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中文核心期刊

阶梯型加速段对旋流喷嘴雾化特性的影响

INFLUENCE OF LADDER TYPE ACCELERATING SECTION ON ATOMIZATION CHARACTERISTICS OF PRESSURE SWIRL ATOMIZER

  • 摘要: 旋流内芯是压力旋流式喷嘴最主要的旋流发生构件, 其几何特征直接影响压力旋流式喷嘴的喷雾特性.目前采用平滑型加速段的旋流内芯导流效率较低.为减小高流量条件下的能量损失, 使喷嘴旋流内芯加速段对喷雾介质产生预旋效应, 增强旋流强度, 本文设计喷嘴旋流内芯加速段为阶梯型, 其下段阶梯相对上段阶梯旋转15°, 旋向与喷嘴旋流槽方向相同.利用粒子动态分析仪(particle dynamics analysis system, PDA) 和高速摄影(charge coupled device, CCD)系统实验研究了加速段结构改进前后喷嘴的喷雾流量、雾场索特尔平均直径(Sauter mean diameter, SMD)、雾滴速度以及喷雾锥角, 并分析了SMD、 雾滴速度的轴向和径向分布特性. 结果表明, 背压差0.08~ 0.46 MPa 范围内, 阶梯型加速段对喷雾介质具有较好的预旋效果.喷嘴的流量提高了48.0% ~ 51.8%; 喷雾的轴向速度提升了31.4% ~ 32.8%, 径向速度提升了1.6% ~ 16.8%; 喷雾锥角减小了4.21°~6.57°; 较高背压差下喷雾下游的SMD减小了9.8%.与平滑型加速段相比, 阶梯型加速段的设计有效地提高了喷嘴的雾化质量.

     

    Abstract: Swirl atomizer inner core is the most important swirling component of the pressure swirling atomizer, the geometric topology of the swirl atomizer inner core directly affects the spray characteristics of pressure swirling atomizer.The current smooth acceleration section of the swirl atomizer inner core has lower flow efficiency.In order to reduce the energy loss, the swirl atomizer core accelerating section with ladder type has been designed to make spray medium pre-swirl and enhance the swirl strength in this paper, the lower part rotates 15° relative to the upper part, and the direction of the rotation is the same as the direction of the swirling slots of the atomizer. Spray flow rate, spray Sauter mean diameter(SMD), spray cone angle and droplet velocity were experimentally investigated by making use of particle dynamics analysis system(PDA) and charge coupled device experimental system(CCD) before and after the structure improvement of the acceleration section, and the axial and radial distributions of SMD and droplet velocity were also analyzed. Under the pressure ranges from 0.08 MPa to 0.46 MPa, the ladder type acceleration section has the better pre-swirl effect. The flow characteristics of the atomizer were increased by 48% to 51.8%; the axial and radial velocity of the spray were increased by 31.4% to 32.8% and 1.6% to 16.8%, respectively.The spray cone angle was reduced by 4.21° to 6.57°, and the SMD at downstream of the spray was decreased by 9.2% under higher pressure conditions.Compared with the smooth accelerating section, the application of ladder type accelerating section is beneficial to improve the quality of atomization.

     

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