Study of the influence of structural parameters on the operating characteristics of a new type of surge soot blower in the closed-ended system

结构参数对闭口体系新型激波吹灰器工作特性的影响研究

School of Power and Energy, Northwestern Polytechnical University, Xi'an 710129, China

Received: 16 March 2023

Abstract

Boiler soot blower can effectively realize the removal of the accumulated ash inside the boiler, improve the operating efficiency of the boiler, which is of great significance to the safe operation of the boilerSPG-type surge soot blower is a new type of high-performance soot blower with a closed-port system which is developed on the basis of the traditional surge soot blowers.The use of numerical methods to validate the feasibility and analyze the working characteristics of this device can provide a reference for the practical application and improvement. Based on CFD technology, the SPG-type surge soot blower is taken as the research object, and the real movement process of the piston inside the device is simulated using dynamic mesh technology, and the dynamic process of continuous change of the flow field inside the SPG-type surge soot blower is simulated and calculated using Fluent software, and the structural parameters of the nozzle, the combustion chamber, and the pressure accumulator are adjusted, so as to obtain the influence law of changes in structural parameters of each component on the exhaust characteristics by monitoring at the outlet. By adjusting the structural parameters of the nozzle, combustion chamber and pressure accumulator, the structural parameters of each component are monitored at the outlet to obtain the influence law of the change on the exhaust characteristics and the working characteristics. The results show that: when the nozzle L/D ratio is increased from 2 to 4, the peak value of the outlet parameter shows a hysteresis phenomenon, but the peak value of the pressure and the peak value of the velocity get a significant increase, and the expansion loss can be reduced by changing the expansion section of the nozzle to a straight one, so it is a better solution to increase the nozzle L/D ratio appropriately and connect the straight pipe directly; the shortening of the spacing between radial and axial wall surfaces of the combustion chamber can increase the peak value of the outlet pressure, but the increase of the peak value of the pressure can be greater by shortening the axial distance. The increase in peak pressure is greater; in the pressure accumulator, removing the damping device increases the pressure less, and cannot slow down the piston reset, so that the discharge gas is reduced, and after removing the restrictor, the nozzle outlet pressure is greatly increased, but its peak duration becomes shorter.

摘要

锅炉吹灰器可以有效实现清除锅炉内部的积灰, 提高锅炉运行效率, 对锅炉安全运行具有重要意义。SPG型激波吹灰器是在传统激波吹灰器基础上发展而来的闭口体系新型高性能吹灰器, 使用数值方法对该装置的可行性进行验证, 并分析工作特性, 可以为实际应用与改进提供参考。基于CFD技术, 将SPG型激波吹灰器作为研究对象, 使用动网格技术对设备内活塞的真实运动过程进行仿真模拟, 利用Fluent软件模拟计算SPG型激波吹灰器内部流场的连续变化这一动态过程, 并通过调整喷管、燃烧室以及压力蓄能器的结构参数, 在出口处监测得到各部件结构参数变化对排气特性的影响规律, 获取其工作特性。结果表明: 喷管的长径比从2增加到4时, 出口参数峰值出现滞后现象, 但压力峰值与速度峰值获得显著提升, 且喷管的扩张段改为直管可以降低膨胀损失, 适当增加喷管长径比并直接连接直管是一种较好的方案; 燃烧室径向和轴向壁面之间的间距缩短均可使出口压力峰值提高, 但轴向距离缩短压力峰值增加幅度更大; 在压力蓄能器中, 去除阻尼装置压力提升较少, 且无法减缓活塞复位, 使排出气体减少, 去除限位器后喷管出口压力大幅提高, 但其峰值持续时间变短。