civil aviation project clay- 2021

"plasma direct-drive"
commercial passenger propulsion systems

Research and development thrust areas:

1). Fan blades

- material science change

2). Compressor blades

- material science change

3). Turbine blades

- material science change

4). Combustor section

- laser ignition retrofit

- conversation to renewable fuels

5). Exhaust section

- material science change

Clayton Industries is focusing research and development programs on replacing the traditional alloys and matrix composites selected for current turbofan blade manufacturing.

CLAYTON INDUSTRIES AVIATION COMPONENTS DEVELOPMENT

General Electric has invested heavily in developing an additive manufacturing business unit. Within 18 months, the team was able to print half of the machine, reducing 900 separate components to just 16, including one segment that previously had different 300 parts. The printed parts were also 40 percent lighter and 60 percent cheaper. “To make these parts the ordinary way, you typically need 10 to 15 suppliers, and you must contend with close tolerances. The assembly requires assembly by means of traditional mechanical issues relating to nuts, bolts, interfaces, welds and braces,”

The turbofan for the LEAP design could operate more efficiently with less fuel burn. The engineering change would require an extensive redesign of the fuel nozzle. The fuel nozzles tips’ interior geometry was too complex. It had more than 20 parts that had to be welded and brazed together. It was almost impossible to make. General Electric attempted to cast the fuel nozzle eight times and failed every time. The team at General Electric can conclude that advancing the turbofan assemblies components could only be achieved by changing the material science and the manufacturing process controls.

GE’s engineers had already moved on to the next challenge. A different team decided to create a brand-new advanced turboprop engine, or ATP. Using additive manufacturing, they consolidated 855 components into just a dozen parts. The simpler design reduced weight, improved fuel burn by as much as 20 percent and achieved 10 percent more power. Using 3D printing for rapid prototyping, the team was also able to cut development time by a third. Last summer, Textron Aviation picked the engine to power its new plane.

CLAYTON INDUSTRIES

BUSINESS MODEL- DEFINED:

To develop a European based additive manufacturing business to produce legacy civil aviation parts. The business can be expanded over time to produce new components or complete assemblies for current airframes. The niche business would focus on the turbofan sector of the industry. This focus was the result of established network with NASA and General Electric seasoned material science and manufacturing veterans. With this network of specialized talent, Clayton Industries is proposing a join venture with Dart Aviation to enter the manufacturing sector in the civil aviation industry.

The proposed starting point is with the turbine blades which have been prone to suffer from cracks. Industry has experimented with numerous manufacturing techniques and material science applications to resolve this haunting issue. The problem continues to not be resolved.

CERAMIC MATRIX COMPOSITES - ATTRIBUTES

High temperature (2700 degrees Fahrenheit)

Mechanical strength

Ability to maintain material integrity even after significant mechanical damage

Material can be doped to be configured for several additional material characteristics including load shedding

Dissimilar metal, or alloys can be grafted into interfaces without chemical bonding

Near-net shaping (product requires minimum machining to achieve desired tolerances)

Elevated temperature creep

Stoichiometric Material – uniformity and high efficiency (perfect ordering of atoms in crystal structure)

Increase the operating temperature window to allow higher thermal efficiency

Reduced weight – ceramic material density is one-third that of today’s nickel-based alloys, enabling over 50 percent reduction in the turbine component weight

MANUFACTURING PROCESS CONTROLS:

The flexible manufacturing process does not require extensive investment in tooling and molds.

Sufficient use of materials compared starting block alloy milling 80 % removal of raw materials. Saves cost and machining time.

Part consolidation which reduces several components required for assembly compared to welding or bolting individual parts. This reduces the problems which stem from interfaces or joints.

Conformal cooling (miniature tunnels throughout part through optimization for flow characteristics, and heat transfer) Ideal for the manufacturing of the turbine components. The design ability to perfectly match cooling channels to mating surface of the cooling or heating circuit. Extremely complex compound curves can be achieved instead of cross drilling straight runs in material. Gas turbine aero engines employ the Brayton cycle in their operation. A critical parameter for high thermal efficiency is a high overall pressure ratio, which in turn drives high turbine flow-path temperatures. Turbine inlet flow path temperatures are generally higher than the thermal limits of the component materials. Therefore, air from the compressor cools the components by a combination of internal and external flow path cooling. However, minimizing the required cooling flow increases the overall efficiency of the cycle. Hence the need for developing and maturing advanced material technologies with improved high temperature.

capability, such as ceramic matrix composites (CMCs)

Manufacturing techniques provide rapid prototyping for engineering changes. The numerous changes during the transition phases from R&D to production can be streamlined and implemented at a reduced cost.

TURBOFAN BLADES

YEARS OF PRODUCTION MATERIAL SELECTED MANUFACTURER:

1971 to 1984 Super Alloys

(INCONEL 738) All Manufacturers

1984 to Present Super Alloys with Ceramic based Environmental Barrier Coating (EBC) All Manufacturers

2015 TO Present Silicon Carbide Composite

General Electric / Safran

737 Max airframes

Problems with the composite fan blades and shrouds:

• Unresolved solution to Cracks

ENVIRONMENTAL BARRIER COATINGS (EBC)

A temporary solution was the introduction of ceramic based environmental barrier coating (EBC) to extend the life of fan blades. The EBCs also provide reduced erosion rates to enhance durability and prolong component life. Current research applies to adding ceramic matrix composites (CMC), and environmental barrier coatings (EBC) to the turbofan components.

Environmentally Responsible Aviation (ERA) Project

The project selected different types of ceramic matrix composites (CMC) components:

 CMC combustor liner

 CMC high pressure turbine vane

 CMC exhaust nozzle

Advanced EBCs specifically tailored to the needs of the CMC combustor and vane are also being developed. The primary objectives are to address commercial manufacturability of the complex-shaped components and to evaluate their performance under simulated engine operating conditions.

The system level benefits of the ceramic matrix composites (CMC) combustor liner are a 40% reduction in cruise NOx and a 60% reduction in cooling air. The system level benefit for the CMC turbine vane is a 3-6% reduction in fuel burn. Conventional CMC exhaust nozzles for large commercial aircraft offer a 20+% reduction in component weight. CMC mixer nozzles for regional jets and business jets offer increased mixing efficiency through improved shape retention at operating temperatures. Reduced fuel burn is the result in both cases.

COMBUSTOR LINERS MANUFACTURED WITH CERAMIC MATRIX COMPOSITES (CMC):

As a combustor liner material produced from ceramic matrix composites are an enabling material that can help meet the NOx reduction goals of ERA. Current superalloys require high cooling air flows to keep them below their maximum allowable operating temperatures (up to about 80% of their melting temperature). CMC materials offer operating temperatures that are 200 degrees -300 degrees Fahrenheit higher than for superalloys. The higher temperature capability and less component cooling requirements allow for a wider combustor design space so that it can be run more efficiently. Less cooling flow to the component allows for more air to be put into the combustion process. The higher temperature and improved combustion efficiency decreases the emissions of CO and NOx. The use of EBCs will increase the temperature capability of the CMC by an additional 300 degrees Fahrenheit (for example, an increase from 2400oF to 2700 degrees Fahrenheit).

CONSIDERATIONS FOR FUTURE DESIGNS:

Silicon Carbide is not an oxide (oxygen compound) which is a allows the problem of oxidation on the fan blades. At high temperatures undergoes passive and active oxidation which leads to degradation.

Passive oxidation is responsible for both the formation of a silica layer on the top of the surface and for the active oxidation for the release of volatile oxides. The material is not able to withstand high mechanical properties as oxidation occurs, and dramatic failures can result when exposed to stress. Moreover, in the aerospace field, water and corrosive gases are released by the propulsion system. This, along with high temperatures, is expected to enhance the degradation of SiC materials. However, SiC materials need to operate properly for a defined range of temperatures and various gas compositions.

CLAYTON INDUSTRIES PROPOSED TRANSITION TO AN INNOVATIVE TURBOFAN REPLACEMENT,:

 Laser-based ignition circuits which would replace the turbofan ignitor circuits. High-temperature plasma may be used as an ignition source and as a flame stabilizer to ignite a fresh fuel mixture.

 The concept of a plasma nozzle presented a variety of configurations of plasma igniter and fuel nozzle, which provided a new approach for reducing electrode ablation and energy consumption of the igniter. It was found that jet plasma had great advantages over arc plasma in terms of the reaction time for combustion, the plasma volume, the energy and transient temperature change, especially in the case of lean combustion. Plasma jet ignition has been applied to various combustor models. In the conventional turbofan engine combustor model, compared with the conventional spark ignition technology, the plasma jet ignition technology can greatly broaden the ignition boundary and shorten the ignition delay time.

 Synthetic Fuel produced from waste feedstocks (Syngas). Syngas can be produced for a fraction of JET-A fuel. The problems associated with water contamination in the fuel and adding Prist (to keep the jet fuel from jelling in the winter months does not apply.

 Plasma engine configuration drastically increases fuel efficiency, thrust, and environmentally clean burning unlike traditional combustion engines. The concept of the plasma jet energy density and performed much research on the plasma assisted ignition mechanism and flame characteristics. It was pointed out that the plasma could significantly accelerate the chain reaction of fuel and change the chemical reaction pathway of conventional combustion ignition.