基于支板燃烧室的喷管化学非平衡效应

采用有限体积法全隐式格式和代用燃料C₁₂H₂₃的10组元13步化学反应Arrhenius有限速率模型研究煤油燃料超燃冲压发动机单边膨胀喷管(SERN, Single Expansion Ramp Nozzle)内的化学非平衡流动,通过建立支板燃烧室——喷管模型有效解决了单边膨胀喷管模型的"入口薄层"问题.计算结果表明,整个单边膨胀喷管内,流动呈现化学非平衡效应,喷管入口附近区域尤其显著;非平衡流动喷管性能明显高于冻结流动,随发动机当量混合比 ε增加,非平衡流动的喷管推力系数和升力系数相对冻结流动的百分比增量 δ不断升高,当 ε=0.8时,推力系数百分比增量 δ_CF达到9.41%,升力系数百分比增量 δ_CY达到16.39%,化学非平衡效应对煤油燃料超燃冲压发动机尾喷管性能的影响不可忽略.

Nozzle chemical non-equilibrium effects based on strut combustor

The finite volume method in implicit scheme and surrogate fuel C₁₂H₂₃'s 10 species and 13 step reactions Arrhenius finite-rate model were adopted to investigate the non-equilibrium chemical reaction flow in kerosene-fueled scramjet single expansion ramp nozzle (SERN), and the ‘inlet thin layer' problem in SERN model was effectually solved by establishing the strut combustor-SERN model. Numerical simulation results show that the chemical non-equilibrium effect exits in the whole SERN, especially near the nozzle inlet zone; The SERN performance with non-equilibrium chemical reaction flow is obviously higher than that with frozen flow. With the increase of engine equivalent mixture ratio (ε) the δ grows up, which is the percentage of increment about nozzle thrust coefficient and lift coefficient with non-equilibrium chemical reaction flow relative to frozen flow.When the ε=0.8, thrust coefficient increment δ_CF=9.41%, lift coefficient increment δ_CY=16.39%, thus the chemical non-equilibrium effect of kerosene-fueled scramjet nozzle cannot be ignored.