Measurement System of Small-Scale High Expansion Ratio ORC Turbine

Abstract

Small-scale and high temperature ORCs have received increasing interest in recent times. This type of power systems can have high expansion ratio turbines with gas dynamic effects differing significantly from the behaviour of ideal gases, as the turbines are often operated in the non-ideal dense-gas region. One of the most crucial steps leading to future improvement of turbine efficiency and to the development of design guidelines and loss analysis methods is to validate the applied design methods and loss correlations with experimental data. However, accurately measuring the performance of ORC turbines can be challenging. Indeed, despite the high pressure ratios, the temperature drop across the turbines remains rather low, and the physical size of turbomachinery tends to be small. In this paper, updates to the measurement system of the 10 kW LUT micro-ORC test-rig operating with siloxane MDM are presented. Further measurement points are placed at turbine inlet and outlet, and inside the turbine stator, with the aim of obtaining accurate performance maps and turbine loss analysis from future experimental runs.