Investigation of Energy Loss on Fractional Deposition in Last Stages of Condensing Steam Turbine Due to Blade Shape and Moisture Droplet Size

Abstract

The steam consumption in a turbine within an operating pressure range determines the effectiveness of thermal energy conversion to electric power generation in a turbo-alternator. The low pressure (LP) stage of the steam turbine produces largest amount of steam to shaft-power in comparison to other stages of turbine although susceptible to various additional losses due to condensation of wet steam near penultimate and ultimate stages. The surface deposition in blade is caused by inertial impaction and turbulent-diffusion. With increasing blade stagger angle along the larger diameter of blading, the fractional deposition of wet steam is largely influenced by blade shape. From this background, the aim of this work is to predict the effect of mathematical models through computational fluid dynamics analysis on the characterization of thermodynamic and mechanical loss components based on unsaturated vapor water droplet size and pressure zones in LP stages of steam turbine and to investigate the influence of droplet size and rotor blade profile on cumulative energy losses due to condensation and provide an indication about the possible conceptual optimization of blade profile design to minimize moisture-induced energy losses.

A blackbox optimization of volumetric heating rate for reducing the wetness of the steam flow through turbine blades

“…It facilitates the solution of equations. It is confirmed by other researches that this approach provides acceptable results in wet steam flow simulations (see, e.g., [43]).…”

Research on Water Droplet Movement Characteristics in the Last Two Stages of Low-Pressure Cylinder of Steam Turbine Under Low Load Conditions

“…Through experiments, it has been obtained that the diameter of a water droplet is between 0 and 1 μm (Petr and Kolovratnik, 2000;Tatsuno and Nagao, 1986;White and Hounslow, 2000). In the process of movement, a drop of water is deposited on the surface of the steam turbine blade in two ways, inertia and turbulent diffusion due to the action of force (Sengupta and Bhattacharya, 2017;Sengupta, 2016;Sengupta and Bhattacharya, 2018). Schuster S (Schuster et al, 2016), Rossi P (Rossi et al, 2018) and Starzmann J (Starzmann et al, 2014) and others respectively combined theoretical calculations and numerical simulations to analyze the characteristics of the primary water droplets under rated conditions.…”