Frame 7EA Combustor Liner

The Frame 7EA Combustor Liner is a key hot-section component used in heavy-duty industrial gas turbines. It forms the inner wall of the combustion chamber, where compressed air mixes with fuel and burns to generate high-temperature gases that drive the turbine.

This component is widely associated with the GE Frame 7EA Gas Turbine, a widely deployed heavy-duty gas turbine used in power generation facilities worldwide. Because of the extreme thermal and mechanical stresses in this environment, the combustor liner must be manufactured using high-temperature alloys and precision fabrication processes.

Advanced turbine component manufacturers such as HGTP provide precision manufacturing services for combustor liners and other gas turbine hot-section components used in power plants and industrial energy systems.

Function of the Combustor Liner

The combustor liner is installed inside the turbine combustion chamber and performs several critical functions.

Flame Containment

The liner forms the primary boundary of the combustion zone, safely containing the combustion flame and protecting the outer combustion casing.

Airflow Management

It helps distribute compressed air entering the combustor, ensuring proper fuel-air mixing and stable combustion.

Thermal Protection

The liner protects surrounding turbine structures from direct exposure to extremely high combustion temperatures.

Cooling Air Distribution

Cooling holes and air channels allow a thin layer of air to flow along the liner surface, creating a film-cooling effect that reduces metal temperature.

Materials Used

Combustor liners must withstand continuous operation at extremely high temperatures, often exceeding 1000°C. Therefore, specialized high-temperature materials are required.

Nickel-Based Superalloys

Typical alloys include:

• Inconel 625

• Inconel 718

• Hastelloy X

Advantages:

• excellent high-temperature strength

• superior oxidation resistance

• strong resistance to thermal fatigue

• long service life in combustion environments

Heat-Resistant Stainless Steel

In certain designs, heat-resistant stainless steels may also be used, such as:

• AISI 321 stainless steel

• AISI 347 stainless steel

These alloys provide good thermal stability and welding performance.

Manufacturing Process

Producing a Frame 7EA combustor liner requires a combination of forming, machining, and high-precision drilling technologies.

Sheet Metal Forming

The cylindrical body of the combustor liner is typically fabricated from high-temperature alloy sheets using:

• rolling

• deep drawing

• precision forming

These processes create the basic liner geometry required for combustion chambers.

Precision Welding

Multiple sections of the liner are joined using advanced welding technologies such as:

• TIG welding

• laser welding

• electron beam welding

These welding methods provide high-strength joints while minimizing distortion.

CNC Machining

Critical features are finished using CNC machining processes.

Typical machined features include:

• mounting flanges

• interface surfaces

• bolt holes

• alignment features

Multi-axis machining centers ensure tight tolerances and accurate alignment within the turbine combustion assembly.

Cooling Hole Drilling

Combustor liners include hundreds of precision cooling holes used to protect the liner from extreme heat.

Typical hole diameters:

0.5 mm – 2 mm

Manufacturing methods include:

• laser drilling

• EDM drilling

• high-precision mechanical drilling

These holes allow cooling air to form a protective air film along the liner surface.

Technical Specifications (Typical)

While exact specifications depend on turbine configuration, typical parameters for Frame 7EA combustor liners include:

Outer diameter
500 mm – 1000 mm

Wall thickness
2 mm – 6 mm

Operating temperature
900°C – 1200°C

Cooling hole diameter
0.5 mm – 2 mm

Critical tolerance
±0.02 mm – ±0.05 mm

Surface roughness
Ra 0.8 – 1.6 μm

Quality Inspection

Because combustor liners operate in critical turbine sections, strict quality inspection procedures are required.

Dimensional Inspection

Coordinate Measuring Machines (CMM) verify all critical dimensions and geometric tolerances.

Non-Destructive Testing (NDT)

Typical inspection methods include:

• dye penetrant inspection

• ultrasonic testing

• radiographic testing

These tests detect cracks, porosity, and welding defects.

Material Testing

Additional verification procedures include:

• chemical composition analysis

• hardness testing

• metallographic inspection

These tests ensure compliance with turbine component material standards.

Applications

The Frame 7EA combustor liner is widely used in industrial gas turbine power generation systems, including:

• combined-cycle power plants

• gas turbine power stations

• industrial energy systems

• turbine maintenance and overhaul (MRO)

These liners are essential for maintaining efficient combustion, protecting turbine structures, and ensuring reliable power generation.

Turbine Component Manufacturing

Manufacturers specializing in turbine hot-section components, such as HGTP, provide advanced manufacturing capabilities including:

• CNC machining of superalloys

• turbine combustor component fabrication

• precision cooling hole drilling

• turbine component repair and replacement parts

These capabilities support the global power generation industry with high-precision turbine components designed for long service life.