Two-Phase Flow Pressure Drop Calculator

System analysis using Lockhart-Martinelli, Beggs & Brill, and Hagedorn & Brown correlations.

Purpose: Calculate pressure drop and hydraulic parameters for two-phase (liquid-gas) flow in pipes using established industry correlations.

System & Pipe Parameters

Phase Properties & Flow Rates

Actions

Primary Results

Total Pressure Drop: -
Outlet Pressure: -

Pressure Drop Breakdown

Frictional Drop: -
Gravitational Drop: -
Accelerational Drop: -

Hydraulic Details

Pipe Internal Diameter: -
Liquid Holdup (Hβ‚—): -
Mixture Velocity (Inlet): -
Superficial Liquid Velocity: -
Superficial Gas Velocity (Inlet): -

Flow Pattern

-

Technical Notes

Variable Definitions

  • L: pipe length (m); D: internal diameter (m); Ξ΅: absolute roughness (m).
  • qL: liquid volumetric flow (mΒ³/s) at operating conditions.
  • qG,std: gas volumetric flow at standard conditions (SmΒ³/s); qG: actual at pressure (mΒ³/s).
  • ρL, ρG: densities (kg/mΒ³); ΞΌ: viscosities (PaΒ·s).
  • Vsl, Vsg: superficial velocities (m/s); Vm=Vsl+Vsg.
  • HL: liquid holdup (–).
  • Ξ”Pf: frictional drop (Pa); Ξ”Pg: gravitational drop (Pa); Ξ”Pa: accelerational drop (Pa).

Formulas / Logic

  • Internal diameter: ID = (OD βˆ’ 2Β·t) from the built-in pipe database (screening).
  • Standard β†’ actual gas rate: assumes ideal-gas scaling at constant T and Z: qG = qG,stdΒ·Pstd/P.
  • Friction factor: laminar f=64/Re, turbulent uses an explicit Colebrook-type approximation: fβ‰ˆ0.25/[log10(Ξ΅/3.7D + 5.74/Re^0.9)]Β².
  • Beggs & Brill: flow pattern from Fr and Ξ»L; holdup HL with inclination correction; two-phase friction multiplier via exp(S).
  • Lockhart–Martinelli: single-phase dpL, dpG β†’ Martinelli parameter X and φ²; uses C based on laminar/turbulent combinations (screening).
  • Hagedorn & Brown: implemented as a simplified vertical-flow approximation (screening).
  • Total drop: Ξ”P = Ξ”Pf + Ξ”Pg + Ξ”Pa. Acceleration is estimated from change in mixture velocity with pressure.
This calculator is intended for preliminary checks. For design-critical cases, validate with a calibrated multiphase simulator and/or vendor/industry methods.

Assumptions / Notes

  • Gas actual flow uses ideal-gas scaling; temperature, Z-factor and density variation along the pipe are not rigorously modeled.
  • Minor losses (fittings, valves, restrictions) are not included unless accounted by equivalent length in L.
  • Beggs & Brill is applicable across inclinations; Lockhart–Martinelli is best for near-horizontal; Hagedorn & Brown for near-vertical upward.
  • For strongly compressible/high Ξ”P cases, iterate properties (ρG, ΞΌG, Z, T) along the line using a dedicated tool.

Standards / References

  • Beggs, H.D. & Brill, J.P. (1973): two-phase flow in pipes (inclination model).
  • Lockhart, R.W. & Martinelli, R.C. (1949): two-phase frictional pressure drop (horizontal).
  • Hagedorn, A.R. & Brown, K.E. (1965): vertical multiphase flow correlation (oil/gas wells).
  • Common engineering references: GPSA Engineering Data Book, multiphase flow handbooks, and vendor guidance.
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