Pressure drop is often calculated using the Ergun equation, which considers both laminar and turbulent flow conditions: ΔP = (150 * (1-ε)²/ε³) * (μ * u₀/dp²) + (1.75 * (1-ε)/ε³) * (ρ * u₀²/dp) where ΔP is the pressure drop, ε is the void fraction, μ is the fluid viscosity, u₀ is the superficial velocity, dp is the particle diameter, and ρ is the fluid density.
