-000-0072-4

Cited by 10 publications

(7 citation statements)

References 3 publications

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“…The counter-rotating outlet vortices in the condenser neck have a detrimental effect on condenser efficiency, as it is desirable to have a uniform distribution of steam across the heat transfer surface. Reverse flow at the core of each vortex has been noted by multiple researchers including Stastny in 2000 [20]. The low energy at the core drives the main flow outwards to the walls of the condenser neck, resulting in higher velocities in this region and the bulk of the flow discharging down the endwalls in a highly nonuniform flow, Fig.…”

Section: Additional Vorticesmentioning

confidence: 86%

“…13 [1,20]. This can sometimes by up to 7% [13], with the discrepancy increasing with increasing vortex size.…”

Section: Numerical and Experimental Methodologiesmentioning

confidence: 97%

“…Typical values of Cp are around 0.2-0.4 [3,10,13,15,19,39]. Discrepancies between experimental and numerical results are primarily attributed to unrepresentative boundary conditions [20], inaccuracies in turbulence and transitional modeling [40] and simplification of geometries [1].…”

Section: Numerical and Experimental Methodologiesmentioning

confidence: 99%

“…Although widely acknowledged that each structural reinforcement contributes significantly to the loss in the hood due to flow blockage, almost all choose to examine the flow structure in an "empty" casing, free of all internal geometry, due to the increased computational power requirement. Neglecting the reinforcements contributes to discrepancies between field data and experimental [20].…”

Section: 4mentioning

confidence: 98%

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A Literature Review of Low Pressure Steam Turbine Exhaust Hood and Diffuser Studies

Burton¹,

Ingram²,

Hogg

2013

Journal of Engineering for Gas Turbines and Power

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This paper summarizes the findings from research studies carried out over the last 30 years, to better understand the flows in steam turbine low pressure exhaust hoods and diffusers. The work aims to highlight the areas where further study is still required. A detailed description of the flow structure is outlined and the influence of the last turbine stage and the hood geometry on loss coefficient is explored. At present, the key challenge faced is numerically modeling the three-dimensional, unsteady, transonic, wet steam exhaust hood flow given the impractically high computational power requirement. Multiple calculation simplifications to reduce the computational demand have been successfully verified with experimental data, but at present there is no 'best-practice' approach to reduce the computational time for routine design exercises. This paper highlights the importance of coupling the exhaust hood to the last stage steam turbine blades to capture the interaction; ensuring the total pressure and swirl angle profiles, along with the tip leakage jet are accurately applied to the diffuser inlet. The nonaxial symmetry of the exhaust hood means it is also important to model the full blade annulus. More studies have emerged modeling the wet steam and unsteady flow effects, but more work is required in this area to fully understand the impact on the flow structure.

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Section: Additional Vorticesmentioning

confidence: 86%

“…13 [1,20]. This can sometimes by up to 7% [13], with the discrepancy increasing with increasing vortex size.…”

Section: Numerical and Experimental Methodologiesmentioning

confidence: 97%

Section: Numerical and Experimental Methodologiesmentioning

confidence: 99%

Section: 4mentioning

confidence: 98%

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A Literature Review of Low Pressure Steam Turbine Exhaust Hood and Diffuser Studies

Burton¹,

Ingram²,

Hogg

2013

Journal of Engineering for Gas Turbines and Power

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“…They found that the performance is a strong function of inflow conditions. Moreover, the numerical analysis in the exhaust hood can be concluded that the major influences of flow loss result from the rotational flow downstream of last stage blades (LSBs) leading to a non-uniform distribution of flow field, tip leakage jet, asymmetry vortices formed within the diffuser, and flow separation along with the flow guide [16][17][18]. These phenomena can be corroborated by comparison with the experimental investigations [19][20][21].…”

Section: Introductionmentioning

confidence: 82%

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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Investigations on the improving aerodynamic performances of last stage steam turbine and exhaust hood under design and off design conditions

Liu

2015

J. Therm. Sci.

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Effects of inlet swirl on the flow in a steam turbine exhaust hood

Cited by 10 publications

References 3 publications

A Literature Review of Low Pressure Steam Turbine Exhaust Hood and Diffuser Studies

A Literature Review of Low Pressure Steam Turbine Exhaust Hood and Diffuser Studies

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

Investigations on the improving aerodynamic performances of last stage steam turbine and exhaust hood under design and off design conditions

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