Numerical analysis of combustion of a hydrogen–air mixture in the model combustor of perspective ramjets during activation of molecules with O$_2$ resonant laser radiation

This paper presents a numerical study of the combustion of a hydrogen–air mixture in a model ramjet combustor with separate hydrogen and air supply during activation of O$_2$ molecules with resonance laser radiation at a wavelength of 762.3 nm and 193.3 nm. The calculation is made using the parabolic Navier–Stokes equations taking into account chemical transformations, laser irradiation, and the unevenness of the air parameters at the combustor inlet due to the complex gas-dynamic structure of the flow in the air intake. It is shown that the combustion efficiency at the combustor outlet can be increased a factor of 2.8 by redistributing the hydrogen supply through the system of fuel tank pylons. Further increase in the combustion efficiency can be achieved by exposure of a narrow flow region to resonant laser radiation, more effectively at a wavelength of 193.3 nm. The combination of laser exposure together with the hydrogen supply redistribution increases the combustion efficiency by a factor of more than 4.7 compared to the base case. Furthermore, this provides a 95% increase in the axial force component in the inner portion of the engine flow path, which provides a positive contribution to the thrust. Estimation of the energy efficiency due to the use of laser radiation shows that the laser energy input required to achieve this effect is 40–80 times (depending on the fuel supply method) less than the increase in the chemical energy (compared to the case of no laser exposure) released due to fuel combustion.