Numerical analysis of combustion of a hydrogen-air mixture in an advanced ramjet combustor model during activation of O-2 molecules by resonant laser radiation

摘要

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 by resonant laser radiation at a wavelength of 762.3 nm and 193.3 nm. The calculation is made using the parabolized Navier-Stokes equations taking into account chemical reactions, laser irradiation, and the nonuniformity of 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 completeness at the combustor outlet can be increased by a factor of 2.8 by redistributing the hydrogen supply through the system of fuel tank pylons. Further increase in the combustion completeness can be obtained 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 with hydrogen supply redistribution increases the combustion efficiency by a factor of more than 4.7 compared to the base case. In this case, this provides a 95% increase the longitudinal force component in the portion of the internal engine duct that provides a positive contribution to the thrust. Estimation of the energy efficiency of using 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.