Neqsim Gas Turbine Performance Screening

Gas Turbine Performance Screening

Use this skill for public, educational gas-turbine performance screening. It corrects an ISO base rating for ambient temperature, site elevation, and inlet/exhaust pressure losses to estimate site-rated shaft power, site heat rate, thermal efficiency, fuel heat input, exhaust mass flow, and exhaust temperature so an agent can scope a driver-selection study before detailed package review.

When to Use

• When a user asks how much power a gas-turbine driver makes at site conditions versus its ISO rating.
• When an agent needs a quick site heat rate, fuel heat input, or exhaust mass flow estimate for waste-heat or HRSG scoping.
• When examples must run without confidential vendor performance maps or company package specs.

Inputs

• iso_base_power_kw: ISO base-load shaft power rating in kW.
• iso_heat_rate_kj_kwh: ISO base-load heat rate in kJ/kWh.
• ambient_temperature_k: site ambient temperature in kelvin, default 288.15 (ISO reference).
• site_elevation_m: site elevation above sea level in m, default 0.
• relative_humidity: site relative humidity fraction, default 0.6 (small effect).
• inlet_pressure_loss_mbar: inlet system pressure loss in mbar, default 10.
• exhaust_pressure_loss_mbar: exhaust system pressure loss in mbar, default 10.
• required_shaft_power_kw: optional driven-equipment shaft power in kW for the margin check.

Outputs

• site_power_kw: derated site shaft power.
• ambient_derate_factor: ambient-temperature power factor.
• altitude_derate_factor: site-elevation power factor.
• pressure_loss_derate_factor: combined inlet/exhaust pressure-loss power factor.
• total_derate_factor: product of all derate factors.
• site_heat_rate_kj_kwh: site heat rate after efficiency degradation.
• thermal_efficiency: shaft thermal efficiency from the site heat rate.
• fuel_heat_input_kw: fuel lower-heating-value heat input.
• exhaust_mass_flow_kg_s: screening exhaust mass flow.
• exhaust_temperature_k: screening exhaust temperature.
• power_margin_ratio: site power divided by required shaft power, or null.
• power_warning: ok, watch, insufficient-power, or no-rating.
• assumptions: public assumptions used by the placeholder model.

Engineering Method

The Python class GasTurbinePerformanceModel uses open performance-derate relations only:

• ambient derate uses f_amb = 1 - 0.007 (T_amb - 288.15), clamped at zero.
• altitude derate uses f_alt = 1 - 1.1e-4 * elevation, from reduced barometric pressure.
• pressure-loss derate uses f_inlet = 1 - 0.002 * dP_inlet and f_exhaust = 1 - 0.001 * dP_exhaust.
• site power uses P_site = P_iso * f_amb * f_alt * f_inlet * f_exhaust * f_humidity.
• site heat rate uses HR_site = HR_iso (1 + 0.5 (1 - f_total)) so efficiency falls with derate.
• fuel heat input uses Q_fuel = P_site * HR_site / 3600.
• exhaust mass flow uses a fixed specific-flow factor m_exh = P_site * 0.003.

This is educational and screening-only logic. It assumes linear derates, a fixed specific exhaust flow, and a typical exhaust temperature. It is not a replacement for validated gas-turbine performance models or qualified package review.

Python Usage Pattern

from gas_turbine_performance_screening import GasTurbinePerformanceModel

model = GasTurbinePerformanceModel()
result = model.evaluate(
    iso_base_power_kw=30000.0,
    iso_heat_rate_kj_kwh=9500.0,
    ambient_temperature_k=303.15,
    site_elevation_m=50.0,
    required_shaft_power_kw=26000.0,
)

print(result.site_power_kw)
print(result.site_heat_rate_kj_kwh)
print(result.power_warning)

Related NeqSim Functionality

For validated power-generation calculations, redirect to NeqSim classes:

• neqsim.process.equipment.powergeneration.GasTurbine — gas-turbine driver model with fuel and exhaust calculations.
• neqsim.process.equipment.powergeneration.HRSG — heat-recovery steam generator using turbine exhaust.
• neqsim.process.equipment.powergeneration.CombinedCycleSystem — combined-cycle integration of turbine and steam systems.

This skill is a public triage layer that decides when to invoke a validated gas-turbine model.

Validation Checklist

• ISO base power and heat rate are positive.
• Ambient temperature is positive and elevation is non-negative.
• Tests cover ambient derate, the power margin, the fuel/efficiency estimate, and invalid input.
• Results are described as educational screening indicators.
• Real driver selection is redirected to validated NeqSim power-generation classes and qualified review.

Common Mistakes

Limitations

• No proprietary vendor performance maps, fuel composition effects, or company specs are included.
• Derates are linear screening factors; part-load, water injection, and DLE effects are not modelled.
• Exhaust mass flow and temperature use fixed screening assumptions, not a heat-and-mass balance.

References

• ISO 3977, Gas turbines — Procurement.
• ISO 2314, Gas turbines — Acceptance tests.
• NeqSim repository: https://github.com/equinor/neqsim