Conceptual design study of a geared turbofan and an open rotor aero engine with intercooled recuperated core

2018 ◽  
Vol 232 (14) ◽  
pp. 2713-2720 ◽  
Author(s):  
C Salpingidou ◽  
D Misirlis ◽  
Z Vlahostergios ◽  
M Flouros ◽  
F Donus ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Specific Fuel Consumption ◽  
Pollutant Emissions ◽  
Low Thrust ◽  
Tubular Heat Exchanger ◽  
Work Demand ◽  
High Pressure Compressor ◽  
Aero Engine ◽  
Open Rotor ◽  
Aero Engines

The development of more efficient aero engines is becoming a matter of great importance due to the need for pollutant emissions reduction (e.g. CO2, NOx). Toward this direction, two of the most promising aero engine architectures that have been proposed are the ultrahigh by-pass geared turbofan and the open rotor configurations, both of which are targeting the low thrust-specific fuel consumption and reduced NOx production. In the current study, investigations are performed in order to determine the improvements in thrust-specific fuel consumption for these configurations. More specifically, on the basic geared turbofan and open rotor configurations an intercooler and a recuperator are implemented between the compressors and the exhaust nozzle, respectively. The intercooler is installed in order to reduce the high pressure compressor work demand, while the recuperator is used in order to preheat the compressor discharge air by exploiting the otherwise wasted increased enthalpy content of the exhaust hot gas. The recuperator consists of elliptically profiled tubes and its design is based on the innovative tubular heat exchanger core arrangement that has been invented and developed by MTU Aero engines AG. The intercooled recuperative geared turbofan is evaluated against a nonintercooled recuperative geared turbofan, while the intercooled recuperative open rotor is evaluated against a nonintercooled recuperative open rotor. The results showed that the implementation of intercoolers and recuperators can further improve specific fuel consumption and can also lead to NOx emission reduction.

Design Optimization of Heat Exchangers for Aero Engines With the Use of a Surrogate Model Incorporating Performance Characteristics and Geometrical Constraints

2018 ◽  
Author(s):  
Christina Salpingidou ◽  
Dimitrios Misirlis ◽  
Zinon Vlahostergios ◽  
Michael Flouros ◽  
Fabian Donus ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Surrogate Model ◽  
Design Space ◽  
Specific Fuel Consumption ◽  
Performance Characteristics ◽  
Tubular Heat Exchanger ◽  
Geometrical Features ◽  
Aero Engine ◽  
Geometrical Constraints ◽  
Aero Engines

The present work is focused on the optimization of the performance characteristics of a recuperator specifically designed for aero engine applications, targeting the reduction of specific fuel consumption and taking into consideration aero engine geometrical constraints and limitations. The recuperator design was based on the elliptically profiled tubular heat exchanger which was developed and invented by MTU Aero Engines AG. For the specific fuel consumption investigations the Intercooled Recuperated Aero engine cycle, combining both intercooling and recuperation, was considered. The optimization was performed with the development of a recuperator surrogate model, capable to incorporate major recuperator geometrical features. A large number of recuperator design scenarios was assessed, in which additional design criteria and constraints were applied. Thus, a significantly large recuperator design space was covered resulting to the identification of feasible recuperator designs providing beneficial effect on the Intercooled Recuperated Aero engine leading to reduced specific fuel consumption and weight.

Thermodynamics Cycle Analysis, Pressure Loss and Heat Transfer Assessment of a Recuperative System for Aero Engines

2014 ◽  
Author(s):  
A. Goulas ◽  
S. Donnerhack ◽  
M. Flouros ◽  
D. Misirlis ◽  
Z. Vlahostergios ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Fuel Consumption ◽  
Heat Exchangers ◽  
Engine Performance ◽  
Specific Fuel Consumption ◽  
Hot Gas ◽  
Research Activities ◽  
Aero Engine ◽  
Overall Efficiency ◽  
Aero Engines

Aiming in the direction of designing more efficient aero engines, various concepts have been developed in recent years, among which is the concept of an intercooled and recuperative aero engine. Particularly in the area of recuperation, MTU Aero Engines has been driving research activities in the last decade. This concept is based on the use of a system of heat exchangers mounted inside the hot-gas exhaust nozzle (recuperator). Through the operation of the system of heat exchangers, the heat from the exhaust gas, downstream the LP turbine of the jet engine is driven back to the combustion chamber. Thus, the preheated air enters the engine combustion chamber with increased enthalpy, providing improved combustion and by consequence, increased fuel economy and low-level emissions. If additionally an intercooler is placed between the compressor stages of the aero engine, the compressed air is then cooled by the intercooler thus, less compression work is required to reach the compressor target pressure. In this paper an overall assessment of the system is presented with particular focus on the recuperative system and the heat exchangers mounted into the aero engine’s exhaust nozzle. The herein presented results were based on the combined use of CFD computations, experimental measurements and thermodynamic cycle analysis. They focus on the effects of total pressure losses and heat exchanger efficiency on the aero engine performance especially the engine’s overall efficiency and the specific fuel consumption. More specifically, two different hot-gas exhaust nozzle configurations incorporating modifications in the system of heat exchangers are examined. The results show that significant improvements can be achieved in overall efficiency and specific fuel consumption hence contributing into the reduction of CO2 and NOx emissions. The design of a more sophisticated recuperation system can lead to further improvements in the aero engine efficiency in the reduction of fuel consumption. This work is part of the European funded research program LEMCOTEC (Low Emissions Core engine Technologies).

Development, Numerical Investigation and Experimental Validation of a New Recuperator Design for Aero Engines Applications

2017 ◽  
Author(s):  
Zinon Vlahostergios ◽  
Dimitrios Misirlis ◽  
Michael Flouros ◽  
Christina Salpingidou ◽  
Stefan Donnerhack ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Waste Heat ◽  
External Pressure ◽  
Pollutant Emissions ◽  
Pressure Losses ◽  
Low Pressure Turbine ◽  
Heat Exchanger Design ◽  
Aero Engine ◽  
Pollutants Emission ◽  
Aero Engines

Targeting the development of more efficient aero engine designs, various concepts have been considered through the previous years, among which is the Intercooled Recuperative Aero engine (IRA) concept. In the IRA concept a system of heat exchangers is mounted in the hot-gas exhaust nozzle, downstream of the low-pressure turbine focusing on the exploitation of the waste heat exhaust gasses for preheating the compressor discharge air just before the latter enters the combustion chamber, resulting in fuel consumption and pollutants emission reduction. In the present work a new heat exchanger design for use as a recuperator is proposed for possible implementation in the IRA engine, based on an annular configuration design which is more easily integrated in an aero engine. The new recuperator external pressure losses are computationally and experimentally investigated for laboratory conditions, providing very good agreement. Additionally, the pressure losses just before the recuperator were further minimized by introducing riblet films inside the exhaust conical nozzle. The optimized recuperator characteristics were included in a thermodynamic analysis of the IRA engine and it was shown that considerable improvement in fuel consumption and pollutant emissions reduction could be achieved.

Intercooler Parametric Analysis for the IRA Engine Cycle Performance Augmentation

2021 ◽  
Author(s):  
Emmanouil Alexiou ◽  
Zinon Vlahostergios ◽  
Christina Salpingidou ◽  
Fabian Donus ◽  
Dimitrios Misirlis ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Fuel Consumption ◽  
Heat Exchangers ◽  
High Efficiency ◽  
Specific Fuel Consumption ◽  
Cycle Performance ◽  
Tubular Heat Exchanger ◽  
Aero Engine ◽  
Pressure Compressor ◽  
Engine Cycle

Abstract Aiming in the direction of designing high efficiency aircraft engines, various concepts have been developed in recent years, among which is the concept of the intercooled and recuperative aero engine (IRA engine). This concept is based on the use of a system of heat exchangers (recuperator) mounted inside the hot-gas exhaust nozzle, as well as a system of heat exchangers (intercooler) mounted between the intermittent-pressure compressor (IPC) and the high-pressure compressor (HPC) compressor modules. Through the operation of the system of recuperator module, the heat from the exhaust gas, downstream the LP turbine of the aero engine is driven back to the combustion chamber. Thus, the preheated air enters the engine combustion chamber with increased enthalpy, providing higher combustion efficiency and consequently reduced thrust specific fuel consumption (TSFC) and low-level emissions. Additionally, by integrating the intercooler module between the compressor stages of the aero engine, the compressed air is cooled, leading to less required compression work to reach the compressor target pressure and significant improvements can be achieved in the overall engine efficiency and the specific fuel consumption hence, contributing to the reduction of CO2 and NOx emissions. The present work is focused on the optimization of the performance characteristics of an intercooler specifically designed for aero engine applications, working cooperatively with a novel design recuperator module targeting the reduction of specific fuel consumption and taking into consideration aero engine geometrical constraints and limitations for two separate operating scenarios. The intercooler design was based on the elliptically profiled tubular heat exchanger which was developed and invented by MTU Aero Engines AG. For the specific fuel consumption investigations, the Intercooled Recuperated Aero engine cycle that combines both intercooling and recuperation was considered. The optimization was performed with the development of an intercooler surrogate model, capable to incorporate major geometrical features. A large number of intercooler design scenarios was assessed, in which additional design criteria and constraints were applied. Thus, a significantly large intercooler design space was covered resulting to the identification of feasible designs providing beneficial effect on the Intercooled Recuperated Aero engine performance leading to reduced specific fuel consumption, reduced weight and extended aircraft range.

Multidisciplinary Analysis of a Geared Fan Intercooled Core Aero-Engine

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Konstantinos G. Kyprianidis ◽  
Andrew M. Rolt ◽  
Tomas Grönstedt
Keyword(s):  
Exchange Rates ◽  
Fuel Consumption ◽  
Pressure Ratio ◽  
Velocity Ratio ◽  
Specific Fuel Consumption ◽  
Design Parameters ◽  
Aircraft Model ◽  
Aero Engine ◽  
Jet Velocity ◽  
Analytical Expressions

The reduction of CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, along with the reduction of engine nacelle drag and weight. One alternative design approach to improving specific fuel consumption is to consider a geared fan combined with an increased overall pressure ratio intercooled core performance cycle. The thermal benefits from intercooling have been well documented in the literature. Nevertheless, there is very little information available in the public domain with respect to design space exploration of such an engine concept when combined with a geared fan. The present work uses a multidisciplinary conceptual design tool to analyze the option of an intercooled core geared fan aero engine for long haul applications with a 2020 entry into service technology level assumption. With minimum mission fuel in mind, the results indicate as optimal values a pressure ratio split exponent of 0.38 and an intercooler mass flow ratio of 1.18 at hot-day top of climb conditions. At ISA midcruise conditions a specific thrust of 86 m/s, a jet velocity ratio of 0.83, an intercooler effectiveness of 56%, and an overall pressure ratio value of 76 are likely to be a good choice. A 70,000 lbf intercooled turbofan engine is large enough to make efficient use of an all-axial compression system, particularly within a geared fan configuration, but intercooling is perhaps more likely to be applied to even larger engines. The proposed optimal jet velocity ratio is actually higher than the value one would expect by using standard analytical expressions, primarily because this design variable affects core efficiency at mid-cruise due to a combination of several different subtle changes to the core cycle and core component efficiencies at this condition. The analytical expressions do not consider changes in core efficiency and the beneficial effect of intercooling on transfer efficiency, nor do they account for losses in the bypass duct and jet pipe, while a relatively detailed engine performance model, such as the one utilized in this study, does. Mission fuel results from a surrogate model are in good agreement with the results obtained from a rubberized-wing aircraft model for some of the design parameters. This indicates that it is possible to replace an aircraft model with specific fuel consumption and weight penalty exchange rates. Nevertheless, drag count exchange rates have to be utilized to properly assess changes in mission fuel for those design parameters that affect nacelle diameter.

Multidisciplinary Assessment of the Control of the Propellers of a Pusher Geared Open Rotor—Part II: Impact on Fuel Consumption, Engine Weight, Certification Noise, and NOx Emissions

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Pablo Bellocq ◽  
Inaki Garmendia ◽  
Vishal Sethi ◽  
Alexis Patin ◽  
Stefano Capodanno ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Full Range ◽  
Low Pressure ◽  
Performance Model ◽  
Preliminary Design ◽  
Fuel Saving ◽  
Low Thrust ◽  
Regulatory Constraints ◽  
Open Rotor ◽  
The Impact

Due to their high propulsive efficiency, counter-rotating open rotors (CRORs) have the potential to significantly reduce fuel consumption and emissions relative to conventional high bypass ratio turbofans. However, this novel engine architecture presents many design and operational challenges both at engine and aircraft level. The assessment of the impact of the main low-pressure preliminary design and control parameters of CRORs on mission fuel burn, certification noise, and emissions is necessary at preliminary design stages in order to identify optimum design regions. These assessments may also aid the development process when compromises need to be performed as a consequence of design, operational, or regulatory constraints. Part I of this two-part publication presents a novel 0D performance model for counter-rotating propellers (CRPs) allowing an independent definition of the design and operation of each of the propellers. In Part II, the novel CRP model is used to create an engine performance model of a geared open rotor (GOR). This engine model is integrated in a multidisciplinary simulation platform which was used to assess the impact of the control of the propellers, on specific fuel consumption (SFC), engine weight, certification noise, and NOx emission, for a GOR with a 10% clipped rear propeller designed for a 160 PAX and 5700 NM aircraft. The main conclusions of the study are: (1) Minimum SFC control schedules were identified for climb, cruise, and descent (high-rotational speeds for high thrust and low-rotational speeds for low thrust), (2) SFC reductions up to 2% in cruise and 23% in descent can be achieved by using the minimum SFC control. However, the relatively high SFC reductions in descent SFC result in ∼3.5% fuel saving for a 500 NM and ∼0.7% fuel saving for a full range mission, (3) at least 2–3 dB noise reductions for both sideline and flyover can be achieved by reducing the rotational speeds of the propellers at a cost of ∼6% increase of landing and takeoff cycle (LTO) NOx and 10 K increase in turbine entry temperature, (4) approach noise can be reduced by at least 2 dB by reducing CRP rotational speeds with an associated reduction of ∼0.6% in LTO NOx, and (5) the control of the CRP at takeoff has a large impact on differential planetary gearbox (DPGB) weight, but it is almost identical in magnitude and opposite to the change in low-pressure turbine (LPT) and CRP weight. Consequently, the control of the CRP at takeoff has a negligible impact in overall engine weight.

Multi-Disciplinary Analysis of a Geared Fan Intercooled Core Aero-Engine

2013 ◽  
Author(s):  
Konstantinos G. Kyprianidis ◽  
Andrew M. Rolt ◽  
Tomas Grönstedt
Keyword(s):  
Exchange Rates ◽  
Fuel Consumption ◽  
Pressure Ratio ◽  
Velocity Ratio ◽  
Specific Fuel Consumption ◽  
Design Parameters ◽  
Aircraft Model ◽  
Aero Engine ◽  
Jet Velocity ◽  
Analytical Expressions

Reduction of CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, as well as the reduction of engine nacelle drag and weight. One alternative design approach to improving specific fuel consumption is to consider a geared fan combined with an increased overall pressure ratio intercooled core performance cycle. Thermal benefits from intercooling have been well documented in the literature. Nevertheless, there is very little information available in the public domain with respect to design space exploration of such an engine concept when combined with a geared fan. The present work uses a multidisciplinary conceptual design tool to analyse the option of an intercooled core geared fan aero engine for long haul applications with a 2020 entry into service technology level assumption. With minimum mission fuel in mind, the results indicate as optimal values a pressure ratio split exponent of 0.38 and an intercooler mass flow ratio just below 1.2 at hot-day top of climb conditions. At ISA mid-cruise conditions a specific thrust of 86m/s, a jet velocity ratio of 0.83, an intercooler effectiveness of 55% and an overall pressure ratio value of 76 are likely to be a good choice. A 70,000lbf intercooled turbofan engine is large enough to make efficient use of an all-axial compression system, particularly within a geared fan configuration, but intercooling is perhaps more likely to be applied to even larger engines. The proposed optimal jet velocity ratio is actually higher than the value one would expect by using standard analytical expressions primarily because this design variable affects core efficiency at mid-cruise due to a combination of several different subtle changes to the core cycle and core component efficiencies at this condition. Analytical expressions do not consider changes in core efficiency and the beneficial effect of intercooling on transfer efficiency, nor account for losses in the bypass duct and jet pipe, whilst a relatively detailed engine performance model such as the one utilised in this study does. Mission fuel results from a surrogate model are in good agreement with the results obtained from a rubberised-wing aircraft model for some of the design parameters. This indicates that it is possible to replace an aircraft model with specific fuel consumption and weight penalty exchange rates. Nevertheless, drag count exchange rates have to be utilised to properly assess changes in mission fuel for those design parameters that affect nacelle diameter.

Advanced Aero-Engines Technology Enablers: An Overview of the European Project E-BREAK

2016 ◽  
Author(s):  
Manuel Silva ◽  
Nicolas Tantot ◽  
Serge Selezneff ◽  
Mike Walsh ◽  
Rose Nyatando ◽  
...  
Keyword(s):  
Global Market ◽  
Air Travel ◽  
Air Traffic ◽  
Pollutant Emissions ◽  
Aviation Industry ◽  
Component Level ◽  
Average Growth ◽  
Enabling Technologies ◽  
Aero Engine ◽  
Aero Engines

This paper describes research carried out in the European Commission co-funded project E-BREAK (Engine BREAK through components and subsystems) focused on development of generic enabling technologies for new aero-engines. A global market forecast (2015–2034) from Airbus [1], depicts an average growth rate of 4.6% per year. Air traffic is forecasted to double in the next 15 years. It is expected, to triple in the next 20 years, according to the speech given by RRUK CEO during the Aerodays 2015 in London [2]. This high level of growth in demand for air travel represents huge opportunities as well as significant challenges for the aerospace industry. Research and Technology through collaborative European projects addresses the environmental penalties of air traffic. Europe’s aviation industry therefore faces a huge challenge to satisfy the demand whilst guaranteeing competitiveness, safety and more environmentally friendly air travel. Innovative engine configurations consequently need to be investigated in order to reduce significantly the pollutant emissions (15 to 20% for fuel consumption and CO2 and 80% reduction for NOx). Such reductions can only be achieved by considering innovative components that could be integrated and optimized in new engine configurations. In response to the above demands, aero-engine manufacturers are constantly aiming to improve gas turbine efficiency for two main reasons: to reduce environmental impact and to minimize operating costs. The E-BREAK project is aimed at the development of generic enabling technologies needed to address the challenges for future engines with higher overall pressure ratios (OPR) and bypass ratio (BPR). These technologies are developed at subsystem and component level and validated in test rigs which are equivalent to Technical Readiness Level (TRL) 5. The utility of the developed technologies are assessed using four standard study powerplants. These are turboshaft, regional turbofan, mid-size open rotor, and large turbofan, covering most of the expected future commercial aero-engine market. This article describes the technical approach followed in E-BREAK for the various technologies being investigated, these are: • Advanced sealing to reduce oil and air leakages • Variability control to ensure stability of thermodynamic cycle • High temperature resistant material and abradables to prevent fast degradation at high temperatures • Light material to prevent significant mass increase • Health monitoring system to anticipate sub-systems degradation The envisaged outcomes from E-BREAK are enablers to other EU-funded research projects focused on module maturation progress, such as LEMCOTEC dealing with high OPR modules and ENOVAL dealing with high BPR LP components.

Air-Cooled Engines in Service

1929 ◽  
Vol 33 (220) ◽  
pp. 269-318
Author(s):  
A. H. R. Fedden
Keyword(s):  
Fuel Consumption ◽  
The Sun ◽  
Oil Consumption ◽  
Missionary Work ◽  
The Past ◽  
New Family ◽  
Aero Engine ◽  
Aero Engines ◽  
The Way

It is now rather more than three years since I last had the honour of presenting a paper before this Society dealing with air-cooled aero engines. At that time the air-cooled engine had not fully won a place “in the sun,” which may be fairly stated to be the case to-day.For some years after the war there was a considerable aversion towards the air-cooled aero engine owing to certain types which had been developed during the war which were supposedly air-cooled, but in reality obtained the greater portion of their cooling by means of exorbitant fuel and oil consumption. As lately as four years ago the practical advantages of the air-cooled engine were only tentatively appreciated by the aircraft constructor, and naturally, owing to his somewhat painful experiences in the past in respect of unreliability and high fuel consumption; it required some missionary work and proof in order to persuade him that the new family of air-cooled engines would really perform in the way their designers claimed for them.

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