The Basics of AXIAL FLOW FANS Mechatronics （轴流风扇机电一体化的基础知识）.pdf

The Basics of AXIAL FLOW FANS Hudson Products Corp. Page 1 of 35 The Basics of Axial Flow Fans CONTENTS Page FOREWORD 3 FIGURES 3 NOMENCLATURE 4 1.0 Definition of Axial Fans 6 2.0 Fan Engineering Nomenclature 6 2.1 Fan Engineering Units 8 2.2 Useful Conversion Factors 9 3.0 Fan Selection Criteria 10 4.0 Basic Fan Equations - (I-P Units Only) 11 5.0 Fan Performance Calculation 12 6.0 Some Basic Assumptions 14 Effect of: 6.1 Tip Clearance 15 6.2 Inlet Conditions 16 6.3 Velocity Recovery Stacks 16 6.4 System Resistance 17 6.5 Horsepower 18 6.6 Density 19 6.7 Vibration 20 6.8 Number of Blades 21 6.9 Blade Shape 22 6.10 Seal Disc 23 ® 7.0 Variable Airflow Fans (Auto-Variable ) 23 8.0 Variable-Pitch vs. Variable-Speed 29 9.0 Noise Considerations 29 9.1 Noise-Related Nomenclature 30 9.2 Allowable Fan Noise 31 9.2.1 ACHE Noise 31 9.2.2 Cooling Tower Noise 31 9.3 Predicting Fan Noise 31 9.4 Noise Testing 33 REFERENCES 34 DEDICATION 34 Hudson Products Corp. Page 2 of 35 The Basics of Axial Flow Fans FOREWORD This manual is designed to familiarize users It should be noted that final fan sele