Objectives

OBJECTIVE 1

Understand and characterise the effect of pressure on the turbulent burning rate of H2 premixed flames

InsigH2t will quantify the pressure dependence on the coupling between chemical reactivity, molecular diffusion and turbulence on the burning rate of H2-air premixed flames through a systematic series of experiments and numerical simulations. A focus on canonical flame configurations will ensure scientific generality. The flame configurations to be used are propagation-stabilised jet flames, propagation-stabilised swirl flames and autoignition-stabilised flames over a backward facing step.

  • An experimental database of turbulent burning rate and emissions measurements for canonical premixed H2-air flames and selected blends of H2/CH4-air (H2>80% vol), at elevated pressure conditions
  • A numerical database from direct numerical simulation (DNS) calculations of premixed H2-air flames in canonical configurations providing first-principles (model-free) estimates of the turbulent burning rate at elevated pressure conditions.
  • A physical understanding of the effect of pressure on the turbulent burning rate and an accurate scaling law extracted from the experimental and DNS results.
  • An upgraded/novel turbulence-chemistry interaction (TCI) model based on the pressure scaling law implemented high-fidelity (high-resolution) large eddy simulations (LES).
  • An improved understanding of the effect of pressure on the mechanism of global stabilisation, flashback and blowout of turbulent premixed H2-air flames in canonical configurations.
  • A numerical database from high-fidelity/high-resolution LES calculation performed using the upgraded/novel TCI model and validated against premixed H2-air flames in canonical configurations at elevated pressure conditions.

OBJECTIVE 2

Understand and characterise the pressure dependence of the thermoacoustic response of H2 premixed flames

The second objective of InsigH2t will quantify the effect of pressure on the thermoacoustic response of canonical (propagating) flames through a series of experiments, numerical simulations, and physics-based modelling. Experiments will characterise the effect of operating pressure on the dynamic response of acoustically forced flames by tracking the flame dynamics with OH* chemiluminescence and measuring flame transfer matrices (FTMs) using the multiple microphone method (MMM), from which the flame transfer function (FTF) can be inferred. Forced LES with the new/upgraded TCI models will be used to extract FTFs and validate against the experiments. This will lead to new/upgraded physics-informed low-order models able to accurately predict the impact of single physical mechanisms and pressure scaling of the thermoacoustic system response enabling the design and development of countermeasures.

  • An experimental database of FTMs/FTFs and emissions at elevated pressure for a range of operating conditions of canonical premixed H2-air flames and selected blends of CH4/ H2-air (H2>80% vol).
  • Implementation and validation of pressure dependent FTFs into low-order models to predict the thermoacoustic response of combustion systems featuring canonical premixed H2-air flames.
  • Validate numerically derived FTFs from high-fidelity LES of forced canonical premixed H2-air flames at two pressure levels.
  • Development physics-informed flame models allowing insight into the effect of different physical mechanisms and pressure on the flame response.
  • Derivation of passive strategies for controlling the combustion dynamics of systems operating with different fuel mixtures and at different load conditions.

OBJECTIVE 3

Validate simulation methods of advanced fuel injector concepts and demonstrate the ability to operate cleanly and efficiently with 100% H2 at relevant pressure conditions.

Objective 3 will demonstrate enhanced modelling and design capability for industry. This will start with the adaptation of the detailed sub-grid scale models for TDI/TCI into the industrial-LES context validated against experimental data and high-fidelity LES of the canonical flames. The enhanced prediction capabilities of the industrial LES will be tested on realistic geometries. Experimental data at relevant GT operating conditions will be used to verify the enhanced modelling capability in the prediction of the combustor performance in terms of pollutant emissions, thermoacoustic stability maps, and fuel flexibility of different burner configurations. This verification will pave the way for the design of new fuel injection concepts aimed at the optimization of the hardware performance.

  • Integration of the new sub-grid scale models into commercial CFD codes for the proper modelling of TDI/TCI effects at elevated operating pressures of industrial hardware.
  • Extension of the methodology to technically premixed configurations relevant to industrial geometries.
  • A set of industrial LES of a selected industrial hardware operating at atmospheric pressure with increasing hydrogen content up to 100% H2 for validation of the extended methodology and comparison with the corresponding experimental test data.
  • A set of industrial LES operating at relevant GT conditions able to provide an improved understanding of the operating pressure rise impact onto the burners performance in two different combustor architectures, single stage, and sequential combustion systems. Optimized burner designs conceived through the employment of the extended methodology and able to reduce the emission and extend the stability window of the combustion system.