Numerical Study of Partial Admission Stages in Steam Turbine (Efficiency Improvement by Optimizing Admission Arc Position)

Abstract

This paper deals with an application of computational fluid dynamics (CFD) to partial admission stages in a steam turbine. The calculation of partial admission stages requires unsteady analysis and full circle modeling. Therefore, quasi-3-dimensional (Q-3D) analysis of the mean radius is conducted to reduce computational load. First, an experiment using the air turbine is carried out. The result is in good agreement with the result of CFD analysis under the same conditions as the experiment, and the application of the Q-3D method to partial admission stage analysis is validated. Using this method, 2-stage analysis of partial admission is conducted. The influence of the circumferential position of the admitted arc on stage efficiency is discussed. The efficiency difference is related to the windage loss caused by pressure distribution in the circumferential direction. It is found that there is an optimum circumferential position of the admitted arc from the point of view of turbine efficiency.

Research on the Aerodynamic Performance and Collaborative Optimization Design of the Full-Scale Compact Inlet Chamber of a Nuclear-Powered Steam Turbine

“…(1) Non-uniform intake imposes bending and radial moments on the rotor, which may result in rotor vibrations [6][7][8] and even faults [9], thus affecting bearing safety [10]; (2) Non-uniform intake causes mixed loss in the cascade channel [11][12][13][14] or blast loss [15,16], and a mismatch between the chamber outlet airflow angle and the geometric angle of the first stage static cascade causes shock loss [17]; (3) Non-uniform intake causes an increase in the amplitude of airflow excitation forces on the first-stage dynamic and static lobes [18] and complex excitation force frequencies [5,13,[19][20][21][22].…”

“…(1) Non-uniform intake imposes bending and radial moments on the rotor, which may result in rotor vibrations [6][7][8] and even faults [9], thus affecting bearing safety [10]; (2) Non-uniform intake causes mixed loss in the cascade channel [11][12][13][14] or blast loss [15,16],…”

Archives of Thermodynamics

“…Calculations were performed using CFD methods. In [7] a CFD analysis of quasi three dimensional model with no change of pressure distribution in the radial direction was used to analyze partially admitted air turbine. The calculations were supported by experimental results.…”

Turbine Load Oscillation Fault Caused by Its HP-Valve Problem

“…In addition the sliding pressure operation that recognized as one of the most effective method to improve turbines part load economy [6][7][8][9]. However, the designation of sequence valve inappropriate rule that affect the safe and stable operation of the unit is a very complex job [9][10][11][12]. And load oscillation is one of serious problem that can affect the ability of unit frequency regulation and peak regulation even can caused grid load oscillation.…”