This paper presents a virtual model of a scroll compressor developed on the one-dimensional analysis software Simcenter Amesim^®. The model is semi-empirical: it needs some physical details of the modelled machine (e.g., the cubic capacity), but, on the other hand, it does not require the geometrical features of the spirals, so it needs experimental data to calibrate it. The model also requires rotational speed and the outlet temperature as boundary conditions. The model predicts the power consumption and the mass flow rate and considers leakages and mechanical losses. After the model presentation, this paper describes the test bench and the obtained data used to calibrate and validate the model. At last, the calibration process is described, and the results are discussed. The calculated values fit the experimental data also in extrapolation, despite the model is simple and performs calculations within 7 s. Due to these characteristics, the model is suitable for being used in a larger model as a sub-component.

This article presents a numerical model of an aeronautical hybrid electric propulsion system (HEPS) based on an energy method. This model is designed for HEPS with a total power of 100 kW in a parallel configuration intended for ultralight aircraft and unmanned aerial vehicles (UAV). The model involves the interaction between the internal combustion engine (ICE), the electric motor (EM), the lithium battery and the aircraft propeller. This paper also describes an experimental setup that can reproduce some flight phases, or entire missions, for the reference aircraft class. The experimental data, obtained by reproducing two different take-offs, were used for model validation. The model can also simulate anomalous operating conditions. Therefore, the tests chosen for the model validation are characterized by the EM flux weakening (“de-fluxing”). This model is particularly suitable for preliminary stages of design when it is necessary to characterize the hybrid system architecture. Moreover, this model helps with the choice of the main components (e.g., ICE, EM, and transmission gear ratio). The results of the investigation conducted for different battery voltages and EM transmission ratios are shown for the same mission. Despite the highly simplified model, the average margin of error between the experimental and simulated results was generally under 5%.

The paper deals with the analysis of the compression stroke in rotary displacement compressors, following an innovative approach. Both a theoretical study and an experimental activity have been carried out to achieve the results.\ud \ud The rotary compressors are positive displacement machines in which compression and displacement are affected by the positive action of rotating elements. Currently, these machines are successfully employed in many applications, such as refrigeration, heat pumps and supercharged automotive engines. The first step of the activity presented in this paper has been the analysis (also in terms of bibliographical research) of the well-known theory behind the operation of the rotary compressors, in order to clarify the correct ideal working process. The main finding has been the evaluation that the use of the classical “pV representation” to calculate the ideal specific work leads to a numerical error in the result. In order to overcome the miscalculation, the authors have proposed a different representation of the process, introducing a new approach and a consistent model. Starting from the new pV representation, a more detailed equation has been achieved to calculate a more exact value of the ideal specific work. After the theoretical analysis, a test bench has been set up, in order to compare the developed model with experimental data: particularly, the machine object of test has been a scroll compressor. The specific work has been evaluated for the scroll compressor, tested under different working conditions, (for example, at different compression ratios): the values have been successfully compared with the theoretical ones, previously calculated by the new equation.\ud \ud An optimistic conclusion is represented by the good agreement of the new proposed model with the experimental data, while it is still simple, adaptable, and theoretically strict