Study of a Supercritical CO2 Turbine With TIT of 1350 K for Brayton Cycle With 100 MW Class Output: Aerodynamic Analysis of Stage 1 Vane

Abstract

This study seeks to design the aerodynamic features a first stage vane for a 100 MW class supercritical CO2 Brayton cycle turbomachine. For a turbine inlet temperature of 1350 K, the recuperated configuration is found to provide the highest cycle efficiency, and the corresponding cycle parameters are then used to design the turbine stages. A 6-stage turbine is selected and the first stage is designed following a one-dimensional mean line approach. Initial mean line turbomachine parameters (work coefficient and flow coefficient) are selected to provide high thermodynamic efficiency and simple radial equilibrium equation principles. Turning loss correlations are utilized to define and optimize hub and casing velocity triangle parameters. Typical turbomachinery characteristic parameters are used to compare the carbon dioxide turbine with typical air combustion turbines. Detailed aerodynamic analysis is performed on a complete three-dimensional model of the vane flow field using a commercial computational fluid dynamics code, STAR-CCM+. Actual properties of the working fluid are input to the model from the REFPROP database provided by the US National Institute of Standards and Technology (NIST). The detailed flow field is computed, from which aerodynamic loss coefficients are calculated. The computer model confirms that the design is successful in turning supercritical carbon dioxide at the prescribed angle and pressure. However, results of the real fluid simulation show that aerodynamic losses caused the stage efficiency to be about 4% below the design target.

Numerical Study of Leakage and Rotordynamic Performance of Staggered Labyrinth Seals Working with Supercritical Carbon Dioxide

“…. ., 14) is the calculated leakage flow rate under operating conditions and M 0 is the leakage flow rate of the original model. Table 4 gives a comparison of the labyrinth seal leakage flow rate under various calculation conditions.…”

“…In recent years, many research institutions (Sandia National Laboratories [5], Bechtel Marine Propulsion Corporation and Bettis Atomic Power Laboratory [6,7], Southwest Research Institute and General Electric [8][9][10], Tokyo Institute of Technology [11], Korea Advanced Institute of Science and Technology [12,13], University of Central Florida [14], etc.) have carried out experimental investigations or field tests to study the performance of turbomachines including turbine expander and turbine compressor with S-CO 2 .…”

Supercritical Carbon Dioxide Turbine Design and Arrangement Optimization

“…In addition, Kim et al conducted aerodynamic analysis on the sCO 2 turbine designed by the Korea Advanced Institute of Science and Technology and optimized the blades to improve the aerodynamic efficiency of the turbine (Kim et al, 2006;Kim et al, 2008). Schmitt et al designed a 6-stage sCO 2 turbine with a power of 100 MW and an inlet temperature of 1,077 °C (Schmitt et al, 2014). In this study, the parameters of the speed triangle were optimized, and the total power and efficiency of the turbine met the design requirements.…”

A Code for the Preliminary Design of Cooled Supercritical CO2 Turbines and Application to the Allam Cycle

“…Most of the works available in the literature focus on uncooled sCO 2 machine and are mainly derived from the study of nuclear or external combustion applications, where the maximum temperatures are limited by the operation of the reactor or by the heat transfer process. For instance, Han et al [19] study the turbine of a 5 MW el reheated sCO 2 Bryton cycle test loop with a maximum cycle temperature of 873.15 K; Moroz et al [15] and Zhang et al [16] perform the design of turbines for nuclear power applications operating at inlet temperatures around 750 K. Even in the studies considering hightemperature machines, as in the work of Schmitt et al [20], the analysis focuses only on the fluid-dynamic losses and do not deal with the blade cooling requirements in detail.…”