FP 2

The GTF contains a gearbox between the fan and the LPT-Shaft, therefore the LPT & LPC can spin way faster than the fan. This improves the engine in multiple ways:

• The fan can spin slower, this improves TSFC

• The LPT & LPC can spin way faster and can be built lighter

• The fan spins slower -> lower noise

Geared Turbofan reduces:

- Noise footprint by 75%

- Fuel consumption and CO₂-emissions by 16%

- NOₓ-emissions by 50%

Aviation has gotten significantly safer over the decades.

Most accidents get caused by human error, only roughly 3% by engines

A climate metric has to meet several requirements due to the multitude of effects. Thus, not every one is suitable for aviation.

• The Average Temperature Response (ATR) describes the time integral of the change in the globally averaged temperature rise.

• Radiative forcing describes the difference between the energy reaching the atmosphere from space (solar radiation) and that emitted by the earth (infrared radiation).

Warm, moist exhaust gas stream (1) mixes with the cooler ambient air along a mixing line, ending up in ambient conditions (3 or 4).

Water in the exhaust gas cools and forms droplets on soot particles in the exhaust gas and particles present in the atmosphere,

provided that the mixing line intersects the saturation vapor pressure curve over water (2).

• If the ambient air is supersaturated with ice (3), the ice crystals do not sublime

→ persistent contrail

• If the ambient air is not supersaturated with ice (4.), the ice crystals sublime

→ non-persistent contrail

Persistent contrails can spread out and develop into contrail cirrus clouds

• Cooling of the Earth by reflecting incident short-wave solar radiation back into space (when the sun is high in the sky)

• Heating of the Earth by reflecting outgoing long-wave radiation back to earth (at night and when the sun is low)

• Warming of the atmosphere by absorption of solar energy

H2-Gaseous:

• Very low volumetric energy density

  -> Big tanks, high drag, less space for cargo

• Good gravimetric energy density

H2-Liquid:

• Better volumetric energy density

• Good gravimetric energy density

• LH2 ~2x more expensive than kerosene

• Hydrogen has potential to lower cost long-term but comes with high cost for infrastructure

SAF:

• HEFA or Power to liquid (Almost the entire volume of SAF available today is produced by the HEFA process)

• 50/50 Blend currently approved

• With current seals and piping SAF stills needs aromatics to be added

• Will be more expensive than fossil kerosene, even in the long term

• SAF ~3x more expensive than kerosene

Battery:

• Very low gravimetric energy density

• Not suitable for long range aircraft anytime soon

• Only suitable for niche aircraft

Carbon capture:

• Direct-Air-Capture (DAC)

• Co2 from point sources

• Only one third are Co2 effects

• Roughly 3% of the total emitted co2, is emitted by airplanes

• Most of the climate impact comes from non-co2 effects

• Co2 can be reduced by the (classical) measure of reducing fuel burn (TSFC)

• Nox can be reduced by clever design of the combustion chamber

• Contrails are affected by the conditions of the surrounding atmosphere and the emision of particles (soot). This could be reduced via a smart flight planing method or SAF

Limits are already in place for

• smoke

• nitrogen oxides (NOx)

• unburned hydrocarbons (UHC)

• carbon monoxide (CO)

  
  

  Noise Certification is based on three operating points

• Lateral

• Takeoff

• Approach

Co2:

• Quantity easy to estimate, as it is linearly dependent on fuel consumption

• Mode and strength of effect on climate well understood

Nitrogen oxides (NOx):

• Quantity strongly dependent on combustion

• Cooling effect due to decomposition of methane

• Warming effect due to generation of ozone (pre-dominant)

• High uncertainty in predicting their role in terms of climate impact

Contrails:

• Formation and persistence of contrails highly dependent on ambient conditions (e.g. water saturation of the atmosphere) exhaust emissions (e.g. particle numbers/sizes, temperature)

• High uncertainty in predicting their role in terms of climate impact

Program director

• Overall responsibility for the program

Chief engineer

• Coordination of multiple modules / system-related tasks

• Reports to program director

Module team leader

• Integration of all components

• Coordination of all module-relevant tasks

• Reports to chief engineer

Component team leader

• Coordination of all component-relevant tasks

• Reports to module team leader

European Emission Trading System EU-ETS:

• There a set (limited) number of allowances that can be traded if not needed. The amount decreases year over year and therefore the Co2 cost increase over time.

• This incentivises companies to emit less Co2 and invest in green operating methods.

• All flights within the EU + European Economic Area

• Domestic flights are also covered by the EU-ETS

ICAO Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA):

• International flights between CORSIA member countries

• Domestic flights are not covered

• Member states represent more than 75% of global air traffic

• Limitation on CO2 emissions

• Price is currently only $1/ton

Founded 1934

Today locations in North america, germany, poland. (And way more maintance outposts)

• Digitalization

• Open work space

• Short distances between disciplines

• Interactive exchange

• Virtual engine

• Digital twin

1. Target orientation

• Each member is aware of the team’s goals, tasks and responsibilities

• Each member is committed to achieving the milestones that lead to the completion of each task

2. Open communication

• Everyone’s opinion is heard, problems are discussed openly as they arise

• Everyone is committed to playing their part in working together to reach a consensus

3. Efficient, qualified team members

• Each member is fully trained and can speak on behalf of their functional area

• If not, they seek help and guidance from their supervisor

4. Committed participation

Fully installed engine (With outer nacelle drag)

Streamtube engine (Resistance on inner core cowl and nozzle plug, pylon Pre-inlet losses)

Installed engine (Power take-off, Customer bleed)

Uninstalled engine (Engine without take-offs)

Tech Radar

Prelimininary Design

Product Definition

Product Concept

Product Design

Verification & validation

Support

Potential product requirements and the technology radar -> lead concepts

Assessment of disruptive technologies

Promising lead concepts -> advanced product designs (APDs)

Design studies try to find the optimum compromise between competing objectives

After the preliminary design, only a relatively small proportion of costs have been incurred, but 95% of the costs have been defined

Materials developments must be identified and started much earlier than engine development

Safety requirements in aerospace significantly determine materials selected

>60% of parts are coated to protect them against wear and aggressive media, and to extend their service life

Comparative studies seek the optimal trade between conflicting goals

Trade factors make it possible to convert the conflicting target parameters into each other

Integrierte Produkt-

• Erfindung (Invention)

• Entwicklung (Development)

• Erstellung (Production)

• Erhaltung (Maintenance)

Developing a good product hinges on each phase considering the experience and requirements of the other phases

-> end-to-end mindset

Climate targets usually only limited the Co2 emissions

Paris climate agreement 2014 was a paradigm shift, since it limited climate warming.

-> Non Co2 effects which dominate the climate impact of aviation are included

Since the aviation industry needs quite some time to adjust and develop new planes, in the coming years/decades the relative share of aviations climate impact is going to grow!

Mission requirements (Find critical operating points, Takeoff, Top of Climb…):

- Cruise - optimum specific fuel consumption (SFC)

- Takeoff (MTOW) - maximum loads and temperatures

Operability:

- Surge marginmust be maintained at all operating points

Service life requirements:

- Service life requirements for the engine typically result from the

desired timing of maintenance intervals

Determining technological needs (Innovation management)

Drivers in aviation (pull factors)

• Global warming: Lower emissions, higher efficiency

• Profitability: Low costs, durable engines

• Society: Low costs, low noise, high level of safety

New technologies (push factors): Serve to enable new cycles,

improve efficiency, reduce weight, reduce emissions, increase reliability, etc.

1. Specific fuel consumption

The reduction in mission fuel consumption can be more than achieved through more efficient engines, since the aircraft gets lighter

2. Weight

Additional components add weight that increase the aircraft’s thrust requirements and thus its mission fuel consumption.

3. Nacelle drag

Nacelles are longer and as a result generate more drag (less damaging than additional width/diameter.)

4. Additional materials

Aircraft with WET engines carry, for instance, tanks with extra water for takeoff.

Wing:

• Center of gravity moves toward rear

• Lower wing bending moment due to increased weight

• Longer engine nacelle due to heat exchanger

• Higher wing position

HPC:

• Small core size

• High aspect ration blades

LPT:

• Low cax/u design

• Endwall contouring

Climate Impact:

• No reduction in contrails (Less soot with SAF -> less contrails)

• -25% Co2

• -53% Nox

Overall -20%, with SAF -63%

-> Fast and easy to accomplish reduction

Evolutionary -> Revolutionary

• GTF – 2nd generation

• WET – Water-enhanced turbofan

• FFC – Flying fuel cell

Static Full System Demonstrator (600 kW Propulsion System)

Dynamic Full System Demonstrator (600 kW Propulsion System) (FFC on a truck)

Static Multi-Mega-Watt System Demonstrator (>1000 kW Propulsion System)

MTU’s approach:

Thorough and holistic functional analysis of primary and secondary use cases showing the start and backbone of system development

The balance of plant describes the fuel cell’s auxiliary units, which are necessary for its stable operation

The FC air system supplies the fuel cell with conditioned oxygen from the ambient air for

• compression, humidification, temperature control, filtration

The FC H2 system supplies the fuel cell with conditioned hydrogen for

• modulation of H2 operating pressure

• recirculation of unused hydrogen (active/passive)

FC cooling system dissipates reaction heat

-> Leads to a parasitic load of 10–15%

- Very low contrail production

- 100% Co2

- 100% Nox

-> Almost climate neutral

Typically, an airframer defines an aircraft with potential engine variants

Requests for information (RFIs) are used to coordinate key parameters with the engine manufacturer

The actual down-select among different engine providers is initiated through a request for proposal (RFP)

Typically one or two engine providers qualify for engine selection -> program start for engine development -> typically accompanied by an agreement with an airline as launch customer

Combustion chamber

Steam in the primary zone reduces the flame temperature through high water heat capacity and lower oxygen concentration overall.

-> This allows the combustor to run at a higher equivalence ratio overall (richer) -> the engine’s specific power output increases

- Stable combustion under all operational conditions

Vaporizer

Recovery of exhaust gas heat through vaporizing water

- Integration (volume & weight)

- low pressure losses

Condenser

Condensation of water from exhaust gas

- Integration: volume & weight (with low pressure loss)

Separator

Best-known intellectual property right:

“The patent is officially issued and is limited to a defined territory for a specific period of time. The patent owner is

entitled to prohibit others from using the invention.”

They represent an opportunity and a risk at the same time

• Investments in R&D can be secured through patents

• The company must seek to avoid infringement on patents

Trade secrets:

Selected aspects of technological progress that arent disclosed through the publication of a patent

LH2 has 2.8 times the gravimetric energy density of kerosene, but 4 times the volume

Extraction as gas

Controlled heat input into tank ensures evaporation

Less space for cargo/passengers

Higher drag

Provide proof that specifications (thermodynamic process, etc.) can be met

Demonstrate that work can be completed on time, on budget and with the available test stand capacity

Identify risks as well as measures/plans for mitigation

Show that the draft concept and development plans are suitable for the upcoming design phase

Detailed design of components (technical drawings, tolerances, specifications, etc.)

Approval of components for production of early tests

Planning of the validation and approval program for engine, components and parts

Providing sufficient test results for definitive analyses & validation of the analytical models

Production approval for components

Proof that the test results and their evaluation show that specified values have been met

Demonstrating that safety and reliability requirements have been met

Proving that the desired design/hardware standards are suitable for the subsequent high volume production phase

Different market segments:

Airframers:

Defining a thrust class

SFC, weight, climate impact

Offtakes: Onboard electronics, hydraulics, bleed…

Defining the geometric dimensions of the engine by means of

installation constraints

- Maximum fan diameter

- Gully height: distance from wing

- …

Key stakeholders:

Airline (Mission fuel consumption,Direct operating cost (DOC),reliability)

Residents (Noise,Local air quality)

Passengers (Cabin noise, Oscillations)

Authorities (Certification , ETOPS)

MTU believes that fuel cells have the potential to enable climate-neutral flight across relevant market segments

(Short range)

• Fault-tolerant architecture

• No buffer battery required

• High gravimetric power density

• Low volumetric power density leads to a large LH2 tank and limited space for cargo/passengers

  
  

Most engines are developed by consortia made up of several companies

• Share the high development costs

• Share the technical risk

• Individual companies specialize in specific engine modules

• Political factors

Milestone PP2 is used to demonstrate the feasibility of the advanced product design as well as the required technologies

Gate G1 defines the program start

Innovation management and intellectual property management are key parts of the product invention process

MTU is a “Subsystem/module partner”

-> MTU is not a first level supplier but also doesnt design the whole engine. It delivers submodules HPC for example to P&W

Aircraft engine development, manufacturing and support in all thrust classes

Commercial business: 30% of aircraft fly with MTU technology on board

Specialities:

• HPC

• LPT

• TCF (Turbine center frame)

Development costs per engine program > USD 3 bn

Development time > 5 years

Payback period for dev. costs: approx. 20 years

Rising pressure to innovate

Shorter product lifecycles

Benefits of integrated collaboration:

• Risk & revenue sharing partnerships

• Pooling partners’ expertise

Each phase begins/ends with a design review (DR) and a gate

At G2, all product technologies must demonstrate their “technological maturity” (T5)

Due to the turnaround times for hardware, the product definition of a configuration needs to be released some 15 to 18 months ahead of the targeted test

Opportunities

• Reduction in development costs

• Access to a larger pool of experts

• Closer proximity to customers

• Clever use of the expanded timeframe that results from work spread over multiple time zones

Challenges

• More coordination required

• Cultural differences

• Political landscape

• Greater demands on infrastructure (connectivity and data exchange)

• Loss of proprietary know-how

MTU Aero Engines North America (AENA) -> Close to Pratt & Whitney

MTU Aero Engines Polska -> manufactures components, performs component repairs

Material challenges mainly rise up because of the increased water vapor. This causes excessive corrosion

Climate Impact:

• Contrail Reduction by particle separator

• -35% Co2

• -80% Nox

Overall impact: -80%

Margins:

Various margins are applied during the design (boundary conditions are articifially more challenging)

TSFC margins is subject to opposing requirements:

-> sufficiently large margins to accommodate development risks

-> minimal margins for an overall low and thus competitive and attractive specification value

Bookkeeping:

Overall engine performance results from efficiency bookkeeping from individual modules

The efficiency of the FETT test results should then meet the prediction

The design goal for an engine is described in terms of various metrics

-> The metrics for the engine as a whole are broken down into the individual modules

- Metric of weight: 900 lbs -> 1% TSFC or

- Metric of efficiency: 1% hLPT -> −1% TSFC

“Can be used to evaluate the relative severity of deviations from target values”

MTU designation Design Make Build Guide (DMBG)

• Binding rules for engine components and engines

• Acceptable deviations must be approved through a

  waiver process

Lessons Learned (LL):

• Documentation of findings (positive + negative)

• LL use is non-binding

PDP is the basis of project planning in IP4E teams

• ensures transparency in the process landscape

• supports employee onboarding

• promotes efficiency and quality in IP4E teams

• defines logical relations between tasks

• references additional norms (incl. DMBGs) and other information