🔄 Rotary Twin-Screw Compressor Sizer

Size industrial rotary twin-screw compressors: built-in volume ratio Vi matching, over/under-compression losses, oil injection cooling, and shaft power demand.

⚡ Fortran 90 Engine Double Precision (IEEE 754) ✓ ISO / ASME Validated

Turbomachinery

📊 Solver Telemetry ● ACTIVE

👁️ Views 31

⚡ Solves 24

💾 Downloads 446 📦 Fortran Code 5.2 KB

📅 Released Jun 2026

⏱️ Latency < 1 ms

🔄 Intermeshing Male/Female Helical Screw Rotors & Oil Spray

Real-time visual simulation: Suction pocket trapping, continuous screw meshing compression, and oil cooling

📝 Configuration & Presets

💨 Industrial Air (8.5 bar) ❄️ Ammonia Cold Booster 🔥 Biogas 16 bar Injection 🌿 Propane R290 Chiller

💨 Gas Medium & Suction

Gas Medium:

Suction Pressure P₁ [bar a]:

Suction Temp T₁ [°C]:

🎯 Displacement & Discharge

Discharge Pressure P₂ [bar a]:

Swept Volume V_disp [m³/h]:

⚙️ Built-in V_i & Oil Cooling

Built-in Volume Ratio V_i:

Injected Oil Flow [L/min]:

Twin-Screw Compressor Formulation:
• Built-in Pressure Ratio: Π_i = V_i^k
• Indicator Work: W_ind = [k/(k−1)]·P₁·V₁·[V_i^k−1−1] + (P₂−Π_i·P₁)·(V₁/V_i) [kW]
• Shaft Power: P_shaft = W_ind / 0.92 [kW]
• Oil Cooling: controls discharge temperature to ~75–90°C.

📊 Performance Results

📊 Output Summary
💾 Fortran Source

Compressor Shaft Power Demand

64.0 kW

Adiabatic Eff: 86.0% | Volumetric: 89.2%

UNDER-COMPRESSION (P2 > Pi·P1)

Oil-Cooled Discharge Temp 50.0 °C Without oil: 67 °C

Built-in Internal Ratio (Π_i) 3.50 Actual PR = 4.00

Gas Mass Flow Rate 0.298 kg/s 1073.2 kg/h

Oil Cooling Heat Load 52.5 kWth 75 L/min oil circulation

📈 Shaft Power Demand P (kW) vs Discharge Pressure P2 (bar)

📊 Adiabatic Efficiency ηad (%) vs Built-in Volume Ratio Vi

=================================================================
 THERMOFLUIDCALC — ROTARY TWIN-SCREW COMPRESSOR REPORT
=================================================================
Case Title                 : Ammonia Low-Temperature Cold Storage Booster Screw
Process Gas Medium         : Ammonia Refrigerant NH3 R717 (k=1.31, MW=17.03)
Operating Pressures        : P1 = 1.20 bar a, P2 = 4.80 bar a (PR = 4.00)
Screw Volume Geometry      : Vi = 2.60 (Pi = 3.50), Vdisp = 1200.0 m3/h, N = 2950 rpm
-----------------------------------------------------------------
SHAFT POWER CONSUMPTION    : 64.01 kW
Adiabatic / Volumetric Eff.: 86.00% / 89.20%
Compression Matching Regime: UNDER-COMPRESSION (P2 > Pi·P1)
Discharge Gas Temperature  : 50.0 C (Oil Cooled) / 67.2 C (Dry)
Gas Flow Delivered         : 0.298 kg/s (1073.2 kg/h)
Oil Cooling Duty           : 52.5 kWth (at 75.0 L/min)
=================================================================

📘 Calculation Methodology & Screw Compressor Standards

Built-in Volume Ratio ($V_i$) & Indicator Losses

Twin screw compressors have a fixed internal volume ratio $V_i$. If the system pressure ratio differs from $V_i^k$, thermodynamic over-compression or under-compression indicator losses occur upon discharge port opening.

Oil Injection & Temperature Control

Oil flooded into the compression pocket seals rotor clearances and absorbs over 80% of the compression work, keeping discharge gas temperatures well below $100^\circ\text{C}$.

Key Engineering Assumptions

ISO 1217 positive displacement compressor standards.
API 619 oil-injected rotary screw compressor design.
Widely used in industrial plant air systems, ammonia cold storage, and biogas boosting.

ThermoFluidCalc Engineering Report