煤油液滴在富氧燃气中不稳定燃烧的数值研究

Numerical investigation of kerosene-droplet’s instable combustion in oxidizer-rich gas

关键词:  燃烧稳定性  燃烧化学  数值计算  液氧+  煤油

Key words:  Combustion stability  Combustion chemistry  Numerical calculation  Liquid oxygon~+  Kerosene

摘要:

采用数值分析的方法,对富氧燃气中的煤油液滴的不稳定燃烧过程进行了研究。采用一维轴对称N S方程,考虑了高压实际气体物性和液滴/气团表面气液平衡。计算中空间和时间尺度分别为μm和μs的量级。结果表明,液滴在接近超临界点时,物性的快速变化会引起一定频率的自发振荡;超临界气团对不同压力振荡频率的响应不同;煤油蒸汽的消耗速率对压力振荡的响应不同于蒸发速率的响应,热量释放对压力振荡也具有明显的响应。

Abstract:

Kerosene-droplet’s instable combustion process in oxidizer-rich gas was investigated numerically. One-dimensional spherical symmetrical N-S equations were employed, and the actual property of the gas and gas-liquid equilibrium on the droplet’s surface were taken into account. 10^-6 meter and 10^-6 second magnitude corresponding to space and time were adopted in calculation. The results show that certain frequency unstable vaporization could be aroused even without pressure oscillation. It is due to the rapid physical-chemistry property variation when droplet is heated up and approaches supercritical point. Supercritical gas-mass’s response is decided by the frequency of pressure oscillations. Heat release’s response to the pressure oscillation is different from the vaporization rate. Moreover, its response to pressure oscillations is obvious.