The aim of this publication was to investigate the effects the blade count of a high-pressure centrifugal compressor’s impeller has on the performance of the DGEN 380 turbine engine at take-off. The study began with the development of a zero-dimensional thermo-fluid model of the engine. The model was matched with experimental data from the WESTT CS/BV virtual test bench for the baseline count and then implemented to analyse the engine behaviour at alternative counts. The corresponding changes in the compressor pressure ratio and efficiency were modelled in a commercial 3D CFD software and transferred to the zero-dimensional model with proper scaling. The results proved that the baseline design lied in the optimal range of thrust-specific fuel consumption. The increase in the blade count led to a crisis of the aerodynamic loading at the splitters, so that no further rise in the pressure ratio could be achieved. The results of the study could be implemented by mechanical engineers while solving the tasks of the maintenance and modernisation of gas turbines with radial compressors.

Current trends in the high bypass ratio turbofan engines development are discussed in the beginning of the paper. Based on this, the state of the art in the contemporary turbofan engines is presented and their change in the last decade is briefly summarized. The main scope of the work is the bypass ratio growth analysis. It is discussed for classical turbofan engine scheme. The next step is presentation of reach this goal by application of an additional combustor located between high and low pressure turbines. The numerical model for fast analysis of bypass ratio grows for both engine kinds are presented. Based on it, the numerical simulation of bypass engine increasing is studied. The assumption to carry out this study is a common core engine. For classical turbofan engine bypass ratio grow is compensated by fan pressure ratio reduction. For inter turbine burner turbofan, bypass grown is compensated by additional energy input into the additional combustor. Presented results are plotted and discussed. The main conclusion is drawing that energy input in to the turbofan aero engine should grow when bypass ratio is growing otherwise the energy should be saved by other engine elements (here fan pressure ratio is decreasing). Presented solution of additional energy input in inter turbine burner allow to eliminate this problem. In studied aspect, this solution not allows to improve engine performance. Specific thrust of such engine grows with bypass ratio rise – this is positive, but specific fuel consumption rise too. Classical turbofan reaches lower specific thrust for higher bypass ratio but its specific fuel consumption is lower too. Specific fuel consumption decreasing is one of the goal set for future aero-engines improvements.

This article presents a detailed approach to constructing a numerical model of a free power turbine engine specifically designed for performance analysis in the Matlab R2024b environment. The core innovation of this model lies in its integration of precise engine geometry parameters, calculated at the design point, and performance characteristics of key components such as the compressor and power turbine. These components are modeled to reflect significant variations in their performance based on changing operational conditions, including rotor speed and environmental factors. To validate the model’s assumptions, data from the PZL-3W engine were used. The model was created by meticulously incorporating the engine’s specific design characteristics, allowing for an in-depth examination of how performance characteristics shift with adjustments to high-pressure rotor settings or changes in ambient conditions. The resulting calculations demonstrated a high level of agreement between the model’s output and empirical data available for the PZL-3W engine, as well as with data found in the relevant scientific literature. This alignment underscores the model’s robustness and reliability in simulating engine performance across a range of operating scenarios, making it a valuable tool for further engineering analyses and optimization of free power turbine engines and their possible application.

The article presents a numerical investigation of the impact of heat exchanger (HE) location on the performance of the geared turbofan engine (GTF). It discusses the development trend for aero engines, with a primary focus on the modification of the turbofan engine cycle by the addition of the...