Brayton is more than a Contract Engineering Provider:
While we do pursue Engineering engagements, we have the unique capability of being able to support clients through the prototype AND pilot production phases of product development. We also frequently become equity partners with our clients by contribution of our platform intellectual property, reduced service rates and ongoing engineering and management support as these ventures grow. Our expanded prototype / pilot production facility is slated to be on line by late 2009 to further enhance these capabilities.
Gas Turbines and Related Disciplines:
Brayton specializes in designing high efficiency, low emission recuperated gas turbine engines. Past projects range in power widely.
In our specialized area, Brayton combines rigorous thermodynamic modeling with advancements in heat transfer, aerodynamics, and combustion sciences. The foundation of optimal gas turbine design starts with comprehensive cycle and system analysis. Brayton has developed internal codes to perform the integrated cycle analysis and the following computational modules.
- Design point simulations
- Simple gas turbine cycles
- Recuperated cycles
- Intercooled recuperated cycles
- Intercooler reheat cycles
- Part-load performance simulation
- Incorporating physical compressor and turbine maps
- Parametric representation of the recuperator and intercooler
- Combustion stability and CO emission over the operating envelope
- NOx emissions over the gas turbine operating envelope
- Turbine and compressor sizing and parametric performance analysis
A block diagram of Brayton’s suite of computation tools is shown below:
Some of our engineering capabilities are highlighted below:
Aerodynamics / CFD Modeling:
Brayton Energy utilizes computational fluid dynamics to provide insight into a variety of fluid flow problems, including turbines, compressors, volutes, ducting, heat exchangers and manifolds, and combustion systems. That said, our general corporate position on CFD is that it is not to be used as a quantitative analysis tool. At Brayton we strive to validate the performance of complex aerodynamic systems with well-planned experiments, backed by rigorous testing procedures. Brayton Energy utilizes ANSYS FLUENT and CFX software, as well as Concepts NREC software in our design strategy.
Brayton Energy maintains design codes for the analysis of radial and axial turbines. Our performance prediction codes are based on NASA codes. Full blade design and analysis is accomplished with TurbAero™.
Brayton Energy maintains design codes for the analysis of radial and axial compressors. Our performance prediction codes are based on NASA codes. Full blade design and analysis is accomplished with CompAero.
High Speed Alternators:
High speed permanent magnetic alternators are becoming increasingly common in small turbomachinery design. Working with alternator design specialists in the field, Brayton supports the development of the integrated system, performing rotor dynamic analysis, bearing analysis and finite element stress analysis to insure that the products are successfully integrated with the high speed turbomachinery.
Gas Turbine Combustors:
Somewhat paralleling the recuperator history, Brayton and our engineers have participated in innovative combustor development programs since the early 1980’s. The experience of our staff consultant and mentor, Roy Norster, dates back even further. Our team led the very successful NREC and Ingersoll-Rand combustor development programs, achieving NOx and CO levels below those of any commercial gas turbine or microturbine. Recent Brayton projects have focused on advances in gas turbine combustor durability and bio-fuels combustion in gas turbines. Past projects have involved traditional gas turbine combustors, advanced premix-lean burn gas turbine combustors, thermal reactors, and fiber burners.
Brayton maintains in-house capability to perform combustion testing with a wide range of fuels. Our facility maintains strict safety procedures and is subject to periodic inspection by our local fire safety officer and our insurance company.
Combustor Projects and Clients:
Some of our past and current projects are highlighted below
Recuperators and high temperature heat exchangers
Members of the Brayton Energy team have been working on gas turbines for over 25 years. Though our team has not been together that long, engineers on our staff participated in numerous regenerator and recuperator projects over the years. Our team specializes in the most challenging heat exchanger applications, associated with high temperatures (600 to 1000 C), pressures from 3 to 30 bar, and environments involving high thermal gradients and transients. This diversity and depth of understanding has contributed to our new advanced recuperator and high temp heat exchanger products. The following chart highlights some of the direct experiences by the Brayton engineering staff.
Brayton maintains and operates a range of recuperator testing and materials analysis equipment
- High temperature – high pressure recuperator creep furnace: This test equipment is designed to expose recuperators to static internal temperature and pressure. The microprocessor-controlled system’s operating limits are tabulated below. The “Hot box” is sized for sub-scale heat exchanger or cell testing, accepting a specimen of nominally 120 mm x 600mm x 900 mm. Brayton has successfully used this rig to validate the creep life of high temp heat exchangers, using the data to extrapolate life using a method analogous to the Larson-Miller methodology.
- Burst hydro-testing: Our facility is configured for destructive testing, operable to hydraulic pressures of 100 MPa (12,000 psi).
- Heat exchanger manifold design and test rig: Brayton aerodynamicists have developed methods for optimizing headers and manifold design. Typically a 2-D flow table is built for each heat exchange, employing similitude methods. Precise static pressure mass flow and temperature measurements are combined with flow visualization techniques to characterize the components. The data is correlated with system models, including CFD tools to develop and optimize the complex matrix of geometric options.
- Full-scale recuperator thermal testing and fatigue: Using our facility air compressor (500 CFM, 350 psig) and occasionally rented compressors to supplement flow, and facility gas-heaters, Brayton has characterized the performance of large high temp heat exchanger modules. Measuring the thermal effectiveness requires close attention to flow profile, in addition to very accurate flow and temperature measurements. Likewise, fatigue life testing and model validation requires an in-depth understanding of thermal stress, combined with micro-thermal analysis. Brayton engineers and technicians have developed these skills over a 25 year career.