Study on the influence of outlet diameter on the out-field pressure action characteristics of pulse detonation cleaning device

出口直径对脉冲爆震清灰装置外场压力作用特性的影响研究

School of Power and Energy, Northwestern Polytechnical University, Xi'an 710072, China

Received: 26 April 2023

Abstract

Pulse detonation cleaning technology is an efficient cleaning technology that is used inert shock waves generated by decoupling the detonation to remove ash and deposits. And it has great advantages in the field of furnace cleaning. In order to investigate the pressure distribution characteristics outside the detonation cleaning device and to explore the effect of the device outlet diameter on the pressure distribution characteristics, numerical simulations and experimental studies of pulse detonation cleaning device with using propane-air as the fuel has been carried out. The numerical simulation and experimental study on pulse detonation cleaning device by using propane-air as the fuel has been carried out. The results show that: as the propagation distance increases, there is a trend for the out-field arc shaped shock wave to transform into plane wave, and the applied pressure tends to be similar from the axis outward, and the time it acts on the ash accumulation surface also tends to be similar. When the external shock wave acts on the ash accumulation surface of the non-convective tube bundle, except for the positive reflection at the axial opposite position, which generates one pressure peak, the other positions mainly generate two pressure peaks due to oblique reflection. The ratio (diameter ratio) between the diameter of the tail outlet and the diameter of the detonation chamber is 1, the pressure peak of inert shock wave in the out-field is the largest. Increasing or decreasing the out diameter of the tail will weaken the action of the inert shock to different degrees. For diameter ratio smaller than 1, the pressure peak of the inert shock increases with increasing diameter ratio, while for diameter ratios larger than 1, decreases with increasing diameter ratio.

摘要

脉冲爆震清灰技术是一种利用爆震波解耦产生的冲击波清除积灰的高效清洁技术, 在炉内清洁领域具有巨大优势。为探究爆震清灰装置外场压力作用特性及装置出口直径对其压力作用特性的影响, 以丙烷-空气为燃料, 针对某型脉冲爆震清灰装置开展数值仿真与试验研究。结果表明: 随着传播距离的增加, 边缘处的弧状冲击波存在转变为平面波的趋势, 冲击波的作用压力峰值趋于相近, 且作用压力峰值的到达时间也趋于相近。当外场冲击波作用于非对流管束积灰面时, 除爆震室轴线正对处发生正反射而产生一道压力峰值外, 其余位置主要因发生斜反射而产生2道压力峰值。尾段出口直径与爆震室直径比值(直径比)为1时外场冲击波作用压力峰值最大, 出口直径的增加或减小均会不同程度地削弱外场冲击波的压力峰值, 直径比小于1的结构对外场冲击波的削弱效果最为显著, 直径比大于1的结构削弱效果较次之; 在直径比小于1时冲击波作用压力峰值随直径比增大而增大, 当直径比大于1时冲击波作用压力峰值随直径比增大而减小。