离心风机内泄漏数值优化研究

利用流体分析软件ANSYS CFX对某一高效离心风机进行了内部三维数值模拟,得到其流体动力学特征和内泄漏损失特征.根据理论公式对风机泄漏量进行了估算,比较理论计算泄漏量与数值模拟计算泄漏量.首先,在设计工况点对未加装防涡圈的风机进行数值计算,发现在蜗壳内部有一些大的旋涡,并观察到一些重要的流动现象.然后,对加装防涡圏后的离心风机进行整机数值模拟,结果表明,加装防涡圏后蜗壳内部的漩涡明显减小,漩涡强度减弱,流场得到改善,泄漏损失明显减小.最后,对不同间隙的加装防涡圈后的风机进行数值模拟,结果显示,随着间隙的减小,泄漏量明显减小,所以在保证安全运行的条件下,间隙应尽可能小.

Numerical Study on the Internal Leakage of Centrifugal Fan

The 3-D numerical simulation of centrifugal fan was conducted by ANSYS CFX to investigate the internal flow field and internal leakage losses.The leakage of fan was estimated according to the theoretical formula.The theoretical leakage and simulated leakage were compared.The numerical investigation on the internal flow field at the designed point was performed.The results showed that there were large vortexes and air leakage existed in the clearance between the inlet and blade.Many complex phenomena have been observed.To break the vortexes and reduce the internal leakage losses,a type of arc anti-vortex rings was installed in the fan.Then the numerical investigation with the rings was conducted.It was found that the vortexes decreased significantly.The vortex strength weakened.The flow field was improved and the leakage losses reduced.The numerical simulation of the fan with different clearance between the inlet and blade was conducted.The results showed that the leakage losses reduced significantly with the decrease of the gap.The gap should be as small as possible under the conditions of safe operation.