Experimental Research of Thermal-Flow and Vibration Characteristics of A 1 kw ORC Microturbine

This paper discusses the experimental research findings on a high-speed microturbine in an ORC system using the low-boiling fluid HFE-7100. The microturbine prototype features a hermetic design and was developed using oil-free technology, incorporating gas bearings powered by a low-boiling fluid. One of the main objectives of the study was to determine the thermodynamic parameter ranges within which the microturbogenerator could operate correctly. Tests of the microturbine were conducted within a rotational speed range of 10,000 rpm to approximately 75,000 rpm, with receiver loads ranging from 200 W_e to 2,000 W_e. The power of the heat source and the flow rate of the HFE-7100 working fluid ranged from 12 to 20 kWt and 30 to 60 g/s, respectively. The chosen range of heat source power was deliberate and simulated the actual operating conditions of domestic boilers. In addition to measurements of thermal, flow, and energy parameters, vibration measurements of the turbogenerator were carried out to assess the dynamic state of the machine. The study found that for each power level of the heat source, the optimum generator load was determined at which the electrical output of the system reached its maximum. The work includes the electrical and dynamic characteristics of the high-speed microturbogenerator.