| Parameter | Value |
|---|
Common Fluid calculations with flow analysis for SFX
Step 1: Calculate your hose system first to determine maximum flow capacity
Step 2: If hose max flow is less than your pump flow, use the hose flow value in the cylinder calculation. Also reduce the cylinder pressure by the hose pressure drop to get actual cylinder performance.
This ensures your cylinder calculations reflect real-world flow limitations and available pressure
Use this flow rate in your cylinder calculation:
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If this is less than your pump flow rate, your hose system is the limiting factor.
When enabled: reduces system pressure by hose pressure drop, and limits pump flow to hose capacity
⚠️ BUCKLING WARNING: Rod diameter is insufficient for compression load!
🔴 Red: Limited by port size (flow limit)
🟢 Green: Limited by pump flow rate
Gas expansion simulation modeling compressed gas expansion from reservoir to piston cylinder with choked-flow orifice. Uses ideal gas laws and flow rate limitations.
Based on Alex (Lec) Fabre's excellent cannon calculator
Set in System Settings above
Max Throw Height: Calculated assuming vertical launch with no aerodynamic drag. Actual height will be lower due to air resistance.
Simulation Method: Uses discrete time steps (dt=0.001s) to model gas transfer through orifice. Choked flow occurs when reservoir pressure exceeds critical ratio.
Energy Losses: System efficiency parameter accounts for friction, heat transfer, and incomplete gas expansion. Typical values: 70-80%.
Based on Alex (Lec) Fabre's excellent cannon calculator
Hose & Elbow Flow Capacity Calculator:
Maximum Flow Calculation Method:
• Flow capacity is limited by the LOWER of two constraints:
1. Velocity Limit: User-selectable from 4.5 m/s (continuous) to 9.1 m/s (peak/transient)
2. Pressure Drop Limit: 10% of system pressure (industry standard for hydraulic hoses)
• For short hoses at typical system pressures, the velocity limit usually controls
• For long hoses or low system pressures, the pressure drop limit may control
Pressure Drop Calculation:
• Uses Swamee-Jain equation (explicit Colebrook-White approximation) for friction factor
• Darcy-Weisbach equation: ΔP = f × (L/D) × (ρv²/2) for straight pipe pressure drop
• Hose roughness: 0.045mm (smooth-bore hydraulic hose typical value)
• Accounts for both laminar (Re < 2300) and turbulent (Re ≥ 2300) flow regimes
• Elbow losses: K-factor = 0.9 per 90° elbow (modern hydraulic fittings)
Laminar Only Flow:
• Uses Hagen-Poiseuille equation: Q = (π × D⁴ × ΔP) / (128 × μ × L)
• Shows maximum flow that maintains laminar conditions (Re < 2300)
• Capped at Reynolds number 2300 if pressure-based calculation exceeds laminar limit
Velocity Limit Guidelines (empirically derived from industry experience):
• 4.5 m/s (15 fps): Continuous flow, maximum hose life, minimal erosion
• 5.5 m/s (18 fps): Industry standard for typical applications
• 6.0 m/s (20 fps): Intermittent flow, acceptable for periodic operation
• 7.6 m/s (25 fps): Short duration events (seconds to minutes)
• 9.1 m/s (30 fps): Peak/transient events only (fractions of a second)
Assumptions & Limitations:
• Fluid properties based on standard conditions (20°C, atmospheric pressure)
• Does not account for entrance/exit losses or fittings other than 90° elbows
• Assumes steady-state flow (no surge, water hammer, or transient effects)
• Does not include coupling losses (typically ~5% of hose loss per coupling pair)
Hydraulic Cylinder Calculator:
• Force calculations based on Pascal's law (Force = Pressure × Area)
• Rod buckling analysis uses Euler's critical load formula
• Assumes incompressible fluid and rigid cylinder construction
• Velocity and time calculations assume constant flow rate
• Port velocity uses continuity equation and total port area
• Does not account for seal friction, internal leakage, or dynamic effects
Gas Expansion Cannon Calculator:
• Ideal gas law (PV = nRT) with γ = 1.4 for air/nitrogen
• Choked flow calculation for orifice restrictions
• Isothermal expansion assumed (T = 293K / 20°C)
• Energy transfer efficiency accounts for friction and heat losses
• Max throw height calculated from kinetic energy conversion (KE = PE)
• Does not account for aerodynamic drag, barrel friction variations, or valve opening dynamics
Based on Alex (Lec) Fabre's excellent cannon calculator