Computational fluid dynamics (CFD) methods are applied to the analysis of a low-pressure turbine exhaust hood at a typical steam power generating station. A Navier-Stokes solver, capable of modeling all the viscous terms, in a Reynolds-averaged formulation, was used. The work had two major goals. The first was to develop a comprehensive understanding of the complex three-dimensional flow fields that exist in the exhaust hood at representative operating conditions. The second was to evaluate the relative benefits of a flow guide modification to optimize performance at a selected operating condition. Also, the influence of simulated turbine discharge characteristics, relative to uniform hood entrance conditions, was evaluated. The calculations show several interesting and possibly unique results. They support use of an integrated approach to the design of turbine exhaust stage blading and hood geometry for optimum efficiency.

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The results of an experimental study to evaluate the performance and low-flow stability limits of several isolated inlet models are presented. The lowest drag approach to provide large-flow regulation was a bypass device for handling the excess airflow. The use of compression surface modulation or a boundary-layer bleed system to dispose of the excess airflow incurred similar drag penalties which were significantly greater than those for the bypass configuration. A good correlation of low-flow stability range data with a shock-lip geometry parameter is demonstrated. A by-product of this work is the introduction of a drag parameter that allows a more complete approach to quantifying inlet drag characteristics. Nomenclaturebetween lip and normal shock position for slipstream ingestion P = pressure W c = corrected weight flow a, 13 = lip angles 6 = compression surface turning angle 0 = angle between lip and leading edge of the shockgenerating surface 6 = discharge angle Subscripts 0 = freestream 2 = engine face B = bleed exit c = capture e = bypass exit T = total and throat