Session: Student Poster Competition

Submission Number: 185533

Case Study on Small-Scale Supercritical Co2 Axial-Flow Turbine 

The small-scale CO₂ cycle offers a more efficient and compact option for distributed energy systems. Within this system, the small-scale CO2 turbine, as the core component for thermal-to-power conversion, requires particular attention. Currently, CO2 turbines with an output power <500 kW predominantly adopt radial single-stage impeller designed under high rotational speed to achieve high output performance. However, due to challenges such as rotor stability, significant axial thrust, and cooling difficulties, it is hard to achieve the expected targets. In contrast, axial turbines can achieve efficient expansion through multi-stage design, and the axial thrust can be effectively balanced by symmetrically arranged expansion stages. Additionally, axial turbines operate at lower rotational speeds, which effectively ensures rotor stability. This paper introduces a 100-kW axial CO2 turbine developed in our laboratory. It employs a configuration with dual expansion stage arranged two sides of the generator, while low-temperature CO2 exhaust gas and water are utilized for integrated active cooling. Experimental tests show that the turbine can effectively achieve the target power, with overall efficiency exceeding 68% at peak performance. During operation, bearing vibrations and temperature fluctuations of the bearings are also small, indicating a stable rotor shaft system. This research provides new insights for the development of small-scale CO2 turbines.

Presenting Author: Yurong Wang Tianjin University

Presenting Author Biography: Wang specializes in the aerodynamic design of supercritical CO2 (sCO2) axial turbine and machine learning for the testing results. He has participated in research on 15 kW, 80 kW, 100 kW, and 200 kW sCO2 turbines. Currently, he is dedicated to the efficient aerodynamic design and fluid-thermal-structural coupling analysis of MW-class sCO2 turbines.

Authors:

Yurong Wang Tianjin University
Xuan Wang Tianjin University
Zhiyong Zhang Tianjin University
Hua Tian University of Science and Technology of China