Abstract This study investigated the burning characteristics of PMMA with varied stretch rates under stagnation-point diffusion flames both theoretically and experimentally, focusing on the manner in which the surface energy balance and heat losses affected burning rate with varied stretch rates. The burning rate versus stretch rate was firstly investigated by introducing a modified Spalding B number, where the burning rate was proved to equal the buoyancy or forced flow induced stretch rate to the power of 0.5. At lower stretch rate, burning was largely affected by heat losses, associated with a lower B number, and decreased up to the quenching limit, similar to the microgravity results. At higher stretch rate, burning was controlled by flame radiation with a larger B number and increased burning rate. Additionally, ice bath increased the solid in-depth conduction heat loss due to the lower temperature maintained at the upper surface of the sample, and further influenced the energy balance with a larger heat losses fraction, leading to reduced B number and burning rate. This study provided an insightful investigation of the burning behaviors of stagnation-point diffusion flames with low stretch rates, which was used in a terrestrial environment to simulate microgravity flames.

中文翻译：

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滞点扩散火焰下不同拉伸速率的PMMA燃烧特性

摘要 本研究从理论上和实验上研究了滞点扩散火焰下不同拉伸速率的 PMMA 的燃烧特性，重点研究了表面能平衡和热损失对不同拉伸速率下燃烧速率的影响。首先通过引入修正的斯伯丁 B 数来研究燃烧速率与拉伸速率的关系，其中证明燃烧速率等于浮力或强制流动引起的拉伸速率的 0.5 次方。在较低的拉伸速率下，燃烧在很大程度上受热损失的影响，与较低的 B 值相关，并降低到淬火极限，类似于微重力结果。在较高的拉伸速率下，燃烧由具有较大 B 值和增加燃烧速率的火焰辐射控制。此外，冰浴由于样品上表面保持较低的温度而增加了固体深度传导热损失，并进一步影响能量平衡，热损失分数较大，导致B值和燃烧速率降低。这项研究对低拉伸率的驻点扩散火焰的燃烧行为进行了深入研究，该火焰在陆地环境中用于模拟微重力火焰。