A Generic Low Pressure Exhaust Diffuser for Steam Turbine Research

Abstract

Durham University have embarked on a new research initiative in low pressure (LP) steam turbine exhaust hoods. An extensive literature review has highlighted the importance of applying representative conditions at inlet to the exhaust diffuser, specifically accurate total pressure and swirl angle distributions, in numerical simulations to generate flow fields within the hood in line with field data. With commercial sensitivity surrounding industrial designs for exhaust hoods and last stage blades, Durham University have developed a generic, research-level exhaust diffuser geometry and accompanying last stage blade to encourage the expansion of academic research in the field. Preliminary CFD calculations on the LP exhaust has shown the design produces a representative flow structure, capturing the primary sources of loss; the separation along the bearing cone and at the tip of the flow guide.