Study on Flame Acceleration Phenomena at Gas Explosions

气体爆炸火焰加速现象研究

基本信息

批准号：
60490005
负责人：
HIRANO Toshisuke
金额：
$ 3.58万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

项目摘要

The turbulence growth at flame fronts far from solid walls, which has remained ambiguous in spite of its importance for understanding overall flame acceleration at gas explosions, has been studied and the following results have been obtained.1. Two types of flame propagation test apparatus were designed to induce a shear flow near a propagating flame front and velocity change in the direction normal to the flame front. By using these apparatus, turbulence at a propagating flame front was caused, and its variation was recorded by high speed schlieren photography and examined. At the same time, the pressure fluctuation in the combustion chamber is recorded.2. The obtained high-speed schlieren photographs were analyzed using film analyzer and computer, and comparing the result to the pressure record, a close relation was found between the flame acceleration or deceleration and pressure fluctuation.3. By examining the motions of turbulent premixed flames under various conditions, it was revealed that the flame front turbulence depends largely on the neighboring flow field. In the flow field for flame acceleration, very rapid development of flame front turbulence was observed, while in the flow field for flame retardation, flame front turbulence was observed to be suppressed and its scale became small. These results coincide well with those of a computer simulation.4. The pressure-time diagrams were predicted by considering the effects of flame acceleration on pressure increase in gas explosions. The results indicate that the pressure-time diagrams become close to those at actual gas explosions by considering the turbulence growth and that turbulence growth increases the maximum pressure and reduces the time to it.

已经研究了远离固体壁的湍流增长，尽管它对理解气体爆炸时总体火焰加速的重要性仍然含糊不清，但已得到研究，并获得了以下结果。1。设计了两种类型的火焰传播测试设备，以诱导传播的火焰前部附近的剪切流，并在垂直于火焰前的方向上变化。通过使用这些设备，引起了传播火焰前沿的湍流，并通过高速Schlieren摄影记录其变化并进行了检查。同时，记录了燃烧室中的压力波动2。使用胶片分析仪和计算机分析了获得的高速Schlieren照片，并将结果与压力记录进行比较，在火焰加速或减速和压力波动之间发现了密切的关系。3。通过在各种条件下检查湍流预混合火焰的运动，可以发现火焰前湍流在很大程度上取决于相邻的流场。在火焰加速度的流场中，观察到火焰前湍流的非常快速的发展，而在火焰迟缓的流场中，观察到火焰前湍流被抑制，其尺度变小。这些结果与计算机模拟的结果很好。4。通过考虑火焰加速度对气体爆炸压力增加的影响，可以预测压力时间图。结果表明，压力时间图通过考虑湍流的生长和湍流生长增加了最大压力并减少了时间的时间来接近实际气体爆炸处的压力图。