The detailed exploration of the axial MM turbine within the DExpand project’s 2023 timeline reached its manufacturing, assembly and commissioning. Initial evaluations were conducted using air as a working medium, serving as a preliminary step to ascertain the turbine’s operational integrity and baseline performance metrics. This phase was crucial for identifying initial performance characteristics and ensuring that the turbine’s design could withstand the conditions of more rigorous testing environments. Unfortunately mechanical vibrations at higher speeds limited the operation range and prompted a modification in the design.
Subsequent tests transitioned to the MM ORC test rig, the intended operational environment. The vibrations and potential risks limited achievement of a full speed, confirming concerns from the air tests. Regardless, the test was very valuable to confirm other design aspects regarding mechanical integration, sealing, control and electrical output interconnection and generally applicability of a high speed machining motor as a readily available high speed turbine generator (after compatibility measures). See below the results from the air and ORC MM tests.
The project’s focus on rotordynamics for the modified turbine and implementation of the desing resulted in modified configuration as shown in figure below.