**7. Conclusion**

**6. Effect of H2 addition on the dynamic field and temperature**

*Numerical and Experimental Studies on Combustion Engines and Vehicles*

*Radial profiles of temperature at different positions from the burner.*

**Figure 9** shows the longitudinal velocity field for different percentages of hydrogen. By comparing the four fields, the potential cone for three configurations with the addition of hydrogen percentages (*α<sup>H</sup>*<sup>2</sup> ¼ 20%, 40% *and* 60%Þ are smaller than with pure methane. This indicates that the increase in velocity of the jet when adding hydrogen to the fuel reduces the size of the potential cone allowing the reactants to interact more effectively with oxygen and the ambient fluid. Note also that the addition of hydrogen reduces the height of the mixing area and consequently the flame height due to the high molecular diffusivity and low density of hydrogen promoting interaction between the jets more rapidly and the flow

**Figure 10** illustrates the radial temperature profiles for multiple hydrogen percentages in the fuel mixture. This figure shows that the substitution of a fraction of

**6.1 Longitudinal velocity field**

**Figure 8.**

**26**

features to the behavior of a single jet.

**6.2 Radial profiles of temperature**

In this chapter, a new combustion technique in a burner with three separated jets is used. The idea of this burner consists of separating combustible and oxidant to dilute the reactants with combustion products before the mixing of the reactants. This type of burner has a great interest for the industry and the sizing of these burners requires a good understanding of the mechanisms controlling the stabilization of the flame, the release of heat and the production of pollutants.

The Particle Image Velocimetry PIV is the technique used in experimental study in non-reacting flow and reacting flow inside the combustion chamber. The Reynolds Average Navier-Stokes (RANS) method is used in this numerical simulation

with Realizable k-ε as a turbulence closure model. The eddy dissipation model is applied to take into account the turbulence-reaction interactions.

The passive control added to the basic of the burner is based on the inclined of side oxygen jets towards the central natural gas jet in burner with three separated jets. From ϴ = 0° to inclined state ϴ = 30°, the jets fusion point becomes closer the burner as well as the dynamic field changes. The result shows that the inclination of the jets affects significantly the flow field and consequently the flame behaviour.

The effect of equivalence ratio and hydrogen on characteristics of a nonpremixed oxy-methane flame from a burner with separated jets is studied in this document. The velocity fields with different equivalence ratio (0.7, 0.8 and 1) are presented. Near the burner a decrease in the equivalence ratio increases the injection velocity of the lateral jet and keeps a constant velocity in the central jet. For the turbulence intensity, near and far from the burner, an increase in the turbulence intensity is observed in the two layers of internal mixtures, this makes it possible to improve the mixing and increase the stability of the flame. Thus, there is an increase in the adiabatic temperature of the flame, which promotes heat transfer and improves thermal efficiency.

The use of hydrogen solves instability problems of the flame that are related to lean combustion, due to the high diffusivity and reactivity of hydrogen in combustion. The results showed that the addition of hydrogen increased the flame velocity and the temperature while reducing CO2 and CO emissions due to the reduction of the carbon in the fuel.

**Author details**

Orléans, France

France

**29**

and Jean-Charles Sautet<sup>4</sup>

University, Abha, Saudi Arabia

Mohamed Ali Mergheni1,2\*, Mohamed Mahdi Belhajbrahim2

*A New Combustion Method in a Burner with Three Separate Jets*

*DOI: http://dx.doi.org/10.5772/intechopen.90571*

\*Address all correspondence to: mmerghni@kku.edu.sa

provided the original work is properly cited.

1 Department of Mechanical Engineering, College of Engineering, King Khalid

3 ICARE-CNRS, Avenue de la Recherche Scientifique, University of Orléans,

4 CORIA, CNRS-Université et INSA de Rouen, Saint Etienne du Rouvray, Rouen,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

2 College of Engineering, University of Monastir, Monastir, Tunisia

, Toufik Boushaki<sup>3</sup>

### **Nomenclature**


*A New Combustion Method in a Burner with Three Separate Jets DOI: http://dx.doi.org/10.5772/intechopen.90571*
