基于SPH方法的凝胶燃料单滴微爆过程模拟  

Simulation on Single Gelled Fuel Droplet's Micro Explosion Process Based on SPH Method with Fully Variable Smoothing Lengths

作　　者：强洪夫 张林涛 陈福振 刘虎 石超 

机构地区：[1]火箭军工程大学动力工程系,陕西西安710025

出　　处：《含能材料》2017年第5期372-378,共7页Chinese Journal of Energetic Materials

基　　金：国家自然科学基金资助(51276192)

摘　　要：为探究凝胶燃料单滴微爆过程中液滴形态和物理量变化规律,采用光滑粒子流体动力学(SPH)方法对JP-8金属凝胶液滴的微爆过程进行数值模拟研究。引入完全变光滑长度SPH方法解决气泡膨胀过程中密度梯度和光滑长度梯度变化剧烈的问题。采用修正JCD(Johnson-Cook Damage)强度模型模拟了弹性胶凝剂膜。模拟了凝胶液滴微爆过程中,内部气泡生长、膨胀、破壳、喷射等过程。得到了气泡变形过程中液滴内部压力和胶凝剂膜的应力变化特性。探索了凝胶液滴微爆过程中液滴半径、压力、拉伸应力、表面张力等物理量的变化规律。数值模拟结果显示,随着时间的推移,凝胶液滴体积逐渐膨胀,压力震荡上升,当直径膨胀比D/D0达到1.4时,胶凝剂膜破裂,液滴体积迅速缩小,压力急剧下降。对于多气泡凝胶液滴,大气泡相对小气泡膨胀更快,且大气泡产生对壁面的压力更大,导致胶凝剂膜在靠近大气泡附近破裂,破裂时间相较于单一气泡有所缩短。数值模拟结果与实验结果相吻合,揭示了凝胶液滴微爆过程的内在机理,验证了SPH算法在解决此类问题上的有效性。To explore the changing rule of morphology and physical quantity of the droplet in the micro-explosion process of single gelled fuel droplet, numerical simulation study of the micro-explosion process of JP-8 metally gelled fuel droplet was carried out by smoothed particle hydrodynamics （SPH） method. The problem of severe changes of density gradient and smoothing length gradient in the process of bubble expansion was solved by introducing the full variable smoothing lengths SPH method. The elastic gelatinizer membrane was simulated by the modified JCD （Johnson-Cook Damage） strength model. The growth, expansion, broken shell, jet etc.processes for internal bubble in the micro-explosion process of gelled droplet were simulated. The variation characteristics of internal pressure of droplet and stress of gelatinizer membrane in the bubble deformation process were obtained. The changing rules of droplet′s radius, pressure, tensile stress and surface tension etc. physical quantities in the micro-explosion process of gelled fuel droplet were explored. The numerical simulation results show that the droplet′s volume expands gradually and pressure increases in pulse as time goes, and gelatinizer membrane breaks and the droplet′s volume decreases rapidly when diameter ratio D/D0 reaches 1.4; For the multi-bubble gel droplet, the large bubble expands faster than the small bubble, and generates larger pressure on the wall, leading to the gelatinizer membrane fractures near the big bubble, and the rupture time is shortened compared with the single bubble. The numerical simulation results are in agreement with the experimental ones, which reveals the inherent mechanism of the droplet micro explosion process and verifies the effectiveness of the SPH algorithm in solving such problems.

关 键 词：凝胶燃料 光滑粒子流体动力学(SPH) 微爆过程 

分 类 号：TK16[动力工程及工程热物理—热能工程]