Advanced SAW-sensor technology for sustainable energy systems including wireless transponder and communication technology
In cooperation with partners in research and industry, the research project "SAWES" aims to develop a mobile, wireless and heat-resistant temperature sensor system
based on SAW (Surface Acoustic Wave) sensors. The SAW sensors allow precise measurements without relying on an external power supply.
The wireless data transmission enables the sensors to be used in areas difficult to access, such as moving or concealed positions and simplifies the application
compared to wired systems. The intended field of application is provided for sustainable energy supply systems and energy-efficient consumers in industry, trade, commerce
and services, thus making a significant contribution to the development and monitoring of the systems.
B&B-AGEMA's responsibility within this project is the development of a suitable test bench and the execution of tests. They are intended to verify the application
of the measuring system in environmental conditions comparable to the usage in gas turbines and engines.
Project partners:
Anwendungsmöglichkeiten in der Industriegasturbine:
Project details:
The operation of a SAW System is based on the propagation of surface acoustic waves (SAW), generated by an interdigital transducer via the inverse piezoelectric effect
on the surface of a piezoelectric substrate. Already existing systems based on this technology are limited to a temperature range from - 55 °C to approx. 350 °C.
This temperature range is to be extended to > 400°C, by using a relatively new piezoelectric monocrystal material. The system will be tested in dynamic applications
up to 600 °C and in static applications up to 900 °C. Unlike established materials like LiNbO3, LiTaO3 or quartz, the new material allows operating temperatures of up to 900 °C,
with simultaneously higher piezoelectric coefficients. The autonomous operation of the sensors (without power supply) as well as the low response times and the wireless data transmission
allow the system to be used even on dynamic and concealed components.
An essential part of the research project is the development of a suitable test rig for evaluation of the measuring system under extreme environmental conditions,
comparable to those in industrial gas turbines. The focus is the application on rotating components, such as the outlet of the compressor rotor, turbine components and in the sealing air system.
In addition to high centrifugal acceleration, the sensors are exposed to high temperatures of up to 1000 °C. The use of sensors in these areas can help to improve industrial gas turbines
in terms of their quick start characteristics, component life and cooling air consumption in the following ways:
Fast ramp-up and shut-down processes lead to high stresses in the components and thus to a reduced service life. The monitoring of temperatures at critical components,
such as in the compressor as well as compressor outlet is therefore of great importance. In combination with state-of-the-art calculation methods, design improvements can be realized,
which allow faster start-up and shut-down as well as a more flexible operation.
The temperature of individual components is related to their efficiency and occurring effects of aging. The determined time-dependent data of the sensors can be used for
long-term monitoring in tools like GTPtracker, e.g. to optimize maintenance schedules and reduce downtimes.
An exact determination of the component temperature allows for a reduction of safety factors, making optimal use of material properties (e.g. thermal load capacity)
and thus saving cooling air. Furthermore a draw in of hot air or a large sealing air flow can be monitored in the sealing air system.
Since these air flows do not participate in the combustion process, an optimization of the process air also has a positive effect on the overall efficiency of the turbine.
Process Development for the Fabrication of FeAl-Components for Combined Cycle Power Plants;
Sub-Project: Material-related Component Design
Within the scope of the collaborative research project “FeAl-GuD”, which is funded by the Federal Ministry for Economic Affairs
and Energy (BMWi), an intermetallic phase of iron and aluminium (FeAl) should be made available for power plant technology.
Iron aluminides besides titanium aluminides belong to the most important intermetallic materials with high application potential
as high-temperature materials.
B&B-AGEMA is focused on the aerodynamic and structural design of turbine bladings made of iron aluminides.
Project partners:
Application-oriented parts of a Combined Cycle Power Plant (CCPP):
Project details:
Combined cycle power plants (CCPP) optimally suite the task of grid stabilisation in terms of the electricity supply as part
of the planned expansion of the renewable energies. CCPPs are characterised by short start-up and shutdown times, fast load changes
and a comparatively high efficiency.
The last gas turbine stages usually are manufactured from nickel-base alloys and the first stages of high and intermediate pressure
steam turbines mainly are made of high-alloyed heat-resistant steels. The application of an intermetallic phase of iron and aluminium
(FeAl) yields the possibility for closing the gap in terms of the operating temperature among heat-resistant steels (operating
temperature up to approx. 620 °C) and nickel-base alloys (operating temperature from approx. 700 °C). This enables an enhanced
thermodynamic process control in CCPPs by increasing the gas turbine outlet temperature and the corresponding live steam temperature
of the bottoming cycle. Hereby, the thermal process efficiency can be further improved whilst achieving a target quantity of 65 %.
Iron Aluminides offer a series of positive characteristics:
high heat resistance in the range of 600 – 700 °C
excellent corrosion and erosion resistance
approx. 12 – 18 % lower density as steel, approx. 16 – 20 % lower density as Nickel-base alloys
low material costs
simple manufacturability
long-term availability, since sparsely / no use of strategic elements (rare earths)
completely recyclable
Lower density and improved material properties of FeAl enable shortened start-up and shutdown times of gas and steam turbines
in contrast to the established materials as used in turbomachinery. The operational flexibility of CCPPs should be improved based on
lowered moving masses by usage of FeAl.
Another project objective of B&B-AGEMA is the increase of aerodynamic turbine efficiency as a result of further development of
flow-optimised blading geometry with reduced gap and secondary flow losses for outlet blading of the gas turbine and inlet blading of
the steam turbine in consideration of the service possibilities of the new material.
After casting iron aluminides develop a coarse grain structure during solidification, which results in a low ductility and an increased
susceptibility to cracking. On this account the casting process for the FeAl intermetallic compound should be improved by insertion of
nucleation agents in the melt and a fine grain structure is expected. This will reduce the susceptibility to cracking and increase the
room temperature ductility. Finally the mechanical behavior of the newly, grain refined FeAl material will be analysed and a database
with the relevant material properties of low and high cycle fatigue (LCF / HCF), thermomechanical fatigue (TMF) and creep and oxidation
properties will be established.
Research Project “HyFly”
Hybrid propulsion system for short-range aircraft
The overall goal of the HyFly project is the conceptual development of a hybrid electric propulsion system for the integration
into a regional aircraft. It is intended to significantly contribute to the objective of reducing emissions with respect to
pollutants and noise in aviation as defined in the European aviation vision “Flightpath 2050”.
This should be achieved by using hybrid drive architecture. The thrust is provided by electric motors. During the relatively short
starting phase of the aircraft, which is most demanding for the power system, the engines are assisted by a battery. During cruise,
the power is supplied by a reluctance generator, driven by a special gas turbine.
B&B-AGEMA focuses on the conceptual design of the gas turbine intended to drive the reluctance generator as well as the
development of software for analysis of the operation and prediction of the long-term behavior of the GT.
Project partners:
Research concept:
Project details:
Due to the scalability of electric motors without internal loss in efficiency, it is possible to design new aircraft configurations
with small span-spread, electrically driven propellers. This allows more efficient wing designs. The drive system to be developed
within the present project will feature distributed purely electric drives with a bivalent power supply; consisting of a battery pack
and a gas turbine with a directly coupled reluctance generator. This propulsion concept envisages that the high power required during
the relatively short starting phase of the hybrid aircraft is provided by an on-board battery, which can be charged on the ground
with electric energy obtained from renewable sources. During cruise, the aircraft's propulsion system is powered solely by an on-board
turbine generator system. Accordingly, the objective of reducing emissions is achieved in two ways: On the one hand, the portion of
energy to be extracted from fossil fuels is reduced by the amount that can be provided via renewable electricity; on the other hand,
an eminently high efficiency can be reached for the gas turbine, since cyclic loading is not required. The operation of the GT at
an optimized, very constant base load point allows the reduction of the fuel consumption and emissions.
One focus of the planned project is on the conceptual development of an in-flight power unit consisting of a high-performance
reluctance generator and a gas turbine. It is characterized by the first time use of a switched reluctance machine for power
generation for aircraft application. This type of generator operates very efficiently – especially at high rotational
speeds – which is ideal for coupling to a gas turbine of the required power class. The battery-electric system supports the take-off phase
and compensates quick load adjustment requirements. This reduces the rated output of the gas turbine compared to conventional drives
and allows operation of the GT a constant turbine inlet temperatures and rotation speed. Extreme operating points and high mechanical
and thermal stresses can be avoided. Thus, maintenance intervals can be extended and the overall life-time costs of the GT, reduced.
The generated power is delivered to e-aircraft engines, whose predevelopment according to the requirements of the overall system
analysis is also part of the project. With the system components to be examined, new aircraft and propulsion concepts can be realized.
The parallel integration of the models derived from the development of the new propulsion system components into the MICADO aircraft
preliminary design environment, makes it possible on the one hand to design aircraft concepts with this propulsion system and to
evaluate their operating costs, performance and eco-efficiency compared to existing reference aircraft. In the project HyFly a
Dornier Do228-212 is examined. As a result, it should also be possible to prove the development success and the potential of
hybrid-electric powered regional aircraft.
PERformance enhancement of
MIcro
Turbine based CHP systems
“PERMIT”
The collaborative research Project "Permit" has been performed in collaboration with Micro Turbine Technology (MTT),
Leuven Air Bearings and B&B-AGEMA and has been funded within the INTERREG program.
B&B-AGEMA investigated the heat management of the turbine and bearing assembly of the micro turbine ( the "hot part" of the
micro turbine) by application of the conjugate heat transfer method, a numerical method to determine the material temperature
distribution with simultaneous determination of the internal fluid flow fields and their mutual interactions. Based on the complex
simulation model the heat flow through several components of the turbine assembly and the influences of different flows could be
evaluated and the results could be used for optimization of the heat management and thus, for performance enhancement of the turbine.
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In cooperation with partners in research and industry, the research project "SAWES" aims to develop a mobile, wireless and heat-resistant temperature sensor system
based on SAW (Surface Acoustic Wave) sensors. The SAW sensors allow precise measurements without relying on an external power supply.
The wireless data transmission enables the sensors to be used in areas difficult to access, such as moving or concealed positions and simplifies the application
compared to wired systems. The intended field of application is provided for sustainable energy supply systems and energy-efficient consumers in industry, trade, commerce
and services, thus making a significant contribution to the development and monitoring of the systems.
One focus of the planned project is on the conceptual development of an in-flight power unit consisting of a high-performance
reluctance generator and a gas turbine. It is characterized by the first time use of a switched reluctance machine for power
generation for aircraft application. This type of generator operates very efficiently – especially at high rotational
speeds – which is ideal for coupling to a gas turbine of the required power class. The battery-electric system supports the take-off phase
and compensates quick load adjustment requirements. This reduces the rated output of the gas turbine compared to conventional drives
and allows operation of the GT a constant turbine inlet temperatures and rotation speed. Extreme operating points and high mechanical
and thermal stresses can be avoided. Thus, maintenance intervals can be extended and the overall life-time costs of the GT, reduced.
The generated power is delivered to e-aircraft engines, whose predevelopment according to the requirements of the overall system
analysis is also part of the project. With the system components to be examined, new aircraft and propulsion concepts can be realized.
The collaborative research Project "Permit" has been performed in collaboration with Micro Turbine Technology (MTT),
Leuven Air Bearings and B&B-AGEMA and has been funded within the INTERREG program.