Numerical and experimental investigation of different technologies for adjusting the swallowing capacity of a cantilever ORC turbine Available to Purchase

Waste Heat Recovery at industrial processes becomes more and more important. The thermal profiles in these processes undergo high fluctuations, which pose a problem for downstream Organic Rankine Cycles. A possibility to cope with this circumstance is the implementation of storages or intermediate cycles, but in this paper, a different approach is followed. The ORC conditions should be kept constant by means of an adaptable turbine geometry. The present publication deals with the investigation of two different technologies to adjust the swallowing capacity of a cantilever ORC turbine - rotatable nozzle ring (RNR) and adjustable nozzle height (ANH). The considerations were performed on a reference turbine using pressurized air as working fluid. But a transfer of the findings to ORC application is reasonable. By performing comprehensive CFO analysis of the two technologies, the ANH technology was found to be superior. This is why a prototype of this technology was built and tested on a pressurized air test rig. Only small deteriorations of the total-to-static turbine efficiency at 50% design mass flow rate were observed. Based on this result, a ORC prototype of the ANH technology will be tested in future.