Plasma-Fluid Energy Transfers in Plasma Assisted Ignition

A three-dimensional model of plasma-fluid coupling is developed, including the Navier-Stokes, the drift-diffusion, and the radiative transfer equations, to investigate the energy transfers between plasma and fluid in repetitive-pulsed discharge ignition. A modal decomposition of the energy transfer is performed to determine the contributions of plasma to the mechanical coupling and pressure losses during ignition. The detailed model is validated against experiments and compared against a well-known empirical approximation. The main findings are that the modal coupling is dependent on the geometry of the electrodes and flat electrodes provide the strongest mechanical transfer into the acoustic modes. Uniform flow conditions decrease the extent of the mechanical coupling due to the decreased pressure velocity correlations in shear flows. Water vapor production reduces the entropic mode of the energy coupling.

本研究构建了一套等离子体-流体耦合（plasma-fluid coupling）三维模型，纳入纳维-斯托克斯（Navier-Stokes）方程、漂移扩散（drift-diffusion）方程以及辐射传输（radiative transfer）方程，用于探究重复脉冲放电点火过程中等离子体与流体间的能量传递机制。研究通过对能量传递过程开展模态分解，以明确点火阶段等离子体对机械耦合与压力损失的贡献程度。该精细模型通过实验数据进行验证，并与经典经验近似模型展开对比分析。主要研究结论如下：模态耦合与电极几何结构密切相关，平面电极可实现最强的声学模式机械能量传递；均匀流场条件下，由于剪切流中压力与速度的相关性降低，机械耦合的作用范围会随之缩小；水蒸气生成会削弱能量耦合的熵模式。