It has been widely recognized for some decades that it is essential to accurately represent the strong coupling between the last stage blades (LSB) and the diffuser inlet, in order to correctly capture the flow through the exhaust hoods of steam turbine low pressure cylinders. This applies to any form of simulation of the flow, i.e., numerical or experimental. The exhaust hood flow structure is highly three-dimensional and appropriate coupling will enable the important influence of this asymmetry to be transferred to the rotor. This, however, presents challenges as the calculation size grows rapidly when the full annulus is calculated. The size of the simulation means researchers are constantly searching for methods to reduce the computational effort without compromising solution accuracy. However, this can result in excessive computational demands in numerical simulations. Unsteady full-annulus CFD calculation will remain infeasible for routine design calculations for the foreseeable future. More computationally efficient methods for coupling the unsteady rotor flow to the hood flow are required that bring computational expense within realizable limits while still maintaining sufficient accuracy for meaningful design calculations. Research activity in this area is focused on developing new methods and techniques to improve accuracy and reduce computational expense. A novel approach for coupling the turbine last stage to the exhaust hood employing the nonlinear harmonic (NLH) method is presented in this paper. The generic, IP free, exhaust hood and last stage blade geometries from Burton et al. (2012. “A Generic Low Pressure Exhaust Diffuser for Steam Turbine Research,”Proceedings of the ASME Turbo Expo, Copenhagen, Denmark, Paper No. GT2012-68485) that are representative of modern designs, are used to demonstrate the effectiveness of the method. This is achieved by comparing results obtained with the NLH to those obtained with a more conventional mixing-plane approach. The results show that the circumferential asymmetry can be successfully transferred in both directions between the exhaust hood flow and that through the LSB, by using the NLH. This paper also suggests that for exhaust hoods of generous axial length, little change in Cp is observed when the circumferential asymmetry is captured. However, the predicted flow structure is significantly different, which will influence the design and placement of the exhaust hood internal “furniture.”
Skip Nav Destination
Article navigation
April 2014
Research-Article
The Influence of Inlet Asymmetry on Steam Turbine Exhaust Hood Flows
Zoe Burton,
Zoe Burton
1
e-mail: zoe.burton@durham.ac.uk
1Corresponding author.
Search for other works by this author on:
Grant L. Ingram
Grant L. Ingram
e-mail: g.l.ingram@durham.ac.uk
School of Engineering and Computing Sciences,
School of Engineering and Computing Sciences,
Durham University
,South Road
,Durham DH1 3LE
, UK
Search for other works by this author on:
Zoe Burton
e-mail: zoe.burton@durham.ac.uk
Simon Hogg
e-mail: simon.hogg@durham.ac.uk
Grant L. Ingram
e-mail: g.l.ingram@durham.ac.uk
School of Engineering and Computing Sciences,
School of Engineering and Computing Sciences,
Durham University
,South Road
,Durham DH1 3LE
, UK
1Corresponding author.
Contributed by the Turbomachinery Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received November 4, 2013; final manuscript received November 8, 2013; published online December 19, 2013. Editor: David Wisler.
J. Eng. Gas Turbines Power. Apr 2014, 136(4): 042602 (9 pages)
Published Online: December 19, 2013
Article history
Received:
November 4, 2013
Revision Received:
November 8, 2013
Citation
Burton, Z., Hogg, S., and Ingram, G. L. (December 19, 2013). "The Influence of Inlet Asymmetry on Steam Turbine Exhaust Hood Flows." ASME. J. Eng. Gas Turbines Power. April 2014; 136(4): 042602. https://doi.org/10.1115/1.4026003
Download citation file:
Get Email Alerts
Experimental Identification Of Blade Tip Rub Forces At Engine Relevant Temperatures And Speeds
J. Eng. Gas Turbines Power
Study Of Tandem Rotor Dual Wake Interaction With Downstream Stator Under Unsteady Numerical Approach
J. Eng. Gas Turbines Power
Experimental Design Validation of a Swirl-Stabilized Burner With Fluidically Variable Swirl Number
J. Eng. Gas Turbines Power (April 2025)
Experimental Characterization of a Bladeless Air Compressor
J. Eng. Gas Turbines Power (April 2025)
Related Articles
Efficient Methods for Predicting Low Pressure Steam Turbine Exhaust Hood and Diffuser Flows at Design and Off-Design Conditions
J. Eng. Gas Turbines Power (August,2015)
Unsteady Interactions Between Axial Turbine and Nonaxisymmetric Exhaust Hood Under Different Operational Conditions
J. Turbomach (July,2012)
Enhanced External Aerodynamic Performance of a Generic Combustor Using An Integrated OGV/Prediffuser Design Technique
J. Eng. Gas Turbines Power (January,2007)
Backward Traveling Rotating Stall Waves in Centrifugal Compressors
J. Turbomach (January,2004)
Related Proceedings Papers
Related Chapters
Other Components and Variations
Axial-Flow Compressors
Control and Operational Performance
Closed-Cycle Gas Turbines: Operating Experience and Future Potential
Aerodynamic Design and Performance Analysis of Exhaust Diffusers
Turbine Aerodynamics: Axial-Flow and Radial-Flow Turbine Design and Analysis