Minimum Fluidization Velocity Calculator

Minimum Fluidization Velocity Formula

Worked Example

500 µm sand (2650 kg/m³) fluidized by air:

1. Ar = d_p³ ρ_f (ρ_p − ρ_f) g / μ² = 12029.96667
2. Re_mf = √(33.7² + 0.0408 Ar) − 33.7 = 6.630046367 (Wen and Yu)
3. U_mf = Re_mf μ/(ρ_f d_p) = 0.198901391 m/s

Re_mf: 6.630046367 · Bed pressure drop per height (1 − ε)(ρ_p − ρ_f)g: 14291.6004 Pa/m

GATE tip

For air at room temperature use μ = 1.8 × 10⁻⁵ Pa·s (0.018 cP) and ρ = 1.2 kg/m³.

More Fluid Mechanics and Mechanical Operations Calculators

• Ergun Equation Calculator

  ΔP/L = 150μV₀(1 − ε)²/(ε³d²) + 1.75ρV₀²(1 − ε)/(ε³d)

  d = φ_s d_p, V₀ superficial velocity

  Example: Water at 0.01 m/s through a 1 m bed of 3 mm spheres with ε = 0.4: Pressure drop ΔP = 1484.37 Pa.

  Open the ergun equation calculator →

• Size Reduction Energy Calculator

  W = 10 W_i (1/√P₈₀ − 1/√F₈₀)

  Rittinger E ∝ 1/L₂ − 1/L₁; Kick E ∝ ln(L₁/L₂); sizes in µm

  Example: Grinding from 10 mm to 1 mm with W_i = 13 kWh/t: Specific energy W = 2.81096 kWh/t.

  Open the size reduction energy calculator →

Frequently asked questions

Sources

• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.