螺旋形实心锥喷嘴雾化特性试验研究

为了对氨法脱硫用螺旋形实心锥喷嘴的雾化特性进行准确预测,基于高速阴影技术和图像处理方法,对两种不同螺旋升角的螺旋形实心锥喷嘴的流量特性、喷雾场结构特征、雾化角变化规律、破碎长度、液滴空间分布及平均粒径进行分析。结合脱硫常用的空心锥离心式喷嘴,开展了两种喷嘴的稳定性对比分析。结果表明:螺旋形实心锥喷嘴的流量特性与螺旋升角无关,其喷雾场呈螺旋状同心锥面分布,雾化后液滴也呈螺旋形多层次分布,即实心锥分布;螺旋形实心锥喷嘴雾化角在喷注压降大于0.05 MPa时与螺旋形升角有关,与流量和喷注压降无关;考虑螺旋面升角对液滴平均粒径的影响,得到了新的索太尔平均直径(SMD)经验关系式,预测结果与试验结果趋势一致,且螺旋升角越大,液滴平均粒径越小;螺旋形实心锥喷嘴在喷注压降小于0.05 MPa时也能保证稳定雾化,而空心锥离心式喷嘴会出现约为9 Hz的自激振荡现象,喷雾场呈"宝塔形",且具有明显的Klystron效应。

Experimental Study on Spray Characteristics of Spiral Solid Cone Nozzle

In order to accurately predict the spray characteristics of spiral solid cone nozzle in ammonia desulfurization,based on high speed shadow technology and image processing method,these characteristics were systematically analyzed in two spiral solid cone nozzles with different helix angles,such as the flow characteristics,the spray field structure characteristics,the spray angle change rule,the breaking length,the droplet spatial distribution and the average droplet diameter.In addition,combined with another kind of hollow cone centrifugal nozzle commonly used in desulfurization,a comparative analysis of the stability of the two nozzles was carried out.The results show that the flow characteristics of spiral solid cone nozzle are independent of helix rise angle.The spray field is distributed in spiral concentric conical surface,and the droplets are also distributed in a spiral multi level distribution,that is a solid cone distribution.The spray angle of the spiral solid cone nozzle is mainly related to the helix rise angle.When the pressure drop is greater than 0.05 MPa,it has little to do with the flow parameters.For the first time,the influence of the helix angle on the average droplet size was considered,and a new empirical formula of SMD(Sauter Mean Diameter)was obtained.The predicted results are consistent with the experimental results.The larger the helix angle is,the smaller the average droplet size is.Finally,through comparative analysis,it is found that a prominent advantage of the spiral solid cone nozzle is that it can ensure stable spray when the injection pressure drop is less than 0.05 MPa.However,the self excited oscillation phenomenon of 9 Hz is found in the hollow cone centrifugal nozzle.The spray field is in the shape of a pagoda and has an clear Klystron effect.