Rijke管内大颗粒煤脉动燃烧特性研究

Study on Pulsating Combustion Characteristics of Large Particle Coal in the Rijke Tube

中文关键词: 脉动燃烧  稳态燃烧  大颗粒煤  燃烧速率  燃烧效率

英文关键词: Pulsating combustion  steady combustion  large coal particles  combustion rate  combustion efficiency.

中文摘要:

      为了促进煤脉动燃烧技术在物料干燥领域的应用，建立了基于感应加热的Rijke型脉动燃烧装置，以直径11.5±0.5 mm的大颗粒煤为对象，分别在脉动燃烧（在热声耦合作用下，燃烧状态参数周期性振荡的燃烧模式，特点是燃烧室内气流压力，温度和速度等呈周期性振荡变化）和稳态燃烧（自然对流或低速通风，燃烧室内气流压力、温度、速度等参数宏观上不随时间产生大的变化）两种工况下进行了燃烧实验。对比分析了两种工况下的大颗粒煤燃烧过程中的形貌变化、质量变化、尺寸变化、煤灰粒径和煤灰分布情况。实验结果表明：在脉动燃烧工况下，振荡气流不断将大颗粒煤表面煤灰剥离，使得大颗粒煤内部与空气得到充分接触，导致大颗粒煤燃烧过程仅有加热、快速燃烧段；大颗粒煤燃烧速率快，颗粒尺寸快速减小，最大燃烧速率为0.63 %/s，是稳态燃烧下速率的1.6倍；大颗粒煤燃烧更彻底，燃烧效率从稳态燃烧的52 %提升至近100 %；大部分煤灰被振荡气流裹挟并以飞灰形式带出，剩余煤灰分散性好。

英文摘要:

      To promote the application of coal pulsating combustion technology in the field of material drying, a Rijke-type pulsating combustion device utilizing induction heating is developed. The experiments are conducted using large-sized coal particles with a diameter of 11.5±0.5 mm under both pulsating combustion (where the combustion process parameters oscillate periodically and a pulsating gas flow is generated in the combustion bed) and steady combustion conditions (where the gas pressure, tem-perature, velocity inside the combustion chamber do not change with time) . Variations of the coal particle morphological shape, mass, particle size, ash size, and its distribution during the large parti-cle coal combustion process under these two conditions were compared and analyzed. The experi-mental findings indicated that under the pulsating combustion condition, continuous removal of the coal ash from the surface of the large-particle coal by the pulsating airflow would facilitate full con-tact between interior unburned coal and fresh air, resulting in a fast combustion process comprising only the initial heating stage and the subsequent rapid combustion stage. Also, the combustion rate of large particle coal was faster, and the particle size decreased more rapidly. The maximum combus-tion rate was 0.63%/s, which was 1.6 times the rate under the steady combustion; Large particle coal combusted more completely, and the combustion efficiency increased from 52% under the steady combustion condition to nearly 100%. Most of the coal ash was carried out as fly ash by the oscillat-ing gas flow, and the remaining coal ash had a good dispersibility.