Abatement of NOx emissions from pulse detonation combustion

• Applicant: Professorin Dr.-Ing. Neda Djordjevic
• Subject Area: Fluid Mechanics ; Energy Process Engineering
• Term: from 2016 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 317741329

• Final Report Year: 2025

Final Report Abstract

Detonation-based Pressure Gain Combustion (PGC) increases efficiency by altering the thermodynamic cycle of combustion. It can therefore play a decisive role in the development of future combustion concepts. However, managing gaseous pollutant emissions due to the occurring high temperatures and pressures in detonations remains an open research question. This research project aimed to improve the understanding of the influence of operating conditions on the formation of gaseous pollutants in a multi-cycle Pulse Detonation Combustor (PDC). To this end, experimental and numerical studies were conducted, and potential strategies to mitigate these emissions were discussed. A measurement framework for analyzing gas samples from the transient exhaust of a PDC was established, and simplified numerical models were introduced. Special attention was given to ensuring that measurements and numerical results are representative of cycle-averaged emissions and remain comparable under different operating conditions. The comparison of experimental and numerical results highlighted the crucial role of modeling heat losses. When these were accounted for, the models produced accurate predictions for NOx and CO concentrations in H2 and C2H4 detonations, which can reach up to several thousand ppm. Thermal NO is the primary formation path due to high temperatures. CO emissions are controlled by equilibrium concentrations, influenced by heat losses and product gas temperatures. Conventional dilution-based primary pollutant reduction methods decrease detonability and can lead to the failure of detonation initiation at high dilution rates. Here, the detonation cell size λ has proven to be a useful universal parameter for quantifying detonation capability, regardless of the choice of fuel or initial conditions. Using the test bench-specific limit value for λ, it was shown that only when applying precompression are lean mixtures and Exhaust Gas Recirculation (EGR) as the most promising strategies able to provide theoretical NOx reduction rates of up to 98 %. The data and methods generated during the course of this research project provide a foundation and a framework to support future research, enabling PGC to become a low-emission technology.

Publications

• Experimental and low-dimensional numerical study on the application of conventional NOx reduction methods in pulse detonation combustion. Combustion and Flame, 233, 111593.
  Garan, Niclas & Djordjevic, Neda
  
• Unsteady Effects on NOx Measurements in Pulse Detonation Combustion. Flow, Turbulence and Combustion, 107(3), 781-809.
  Hanraths, Niclas; Bohon, Myles D.; Paschereit, Christian Oliver & Djordjevic, Neda
  
• “Detonationszellengröße als möglicher Auslegungsparameter für emissionsarme Pulsdetonationsverbrennung”. In: 30. Deutscher Flammentag. Garbsen: Deutschen Sektion des Combustion Institutes und Deutsche Vereinigung fur Verbrennungsforschung, Sep. 2021.
  N. Garan & N. Djordjevic
  
• “Stratified fuel injection as a measure for NOx mitigation in pulse detonation combustion”. In: European Combustion Meeting. 2021.
  N. Garan, F. Habicht, C. O. Paschereit & N. Djordjevic
  
• Consistent emission correction factors applicable to novel energy carriers and conversion concepts. Fuel, 341, 127658.
  Garan, Niclas; Dybe, Simeon; Paschereit, Christian Oliver & Djordjevic, Neda
  
• “Applicability of a low-resolution URANS Simulation for Deflagration to Detonation Transition Prediction in a Pulse Detonation Combustor”. In: Proceedings of the 11th European Combustion Meeting. 2023.
  A. Mohammadkhani & N. Garan
  
• “Gaseous Pollutant Emissions from Pulse Detonation Combustion”. Diss. Technische Universitat Berlin, 2024.
  N. Garan