Solving ACC Fan Blade Failures acc （解决ACC ACC风扇叶片故障）.pdfVIP

Solving ACC Axial Fan Wind Related Problems Prepared for ACCUG Conference October 16, 2013 Las Vegas, Nevada By Martin J. Cuerdon P.E. 10/16/2013 Advanced Analytical Solutions, LLC 1 Axial Fan Design Attributes Axial Fans efficiently move large volumes of air with relatively low pressure rise. These attributes would seem to make Axial Fans ideal for ACC service. Unfortunately, Axial Fans with intake air flowing at right angles to the fan axis, i.e., crosswinds, violates a basic Axial Fan design assumption: Axisymmetric Intake Flow. Modifying the Asymmetric Intake Flow is the key to minimizing ACC Fan Problems. 10/16/2013 Advanced Analytical Solutions, LLC 2 ACC Axial Fan Wind Related Problems 1. Degradation of Volumetric Flow above 3 m/sec 2. Fan Blade Vibrations caused by Aerodynamic Excitation due to Flutter and Stall Conditions 3. Structural Vibrations Transmitted to the Fan Bridge 4. Fan Blade Structural/Fatigue Failure 5. Fan Noise Accentuated 6. Plume Recirculation Issues Issues 1 through 5 are not unique to ACC’s; they are due to classic Axial Fan Inlet Flow Distortion and Asymmetry conditions. Issue 6 is ACC specific but is partially due to the decreased plume vertical velocity as a result of Issue 1. 10/16/2013 Advanced Analytical Solutions, LLC 3 Classic Axial Fan Flow Distortion and Asymmetry “Distorted flows arising from upstream air-turning circumstances are, however, unavoidable in many instances. For example, a fan taking air from the free atmosphere will be subj