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Injection & Stripping Point Hydraulics Calculator

Analyze hydraulic effects when liquid is injected or stripped at a pipeline midpoint. Determine mixed fluid properties, velocity changes, and upstream/downstream pressure profiles.

Injection & Stripping Point Hydraulics
Analyze hydraulic effects when liquid is injected or stripped at a midpoint along a pipeline. Calculate mixed fluid properties, velocity changes, and upstream/downstream pressure profiles using Darcy-Weisbach friction loss.

Operation Type

Upstream Fluid

cP

Injection Fluid

cP

Flow Parameters

(same unit)
psig

Pipe Parameters

in
in
in

Pipeline Geometry

miles
miles
ft
ft

Results

Enter pipeline and fluid parameters, then click Calculate.

Formula Reference

Darcy-Weisbach:

ΔP = f(L/D)(ρV²/2gc)/144

Volume Mixing (SG):

SG_mix = (Q₁·SG₁ + Q₂·SG₂)/(Q₁ + Q₂)

Velocity:

V = 0.4085·Q/d²


Standards: Darcy-Weisbach, Colebrook-White (1939), Crane TP-410

Frequently Asked Questions

What does the injection and stripping point hydraulics calculator do?

This calculator analyzes hydraulic effects when liquid is injected or stripped at a pipeline midpoint. It determines mixed fluid properties, velocity changes, and upstream/downstream pressure profiles using Darcy-Weisbach friction loss.

How are mixed fluid properties calculated at an injection point?

Mixed specific gravity is calculated by volume-weighted average: SG_mix = (Q₁×SG₁ + Q₂×SG₂)/(Q₁ + Q₂). The calculator also computes the resulting downstream velocity and Reynolds number changes.

What is the difference between injection and stripping operations?

Injection adds fluid at a midpoint, increasing downstream flow rate and potentially changing fluid properties. Stripping removes fluid, decreasing downstream flow. Both operations affect pressure profiles, velocities, and friction losses upstream and downstream.

Why must the pipeline be analyzed as two separate sections?

Injection or stripping creates a hydraulic discontinuity where flow rate, velocity, and fluid properties change. Treating the pipeline as a single section produces incorrect pressure drop and velocity calculations downstream of the connection point.

What is erosional velocity and why does it matter at injection points?

Erosional velocity is the maximum allowable velocity before pipe wall damage occurs, calculated per API RP 14E as Ve = C/√ρ. At injection points, increased downstream flow can push velocity above erosional limits, requiring larger downstream pipe diameter.