The main objectives of FIRST were to deliver a fuel spray atomisation prediction capability, which can represent the unsteadiness of the atomisation process, for gas turbine injectors and to deliver an improved soot / particulate modelling methodology for combustion Computational fluid dynamics (CFD).
Before the FIRST project there was very little information available to describe the properties of atomisation from Rolls-Royce aero engine rich and lean burn fuel injectors. Lefebvre correlations were typically used to estimate the fuel spray boundary conditions for CFD modelling of these injectors in combustor flows. This coarse method used for numerical modelling made accurate prediction of combustor flow fields, and consequently emissions, difficult. Actual measurements of the fuel particle sizes and velocities were required before further progress could be made in improving modelling techniques.
A new test facility was built in the combustion laboratories in Rolls-Royce Derby that was specifically designed to enable PDA measurements of fuel sprays from engine injectors. All of the PDA and flow visualisation measurements for this study were performed by SCITEK. Test geometries were designed and made that represented a single sector of an engine combustor so that the spray conditions were more closely representative of reality. Lean and rich burn fuel injectors were tested at a range of conditions relevant to their respective engine cycles and detailed measurements of droplet sizes and velocities were made at numerous locations. The work was extended to include sprays from alternative fuels as a comparison to a standard kerosene spray.
The measurements of the spray from the fuel injectors have now provided the boundary conditions required for CFD modelling of Rolls-Royce engine combustors and has described the progression of the atomisation process as the flow moves downstream away from the fuel injectors. This is vital information for the improvement of numerical models to predict engine reacting flows. The CFD models can now be validated against the spray measurements for a wide range of geometries and conditions and a step change in modelling accuracy will be the result. Future designs of aero engine combustors and fuel injectors will benefit from the improved modelling accuracy.
As part of our fluid mechanics activities we offer spray characterisation services which we carry out either at the customers site or within our own laboratory. This type of work is carried out using in-house instrumentation like the Malvern and Phase Doppler Particle sizing systems. Our Phase Doppler system is mounted on a 3D traversing system which allows for a fully automated mapping of sprays. We can also deal with mapping transient sprays such as those generated by medical inhalators. Laser light sheet is also another technique which we frequently use to obtain various spray characteristics like spray cone angle and density.
Areas of Expertise:
Inlet fog boost in industrial gas turbines
Performance studies of spray nozzles
Routine evaluation of Aerospace fuel nozzles
Fuel spray placement studies during ignition
Fuel spray studies in a cross flow for CFD validation
Expertise in All Major Laser Diagnostic Techniques
The experimental and computational fields of fluid dynamics are complimentary skills. SCITEK has a great deal of experience in both.
Flow visualisation and quantitative flow measurement techniques are used to see what is actually happening. The results can be used in research, to validate CFD models and to diagnose the problems that occur in real-world situations. Based on the application, we are able to choose the most suitable techniques and, if required, design or modify experimental rigs to get the best results.
Our experiences in the experimental field of fluid dynamics have led us to develop a number of seeding products for small to very large scale rigs and wind-tunnels and for very high temperature applications.
SCITEK can deliver turnkey solutions to your needs or provide a consultancy service for systems design. Solutions are tailored explicitly for the customers requirements and range from simple monitoring stations to full real-time, robust, reliable control systems for long term (thousands of hours) testing.
We have considerable experience in many different types of application ranging from laboratory scale research rigs to production facilities and provide support for installations that we have not previously been involved with.
Where possible we prefer to use COTS equipment, but as a result of particular project requirements, we have developed a number of standalone instruments that can be used out of the box, or can be tailored for individual customer needs.
We recommend National Instruments hardware and their software development platform LabVIEW™ where appropriate as the best solutions for rapidly developed and robust control systems based on our experience with a large number of competing platforms. We have extensive experience in the use of National Instruments’ products and in October 2004 National Instruments made us one of their Alliance Partners.
At the forefront of technological advance, we make a point of being actively involved in collaborative programmes between academia and industry in the development of new sensors, systems and methods.
Our installed systems base includes:
Solid Oxide Fuel Cell (SOFC) test facilities – Systems for unattended endurance testing (>3000 hours) of high temperature SOFCs with automated rig parameter profiling, IV curve control and logging. The system controls and monitors furnace temperature, rig pressure, gas mass flow, pressurised water delivery, cell temperatures, voltages and currents, provides alarm and event logging, and local and networked backup data logging.
Complete multi-site System Control And Data Acquisition (SCADA) system for rig control and acquisition data from full-scale combustion research rigs for a leading aerospace company.
Discontinuity Detection System with rig control for testing up to 160 connectors simultaneously on a vibration rig for aerospace connector quality evaluation.
Experimental fibre-optic sensor evaluation platform on SCITEK installed Gnome engine (see Engineering).
PC based ultrasound applications development platform.