Details
| Original language | English |
|---|---|
| Title of host publication | ASME Turbo Expo 2013 |
| Subtitle of host publication | Turbine Technical Conference and Exposition, GT 2013 |
| Publication status | Published - 14 Nov 2013 |
| Event | ASME Turbo Expo 2013: Turbine Technical Conference and Exposition, GT 2013 - San Antonio, Tx, United States Duration: 3 Jun 2013 → 7 Jun 2013 |
Publication series
| Name | Proceedings of the ASME Turbo Expo |
|---|---|
| Volume | 6 A |
Abstract
One of the most promising ways to improve the efficiency of modern turbomachinery is the reduction of secondary flowstructures and associated losses. A widely spread approach is the usage of shrouded airfoils in combination with labyrinth-seals. The disadvantage of this arrangement is a small but inevitable labyrinth-leakage flow that tends to increase the secondary-flow structures. The present work investigates how the axial gap of the blade rows and the corresponding shift of the labyrinth's inlet and outlet influences leakage related effects on the flow-field and loss-generation. In order to capture the inter-blade and leakage interaction properly, time-resolved RANS computations of a 11 2 stage low pressure turbine have been performed. Besides accounting for labyrinth seals, fillets have been modeled. The axial gap is varied from 20% to 80% axial chord length. Clockingeffects induced by the axial gap variation are compensated. The leakage flow nearly retains the flow direction of the flow entering the blade row. In case of the largest axial gap, mixing causes the flow-angle of the leakage to tend towards that of the main-flow, thus reducing the incidence on the downstream blade row. Therefore, the turning of the low-momentum flow is increased compared to a small axial gap. This leads to a higher loading in the affected region and an increased passage vortex can be observed. By comparing the entropy generation of computations with and without labyrinth seals, the regions where leakage-related losses occur are identified and the relevant mechanisms are distinguished.
ASJC Scopus subject areas
- Engineering(all)
- General Engineering
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ASME Turbo Expo 2013: Turbine Technical Conference and Exposition, GT 2013. 2013. (Proceedings of the ASME Turbo Expo; Vol. 6 A).
Research output: Chapter in book/report/conference proceeding › Conference contribution › Research › peer review
}
TY - GEN
T1 - Time-Resolved Numerical Study of Axial Gap Effects on Labyrinth-Seal Leakage and Secondary Flow in a LP Turbine
AU - Biester, Marc H.O.
AU - Wiegmann, Florian
AU - Guendogdu, Yavuz
AU - Seume, Joerg R.
PY - 2013/11/14
Y1 - 2013/11/14
N2 - One of the most promising ways to improve the efficiency of modern turbomachinery is the reduction of secondary flowstructures and associated losses. A widely spread approach is the usage of shrouded airfoils in combination with labyrinth-seals. The disadvantage of this arrangement is a small but inevitable labyrinth-leakage flow that tends to increase the secondary-flow structures. The present work investigates how the axial gap of the blade rows and the corresponding shift of the labyrinth's inlet and outlet influences leakage related effects on the flow-field and loss-generation. In order to capture the inter-blade and leakage interaction properly, time-resolved RANS computations of a 11 2 stage low pressure turbine have been performed. Besides accounting for labyrinth seals, fillets have been modeled. The axial gap is varied from 20% to 80% axial chord length. Clockingeffects induced by the axial gap variation are compensated. The leakage flow nearly retains the flow direction of the flow entering the blade row. In case of the largest axial gap, mixing causes the flow-angle of the leakage to tend towards that of the main-flow, thus reducing the incidence on the downstream blade row. Therefore, the turning of the low-momentum flow is increased compared to a small axial gap. This leads to a higher loading in the affected region and an increased passage vortex can be observed. By comparing the entropy generation of computations with and without labyrinth seals, the regions where leakage-related losses occur are identified and the relevant mechanisms are distinguished.
AB - One of the most promising ways to improve the efficiency of modern turbomachinery is the reduction of secondary flowstructures and associated losses. A widely spread approach is the usage of shrouded airfoils in combination with labyrinth-seals. The disadvantage of this arrangement is a small but inevitable labyrinth-leakage flow that tends to increase the secondary-flow structures. The present work investigates how the axial gap of the blade rows and the corresponding shift of the labyrinth's inlet and outlet influences leakage related effects on the flow-field and loss-generation. In order to capture the inter-blade and leakage interaction properly, time-resolved RANS computations of a 11 2 stage low pressure turbine have been performed. Besides accounting for labyrinth seals, fillets have been modeled. The axial gap is varied from 20% to 80% axial chord length. Clockingeffects induced by the axial gap variation are compensated. The leakage flow nearly retains the flow direction of the flow entering the blade row. In case of the largest axial gap, mixing causes the flow-angle of the leakage to tend towards that of the main-flow, thus reducing the incidence on the downstream blade row. Therefore, the turning of the low-momentum flow is increased compared to a small axial gap. This leads to a higher loading in the affected region and an increased passage vortex can be observed. By comparing the entropy generation of computations with and without labyrinth seals, the regions where leakage-related losses occur are identified and the relevant mechanisms are distinguished.
UR - http://www.scopus.com/inward/record.url?scp=84890137346&partnerID=8YFLogxK
U2 - 10.1115/GT2013-95628
DO - 10.1115/GT2013-95628
M3 - Conference contribution
AN - SCOPUS:84890137346
SN - 9780791855225
T3 - Proceedings of the ASME Turbo Expo
BT - ASME Turbo Expo 2013
T2 - ASME Turbo Expo 2013: Turbine Technical Conference and Exposition, GT 2013
Y2 - 3 June 2013 through 7 June 2013
ER -