催化重整反应对层流火焰传播速度的影响

通过对冲火焰实验台测量了不同当量比下的甲烷与空气的预混气和经预催化后的预混气的层流火焰传播速度。结果表明,当甲烷和水蒸气经过催化重整反应后,预混气的火焰传播速度明显提高。同时,反应产生的氢气还扩展了甲烷的火焰传播界限(贫限)。此研究从实验角度证明催化重整反应产生的氢气对烃类燃料的火焰传播和稳定均有积极的影响。

基于Timoshenko梁理论的回传射线矩阵法在传感器优化布置中的应用研究

由于结构存在阻尼现象,弹性波在传播过程中信号强度必然会随传播距离而衰减。据此提出弹性波极限传播距离与传感器极限布置间距概念,考虑到在高频率处剪切变形引起的转动惯量对结构动力特性的影响比较大,基于Timoshenko梁理论,结合经典回传射线矩阵法,提出使用局部散射矩阵确定结构损伤检测中的传感器布置极限间距,并将其应用到传感器优化算法中。针对指定检测系统,以桥梁结构Benchmark模型为例,验证算法的有效性。

Heat Transfer with Flow and Phase Change in an Evaporator of Miniature Flat Plate Capillary Pumped Loop

An overall two-dimensional numerical model of the miniature flat plate capillary pumped loop （CPL） evaporator is developed to describe the liquid and vapor flow, heat transfer and phase change in the porous wick structure, liquid flow and heat transfer in the compensation cavity and heat transfer in the vapor grooves and metallic wall. The entire evaporator is solved with SIMPLE algorithm as a conjugate problem. The effect of heat conduction of metallic side wall on the performance of miniature flat plate CPL evaporator is analyzed, and side wall effect heat transfer limit is introduced to estimate the performance of evaporator. The shape and location of vapor-liquid interface inside the wick are calculated and the influences of applied heat flux, liquid subcooling, wick material and metallic wall material on the evaporator performance are investigated in detail. The numerical results obtained are useful for the miniature flat plate evaporator performance optimization and design of CPL.