Session: 05-05: Combustion Measurements 2

Submission Number: 174642

Spatially Resolved Emission Measurements on a Hydrogen-Fueled Full-Ring Combustion Chamber Test Bench 

Since hydrogen eliminates direct carbon emissions, it is widely regarded as a promising fuel to reduce greenhouse gas emissions. However, hydrogen combustion introduces new challenges, particularly related to pollutant formation, which necessitate precise and dynamic monitoring, especially under transient operating conditions. In this context, a detailed understanding of the exhaust gas composition is essential, as it provides valuable insights into the mechanism of pollutant formation and serves as a key indicator of combustion efficiency, stability and overall system performance.

This work presents a tunable diode laser absorption spectroscopy (TDLAS)-based measurement system adapted for extractive exhaust gas analysis in a full annular combustor rig. The system enables high-temporal-resolution detection of the key combustion species NO, NO₂, O₂, and H₂O. While these species are traditionally measured using different sensing principles, such as chemiluminescence for NO and NO₂ and paramagnetic detection for O₂, the application of TDLAS to all four simultaneously represents a significant advancement. It allows the use of a single diagnostic platform for comprehensive exhaust gas analysis, combining calibration-free operation, independence from mass flow and gas matrix variations, and excellent temporal resolution.

For spatially resolved diagnostics, the measurement probe was traversed once per operating point around the annular exit plane of the combustion chamber in a predefined time (6 min or 12 min). The continuous acquisition of data at a frequency of 2 Hz and the subsequent time-to-angle transformation enabled reconstruction of angular emission profiles with a spatial resolution of 0.5° or 0.25°, respectively. This enables the determination of the exhaust gas concentrations emitted by each individual injector within the combustion chamber.

A comparison with conventional measurement equipment under stable combustion conditions demonstrates that the TDLAS system not only reproduces results from established techniques but can even surpass them in terms of temporal resolution and sensitivity. These results underline the suitability of TDLAS as a versatile diagnostic tool for exhaust gas analysis in gas turbine combustion. The capability to simultaneously measure NO, NO₂, O₂, and H₂O with a single sensor system offers new opportunities for comprehensive multi-species diagnostics.

Presenting Author: Leon Schuhmann TU Darmstadt FG Reactive Flows and Diagnostics

Presenting Author Biography: I am a third-year PhD student at the Institute for Reactive Flows and Diagnostics, Technical University of Darmstadt, under the supervision of Professor A. Dreizler. Our group focuses on laser diagnostics for reactive flows and the development of advanced measurement techniques. My research centers on tunable diode laser absorption spectroscopy (TDLAS) for precise exhaust gas and temperature measurements in the high-pressure, high-temperature environment of gas turbine combustion chambers. To improve measurement sensitivity, I am exploring the use of multipass cells to extend the optical path length and enhance detection limits.

Authors:

Leon Schuhmann TU Darmstadt FG Reactive Flows and Diagnostics
Matthias Bonarens TU Darmstadt FG Reactive Flows and Diagnostics
André Fischer Rolls-Royce Deutschland Ltd & Co KG
Max Staufer Rolls-Royce Deutschland Ltd & Co KG
Andreas Dreizler TU Darmstadt FG Reactive Flows and Diagnostics
Steven Wagner TU Darmstadt FG Reactive Flows and Diagnostics