The flow path characteristics analysis for supercritical carbon dioxide gas turbines

A N Rogalev,V O Kindra,B A Makhmutov,N D Rogalev,E Y Grigoriev,E.V Shamsutdinov,Yu.V Vankov,V.V Sergeev

doi:10.1051/e3sconf/201912401006

Abstract

Rising carbon dioxide concentration in the atmosphere is probably the main reason of global warming. The development of the oxy-fuel combustion cycles is a possible way to decrease the energy sector contribution in the emission process. However, an unusual composition and thermodynamic parameters of the working fluid cause the necessity of revision of the main equipment characteristics, especially for the supercritical carbon dioxide gas turbine. This study presents the method and the results of the flow path preliminary analysis for the new generation gas turbines working on carbon dioxide. The flow path shape with a constant root diameter of seven stages was chosen as the most reasonable due to cheap manufacturing. Influence of reaction degree of stages and velocity ratio on stage geometric parameters are revealed. It was found that the optimal reaction degree and velocity ratio are equal to 0.25 and 0.36 correspondingly. Thermal and constructive stages characteristics of the 350 MW turbine are determined.

Highlights

The results of the preliminary analysis contain turbine stages thermal and structural performance and form a base for the further detailed flow path design
On the other hand, according to the equation (1) the reaction degree increase is followed by reduction of the optimal heat drop and an increase in the number of stages
The algorithm of turbine flow path analysis described above was implemented for the parametric studies of supercritical carbon dioxide gas turbine

Summary

Introduction

The results of the preliminary analysis contain turbine stages thermal and structural performance and form a base for the further detailed flow path design. The flow enriched with carbon dioxide enters the regenerator where it is heated to 700–750°C by turbine exhaust gas. Most of this gas is directed to the combustor as to limit the maximal temperature; a smaller part is supplied to gas turbine cooling. On the contrary to traditional steam and gas turbines, the main Allam cycle flow content is carbon dioxide. The algorithm shows the main factors that determine the turbine stage dimensions It may recommend the flow path shape, a number of stages, reaction degree and the velocity ratio U/cs, where U – circular velocity, cs – specific velocity

Turbo-machine design method

Implementation of the preliminary analysis algorithm

Flow path analysis results for the Allam cycle 350 MW turbine

Findings

Conclusions