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为研究等离子体对超燃尾喷管性能的影响,在尾喷管入口的组分中添加一定量的O、H和OH自由基以模拟等离子体的化学效应。采用9组元19步反应的H_2/Air化学动力学模型、有限体积法隐式格式和RNG k-ε湍流模型对尾喷管中的化学非平衡流动进行了数值模拟。结果表明:对于飞行马赫数Ma_∞=11,飞行高度h=40 km,以H_2为燃料的超燃冲压发动机,其尾喷管流动的化学非平衡效应不可忽略;当综合添加的O、H和OH自由基质量分数分别为0.64%,0.15%和0.64%时,尾喷管的升力和推力分别提升3.63%、2.21%;综合添加的O、H和OH自由基质量分数越大,尾喷管性能的提升量也越大,且提升得越来越快;当单独添加O、H或OH自由基时,尾喷管性能的提升与自由基的添加量呈现较强的线性关系。等离子体的化学效应可以提高超燃尾喷管性能。
In order to study the effect of plasma on the performance of the nozzle, a certain amount of O, H and OH radicals were added to the components at the nozzle end to simulate the chemical effect of the plasma. The chemical non-equilibrium flow in the tail pipe was numerically simulated by the H 2 / Air chemical kinetic model of 9-component 19-step reaction, the finite volume implicit scheme and the RNG k-ε turbulence model. The results show that the chemical non-equilibrium effect of the nozzle flow can not be neglected for the H_ 2 fuel scramjet with Ma_∞ = 11 flight and flight altitude h = 40 km. When the combined O, H and OH radical mass fraction of 0.64%, 0.15% and 0.64% respectively, the lift and thrust of the nozzle increase by 3.63% and 2.21%, respectively. The greater the mass fraction of free radicals of O, H and OH is, The performance of the larger the amount of promotion, and to enhance faster and faster; when adding O, H or OH free radicals alone, the performance of tail pipe nozzle and free radical addition showed a strong linear relationship. Plasma chemical effects can improve the performance of the jet nozzle.