论文标题
可变形液燃料液滴的准稳态蒸发
Quasi-steady evaporation of deformable liquid fuel droplets
论文作者
论文摘要
这项工作涵盖了在对流流条件下液滴变形对其蒸发率的影响。通过将Weber号码（$ WE $）从$ 1-12美元和雷诺（Reynolds）的数字（$ re $）从$ 25 $到$ 120 $减少到高压环境的情况下，调查了单个组件喷气燃料替代物（N-Decane）的自由变形液滴的蒸发行为。这些研究利用接口捕获直接数值模拟（DNS）。为了验证求解器的准确性，将结果与Abramzon和Sirignano的相关性进行了比较（Int。Heatand Mass Transfer，1989年），发现非常吻合，最高差额为$ 5 \％$。 \ textColor {black} {实施了一种准稳态蒸发方法来模拟此问题。}结果表明，归一化总蒸发率（$ {\ dot {m}} _ {nd} $）对Weber数量低$ re Re $流量的依赖性较弱。但是，总蒸发率与$ $ $ $ re $之间存在很强的相关性。 $ 20 \％$增强$ {\ dot {m}} _ {nd} $在$ we = 12 $（高度变形的形状）时，与$ we = 1 $ ph $ re re = 120 $相比。 在这些情况下，发现局部蒸发通量在液滴上的分布与其曲率成正比，直到流动分离点与Tonini和Cossalli的液滴蒸发理论一致（国际热与传播杂志2013年），Palmore（《热传输杂志》 2022年）。除了流分离点之外，蒸发通量分布取决于液滴下游的边界层发展和流动进化。对于高度变形的液滴，较大的尾流区域会产生有利的燃油蒸气梯度，并促进液滴唤醒中的混合，从而更高的蒸发通量。
This work covers the effect of droplet deformation on its evaporation rate under convective flow conditions. The evaporation behavior of a freely deforming droplet of single component jet fuel surrogate, n-decane, is investigated by varying Weber number ($We$) from $1-12$ and Reynolds number ($Re$) from $25$ to $120$ under high-pressure environment. These studies utilize interface capturing Direct Numerical Simulation (DNS). To validate the accuracy of the solver, the results are compared against correlations by Abramzon and Sirignano (Int. Journal of Heat and Mass Transfer, 1989) and are found to be in good agreement with a maximum difference of $5 \%$. \textcolor{black}{A quasi-steady evaporation approach is implemented to simulate this problem.} The results suggest a weak dependency of normalized total evaporation rate (${\dot{m}}_{ND}$) on Weber number at low $Re$ flow. However, a strong correlation is seen between the total evaporation rate and $We$ at high $Re$. $20 \%$ enhancement in ${\dot{m}}_{ND}$ is observed at $We=12$ (highly deformed shape) when compared to $We=1$ at $Re=120$. In these cases, the distribution of local evaporation flux on the droplet is found to be proportional to its curvature up to the point of flow separation which agrees with low $Re$ theories on droplet evaporation by Tonini and Cossalli (International Journal of Heat and Mass Transfer 2013), Palmore (Journal of Heat Transfer 2022). Beyond the flow separation point, evaporation flux distribution depends on the boundary layer development and flow evolution downstream of the droplet. For highly deformed droplets, a larger wake region creates favorable fuel vapor gradients and promotes mixing in droplet wake, hence higher evaporation flux.
