How is centrifugal force on a fan blade calculated?

Centrifugal force F = m × R × ω², where m is blade mass in kg, R is the distance from the rotation axis to the blade center of gravity in meters, and ω = 2π·n/60 is angular velocity in rad/s. The result is in Newtons.

What is the force-to-weight ratio and why does it matter?

The force-to-weight ratio is centrifugal force divided by the blade weight (m×g). It tells you how many times the gravitational force the blade experiences. A ratio of 1000 means the blade 'feels' 1000× its own weight. This is critical for blade root stress, fastener design, and fatigue life assessment.

What is a safe tip speed for industrial fans?

Typical maximum tip speeds: carbon steel impellers 80–120 m/s, stainless steel 60–90 m/s, aluminum 100–150 m/s, FRP/fiberglass 60–80 m/s. Higher tip speeds increase centrifugal stress and noise. Critical applications may limit tip speed to 60 m/s.

Why do ID fans experience more centrifugal force than FD fans?

ID (Induced Draft) fans typically handle hot, dirty gas and have larger, heavier blades at greater radii than FD (Forced Draft) fans. Combined with similar or higher speeds, this results in significantly greater centrifugal forces on ID fan blades.

How does centrifugal force relate to fan balancing?

Centrifugal force from unbalance (uneven mass distribution) causes vibration. Even a small mass difference between blades creates a net unbalance force at the shaft. Proper balancing ensures the centrifugal forces from all blades cancel out, leaving minimal net force on the bearings.

免費工程工具

風機葉片離心力計算器

計算 ID 與 FD 風機葉片上的離心力。取得每片葉片受力、總受力、受力與重量比，以及葉尖速度。

ID / FD 風機每片葉片受力葉尖速度

結果

每片葉片受力

—

每片葉片受力 (kN)

—

受力與重量比

—

總受力（所有葉片）

—

葉尖速度

—

風機葉片上的離心力

m — 葉片質量 (kg)
R — 自軸心至葉片質心的距離 (m) — 請輸入 mm，系統將自動轉換
ω = 2π·n/60 — 角速度 (rad/s)

受力與重量比

葉尖速度

葉尖速度係以葉片質心半徑計算。若需實際葉輪葉尖速度，請使用外側葉尖半徑。

實務範例

範例 — ID 風機葉片

已知： 葉片質量 = 15 kg，質心半徑 = 800 mm，轉速 = 1485 RPM

ω = 2π × 1485 / 60 = 155.5 rad/s

F = 15 × 0.8 × 155.5² = 290,340 N = 290.3 kN

受力/重量 = 290,340 / (15 × 9.81) = 1,972×

質心處葉尖速度 = 0.8 × 155.5 = 124.4 m/s

⚠️ 注意： 此等受力為作用於葉片根部之單片葉片受力。軸承所受淨受力取決於動平衡品質 — 理想狀況下，所有葉片受力應相互抵消。葉片間之質量差異會產生不平衡力，此力即為動平衡校正過程中所測得之不平衡力。