Flow & Hydraulics
RECIPROCATING COMPRESSOR
Multi-stage cylinder capacity, discharge conditions and power.
- Peng-Robinson equation of state
Reciprocating Compressor evaluates a one- to four-stage reciprocating train on a real-fluid basis — as a design calculation from cylinder geometry, or as a field efficiency test from measured readings.
Capabilities
- Comprehensive Evaluation — from cylinder geometry (bore, stroke, rod diameter, cylinder count), clearances, losses and efficiencies, stage-one suction conditions, discharge target and running speed, solves the full train stage by stage.
- Simplified Efficiency Test — from measured suction and discharge pressures and temperatures at a stage, returns the adiabatic efficiency those readings imply. No geometry or running speed required.
- Per-stage results: compression ratio, volumetric efficiency, displacement, suction volumetric flow, mass flow, isentropic work, discharge temperature, gas power and shaft power.
- Train totals: overall shaft power, overall ratio and standard volumetric flow.
- Optional interstage coolers between stages.
- Built-in and saved cylinder presets to populate geometry.
- Exportable PDF report.
Why the results hold up
Isentropic work is resolved by a constant-entropy flash on the Peng-Robinson fluid, and the actual discharge temperature by an enthalpy match against it. Volumetric efficiency is calculated from clearance volume, pressure ratio and the entered valve and leakage losses, using the real-fluid density ratio across the stage rather than an ideal-gas approximation. Interstage pressures are solved, not entered: an iterative solver keeps the whole train consistent, so every stage passes the same mass flow.
Scope
Steady-state, single operating point. A feed that is liquid or two-phase at the stage-one suction, at a measured stage suction or after an interstage cooler is not calculated. Valve dynamics, pulsation, heat transfer within the cylinders and liquid carry-over are outside the calculation. Discharge temperatures assume adiabatic compression at the entered efficiency; without an interstage cooler, the temperature change across the interstage pressure drop is not modelled.