叶片特性和中心风量对一种煤气燃烧器冷态流场的影响

Influence of the Blade Characteristics and Central Air Quantity on the Cold-state Flow Field of a Coal-gas Burner

基于高温煤气燃烧特点和对煤气燃烧器的要求,本研究提出了一种新型煤气燃烧器,并建立了冷态试验台架,利用等温模化方法将燃烧器内部结构及运行工况对流场分布的影响进行了冷态试验。试验表明:叶片的旋流角度为60°时比45°和30°时产生的旋流强度大,有利于高温煤气与配风在燃烧室内的旋流混合效果,但同时旋流衰减也在加快;此外,具有8个叶片的燃烧器比6叶片燃烧器的旋流效果好,但流场阻力大;中心风量从额定工况的0.8倍增加到1.2倍时,旋流对直流的影响减弱,有利于火焰形状的改变;叶片到喷口的距离从65mm减小到零时,旋流效果变的明显,有利于气流混合。冷态试验结果对该燃烧器的优化设计和进一步热态试验提供借鉴和参考。

Based on the specific features of the combustion of high temperature coal gas and its requirements for coal gas burners,presented was a novel type coal-gas burner with a cold-state test rig being set up.A cold-state test was performed of the influence of the inner structure of the burner and the operating conditions on the flow field distribution by employing an isothermal modeling method.The test results show that a bigger swirling intensity will be produced when the swirling angle of the blades is set at 60 degrees than those when it is set at 45 degrees and 30 degrees,favorable for the swirling flow mixing effectiveness of the high temperature coal-gas and the air supplied in the combustion chamber and at the same time also quickening the attenuation of the swirling flow.Furthermore,the swirling effectiveness of a burner with 8 blades is better than that of a burner with 6 blades,however,a bigger resistance may result in the flow field.When the central air quantity increases from 0.8 times provided under the rated operating condition to 1.2 times,the influence of the swirling flow will be weakened on the straight flow,contributing to changing the shape of the flame.When the distance from the blades to the spout is reduced from 65 mm to 0 mm,the swirling effectiveness will become conspicuous,favorable for mixing various gas flows.The cold-state test results can offer reference for the optimized design and further hot-state test of the burner.