Simulation of supercritical fuel injection with condensation
Simulation of supercritical fuel injection with condensation
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DOI：
10.1016/j.ijheatmasstransfer.2014.08.081
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发表时间：
2014-12
影响因子：
5.2
通讯作者：
L. Qiu;R. Reitz
中科院分区：
文献类型：
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作者：
L. Qiu;R. Reitz
采用一个符合实际的状态方程模型，对超临界喷射和伴随的潜在冷凝过程进行了数值模拟。与现有的实验数据相比，在预测的注入剂密度与真实的气体模拟上看到了定性和定量的改进，强调了在超临界条件下热力学性质非理想性的重要性。最近开发的相稳定性和平衡求解器，利用基本热力学原理也适用于捕捉相变。据我们所知，这是第一个全面的模拟与实验数据的超临界注射与相分离。此外，模拟结果与实验结果一致的相变相关的三个方面。第一个观察结果是，预计发生冷凝，当且仅当注入剂和周围环境之间的温差足够大，以促进强烈的传热相互作用。模拟还表明，冷凝变得加剧时，室温度进一步降低。第二，这种冷凝仅可能用于超临界到亚临界注入，而不可能用于超临界到超临界注入。第三，冷凝液相被发现形成在射流边界处的“热”注入剂和“冷”周围气体之间的能量和混合相互作用是强的。强烈的局部热交换最终将混合物通过跨越露点线并冷凝而送入两相区。
Supercritical injection and the accompanying potential condensation processes were numerically investigated with a consistent treatment for both the fluid dynamics and thermodynamics with a realistic equation of state model. Qualitative and quantitative improvement was seen on the predicted injectant density with real gas simulations when compared to available experimental data, emphasizing the importance of thermodynamic property non-ideality at supercritical conditions. Recently developed phase stability and equilibrium solvers utilizing fundamental thermodynamics principles were also applied to capture phase transitions. To our knowledge, this is the first comprehensive simulation against experimental data of supercritical injection with phase separation. Furthermore, the simulation results were found to agree with the experimental results in three aspects related to the phase change. The first observation is that condensation is predicted to occur if and only if the temperature difference between the injectant and ambient is large enough to promote strong heat transfer interactions. The simulations also show that condensation becomes intensified when the chamber temperature is further reduced. Second, such condensation is only possible for supercritical-to-subcritical but not for supercritical-to-supercritical injections. Third, a condensed liquid phase is found to form at the jet boundary where the energy and mixing interactions between the “hot” injectant and the “cold” surrounding gas are strong. The intensive local heat exchange finally sends the mixture into the two-phase region by crossing the dew point line with condensation.