叶顶改型对双级轴流风机性能影响的仿真研究

Simulation of Blade Tip Grooving Effect on Performance of Twin-stage Variable-pitch Axial Fan

针对双级动叶可调轴流风机,提出了从压力面向吸力面开斜槽的叶顶改型措施,模拟了不同斜槽对风机性能的影响,确定了性能优良的改型方案;比较了双级叶轮单独和同时改型时的性能和内流特征。结果表明:两种改型措施均可有效提高风机性能,性能总体提升效果依次为Ⅰ级叶轮叶顶改型、同时改型和Ⅱ级叶轮叶顶改型;虽双级叶顶同时改型后的全压提升最大,但高效区较窄;叶顶改型后吸力面上的静压明显降低,叶顶泄漏损失减小;考虑到变工况运行,Ⅰ级叶轮叶顶改型为优选方案。

For a twin-stage variable-pitch axial fan, a novel blade tip treatment carving a chute from the pressure side to suction side is proposed, and fan performance under different blade tip treatments is simulated to determine the excellent treatment. The effects of blade tip grooving in a single stage or both stages on fan performance and internal dynamics are examined. Numerical results show that both blade tip treatments can improve the fan performance; the overall promotion of fan performance illustrates that the best scheme is the blade tip grooving in the first stage followed by the blade tip grooving in both stages and in the second stage, respectively. Although the tip grooving in both stages enhances the full pressure rise most effectively, the domain of high efficiency is shrunk. After blade tip grooving, the static pressure reduces notably in the suction side and the tip leakage loss declines distinctly. Considering the requirements of varying-load operation, the blade tip grooving in the first stage is a preferred scheme.