Fluid Properties · DWG LS-009

Oil flush Reynolds number calculator

Multi-run flush circuit analysis. Computes the per-run Reynolds number, compares it to the turbulent-flush target for the fluid's ISO VG class, checks pipe/hose pressure limits and flash point, and back-solves the temperature needed to reach the flush target.

Published method (Reynolds number)Last reviewed 14 Oct 2026

Source: Machinery Lubrication: Reynolds number in oil flushing

The turbulent-flush targets by ISO VG class and the back-solved temperature are planning values; follow your flushing procedure.

Reynolds Number & Flush Circuit Analyzer

Fluid

Oil Selection

Operating / Flush Temperature

Kinematic Viscosity (cSt) Auto-filled or manual

Specific Gravity Auto-filled or manual

Pipe / Hose

Conduit Category

Nominal Pipe Size (NPS)

Pipe Schedule / Material

Inner Diameter (auto-filled or override)

Circuit Geometry & System Volume

Pipe Length per Run

Parallel Runs Pump flow splits across runs

Reservoir Volume

Enter 0 if unknown

Total System Volume

—

Pump Flow (Total Output)

Total pump output — divided equally across parallel runs

System Cleaner (Optional)

Mobil Solvancer® in use

Oil-soluble varnish/sludge cleaner — 3–5% treat rate, no post-treatment flush required