Applications

Aero turbines (Embedded Flight Sensors)

The development of practical, reliable TDLAS instrumentation opens new opportunities for measuring gas temperature and pressure inside turbine engines, particularly in the harshest zones of the engine at stations 4-8. Zolo Technologies works with engine developers to provide flight-qualified instrumentation for such applications.
Zolo Technologies has developed several key enabling technologies for embedded flight sensing:

Alignment-insensitive, single-ended optical probe.
Rather than separate transmit and receive optics whose alignment must be carefully maintained, the single-ended probe functions by scattering transmitted laser light off of a surface inside the engine, such as a metal or TBC-coated part. The same probe collects the backscattered light and routes this signal back to a photodetector. Because the probe collects scattered light off of rough surfaces rather than reflected light off of mirror-like surfaces, the measurement is almost completely insensitive to optical alignment.

T-4 compatible optical probe. The single-ended optical probe is designed to withstand the temperatures, pressures, and vibrations expected in the engine combustion zone.
High-performance TDLAS electronics. Developed for Air Force scramjet applications, this flight-ready electronics package is essentially an entire TDLAS system in a package the size of a cigar box. The electronics module includes high sensitivity receiver circuitry capable of collecting and digitizing signals.

Engine inlet and compressor diagnostics
In addition to gas measurements at or aft of the combustion zone, our TDLAS instruments can provide diagnostic information, such as ambient air temperature and pressure, humidity, and liquid water content at the engine inlet. Additionally, Zolo Technologies has a toolbox of capabilities that allow measurement of gas dynamics in the compressor, allowing engine developers to validate computational fluid dynamics models and optimize compressor performance.

Turbine ground test
Using optical probes designed for embedded flight sensors along with wavelength-multiplexed TDLAS instruments for industrial applications, Zolo Technologies can deliver diagnostic and test instrumentation for engine developers and diagnosticians. Zolo Technologies’ patented wavelength multiplexers allow the simultaneous measurement of multiple gas species along a single measurement path. Additionally, Zolo Technologies has significant experience using optical tomography to reconstruct planar, 2-D temperature and gas concentration profiles. Zolo Technologies measured temperature distributions behind a J60 turbojet to demonstrate the viability of this approach.

Engine maintenance
Imagine being able to diagnose turbine engine problems, such as malfunctioning combustors, hot streaks, turbine problems, or screech onset, non-intrusively and without having to remove the engine from the aircraft. Zolo Technologies’ tomographic ground test instrumentation can help make that scenario a reality. Think of it as a CT scanner for jet engines. By mapping out exhaust gas profiles directly behind the engine nozzle – in both space and in time – external diagnoses are possible and offer potential time and cost savings to engine maintenance shops. Zolo Technologies measured single-path engine exhaust properties at measurement rates where acoustic modes in the combustion dynamics are evident.

Combustion turbines
The same technologies developed for aero turbines – single-ended optical probes, high-performance TDLAS electronics, signal processing algorithms for high-temperature/high-pressure environments – are applicable to combustion turbines. Would you like to know more about the spatial distribution of gas temperatures in your turbine?

Combustor and augmentor testing
Combustion instabilities are a big problem for augmentor developers. Screech and rumble can tear apart an engine in a hurry. The combustion dynamics involved in these processes are difficult to model, and the models that are available need validation through measurement. We are currently working with augmentor developers to address the need to measure flame dynamics with very high spatial and temporal resolution. We have previously measured high frequency turbulence fluctuations in augmentor flames.

Hypersonic engine diagnostics
Air Force hypersonics research funded much of Zolo Technologies’ TDLAS electronics development. Under those R&D efforts, we developed methods of measuring gas concentrations, temperatures, and even flow velocities in hypersonic flows.

Combustion research
Combustion dynamics researchers need to know – with very high spatial and temporal resolution – where combustion is happening. Zolo Technologies has the know-how to make these measurements real by combining already-developed high speed electronics for high temporal resolution with optical tomography for high spatial resolution.

Engine and aircraft icing detection
Zolo Technologies is currently developing an embedded flight sensor for detection of aircraft icing onset. Using the same TDLAS measurement principles that we usually apply at flame temperatures, we measure much colder air to detect when atmospheric conditions are right for icing formation and when ice formation actually occurs.

Zolo Technologies, Inc.