Characterisation of the eddy dissipation model for the analysis of hydrogen-fuelled scramjets

Abstract

The eddy dissipation model (EDM) is analysed with respect to the ability to address the turbulence–combustion interaction process inside hydrogen-fuelled scramjet engines designed to operate at high Mach numbers (≈7–12). The aim is to identify the most appropriate strategy for the use of the model and the calibration of the modelling constants for future design purposes. To this end, three hydrogen-fuelled experimental scramjet configurations with different fuel injection approaches are studied numerically. The first case consists of parallel fuel injection and it is shown that relying on estimates of ignition delay from a 1D kinetics program can greatly improve the effectiveness of the EDM. This was achieved through a proposed zonal approach. The second case considers fuel injection behind a strut. Here the EDM predicts two reacting layers along the domain which is in agreement with experimental temperature profiles close to the point of injection but not the case any more at the downstream end of the test section. The first two scramjet test cases demonstrated that the kinetic limit, which can be applied to the EDM, does not improve the predictions in comparison to experimental data. The last case considered a transverse injection of hydrogen and the EDM approach provided overall good agreement with experimental pressure traces except in the vicinity of the injection location. The EDM appears to be a suitable tool for scramjet combustor analysis incorporating different fuel injection mechanisms with hydrogen. More specifically, the considered test cases demonstrate that the model provides reasonable predictions of pressure, velocity, temperature and composition.

Simulation Study of Gas Explosion Propagation Law in Coal Mining Face With Different Ventilation Modes

“…The eddy current dissipation model, whose reaction rate is controlled by turbulent mixing, is used for nonpremixed flames. In combination with literature (Hassan et al, 2010;Halouane and Dehbi, 2017;Hoste et al, 2019;Chen et al, 2020;Tian, 2020), the ED eddy dissipation model, which is applied to the LES turbulence model is adopted for combustion model, and the simple algorithm is used for iterative solution with an iterative time step of 0.0005 s. The reliability of the turbulence and combustion model is verified below.…”

A Preliminary Investigation of a Hydrogen Injection Wedge Strut for a Scramject Combustor Application

“…The constants A edm and B edm describe the ease of eddy dissipation on a molecular scale, and the mixing of fuel and oxidizer eddies on a dimensional scale. An increase in A edm promotes molecular mixing of species, while an increase in B edm encourages reaction between the fuel and oxidizer in the presence of hot products [32]. The default settings of these constants are used, as this investigation serves to provide insight on how combustion effects the flow field, rather than an in-depth analysis on refining combustion models.…”

Further Development of Eddy Dissipation Model for Turbulent Non-Premixed Combustion Simulation

“…The EDM model has been investigated for its applicability to scramjet design by simulating three hydrogen-fueled scramjet configurations. The study highlights the importance of case-specific calibration, which can yield reasonably accurate predictions while reducing computational costs [6,7]. In Gobbatto et al [8], the EDM model is used in the numerical simulation of a hydrogen-fueled gas turbine combustor.…”