Optimal Engine Components

Application of new technologies and development of new design concepts for key engine components will be the source of improved engine performance and operating efficiency. Optimal design solution for high-pressure compressor with the pressure ratio between 9,5-10 combined with cooled turbine technology supported by efficient combustion chamber can deliver requested efficiency improvement. The new design concepts of engine components optimized for small engine operation will significantly contribute to the low fuel consumption and longer maintenance intervals. ESPOSA will directly benefit from results and data gained by CESAR to find optimal technologies and design solutions.

Optimal small compressor (WP2.1)
A compressor is one of the main engine components. A compressor optimization provides improvements of the whole propulsion system performance parameters: specific fuel consumption, reliability, lifetime, emissions, weight and minimal production costs.  Investigations in the CESAR project showed that efficiency for the compressor pressure ratio higher than 10 will not be balanced by accompanied economic effects for this distinctive engine power class. For BE2 platform ESPOSA will go beyond state-of-the-art compressor level of efficiency (adiabatic efficiency will be no less than 0.82) and total pressure ratio (not less than 9.5:1). The aim is also to increase the component reliability and to get centrifugal compressor weight reduction. The RTD work will also focus on  optimized compressor (engine) inlet design solutions to provide higher propulsive system efficiency and safety centrifugal compressor surge control (surge margin). The development of advanced casing treatments and mechanical active clearance control for centrifugal compressor will be also part of the work. For BE1 compressor technologies will focus mainly on low-cost manufacture technologies.

Advanced cooled small turbine (WP2.2)
The ESPOSA project plans a higher than state-of-the-art turbine performance for a small engine (BE2) to be achieved through a high level of efficiency (0.84), high inlet turbine temperature level (1430-1500K), high reliability, and low weight (-10%). This will be accomplished through development of an optimal cooling system and an optimized turbine rotor-stator clearance system, use of knowledge gained from combustor-turbine unsteady interaction investigations, and through advanced multi-objective and multidisciplinary optimization methods developed in the CESAR project. A new optimized small turbine will be designed and tested. The optimized small turbine will provide higher propulsive system efficiency (+7%). A new simple cooling technology for BE1 platform will be developed for vanes of small turbines to prolong the lifetime of vanes and turbine blades. This new technology will be based on cooling film from a slot at the leading edge on the vane forming a thermal barrier covering the complete vane surface.

Efficient combustion concept (WP2.3)
The objective is to develop and experimentally prove a new optimal combustion concept for BE1 platform with respect to requirements for low manufacturing costs, high combustion efficiency, exit temperature distribution, reliability and durability. The aim is to tailor and validate potential of two combustions systems – the first is an optimized conventional RQL (Rich burn - quick Quench - Lean burn) and the second more technically risky combustion JETIS concept. JETIS (JET Induced Swirl) concept was developed at VZLU during national project, this concept promises higher reduction of combustor complexity for small gas turbines while maintaining efficient and stable combustion. However, a lot of research and validation work is necessary to prove JETIS concept before it can be integrated into engine test bench. Design of optimal combustor shape and air passages arrangement maximizes effective use of given combustor volume and provide efficient and reliable combustion in highly loaded BE1 combustor, with use of TBC (Thermal Barrier Coating) protection, modern simulation and experimental techniques.

Optimal gear box design (WP2.4)
Limited confidence in the prediction of the dynamic loads generated in a transmission is a major reason to oversize and/or reduce manufacturing tolerances on components (mainly gears). The main challenge is to properly model all interactions of several transmission components and to simulate the excitation due to the gear meshes. Modern analysis tools allow simulating complex systems but the mesh excitation modelling remains a key research area to improve the quality of the predicted outputs. This will be achieved by a thorough calibration of advanced models with experimental data. The engine noise emissions caused by power transmissions is of increasing importance as the other engine modules are continuously improved in terms of noise emissions. Development and calibration of advanced noise predicting modelling techniques are necessary for further improvement of noise optimized gearbox design.

Advanced dynamic modelling of high speed turbomachinery (WP2.5)
Engine producers showed significant need for development of an advanced rotordynamic model of a GTE rotor system. Such a model will be used for a comprehensive assessment of GTE rotordynamics – critical speeds, mode shapes, critical speed map, stability evaluation, unbalance responses, and special events.  Various special dynamic topics such as blade loss, blade-housing interference, non-synchronous excitation will be addressed. The planned work will comprise development of propeller dynamic model methodology used for investigation of coupled propeller and engine vibration models. This work is a logic completion of RTD activities on the optimal engine components area.

Enhanced mathematical modeling of gas turbine engines (WP1.3)
ESPOSA will support the engine manufacturer with enhanced tools and modeling capabilities for gas turbine engines to perform trade-off studies for any new propulsions systems more effectively (less time consuming and more accurate). The goal is to provide improved tools and models to improve the time and quality of the analysis which can provide crucial data to the design engineers about potential improvement possibilities in the engine configuration, architecture and performance.  The base for innovation will be the available and widely used Gasturbine Simulation Program (GSP) which will be further improved by its authors with respect to dynamic behaviour of the whole engine system.