What Is the Combustor Pattern Factor & Hot Spot Calculator?
The pattern factor (PF) measures the severity of combustor exit temperature peaks relative to the average combustor temperature rise.
It directly governs the creep life and cooling air requirements of first-stage high-pressure turbine stators.
How Does the Combustor Pattern Factor & Hot Spot Calculator Work?
Air dilution holes in the combustor liner mix cooler air into the core combustion gases to smooth out hot streaks.
A low pattern factor signifies superior mixing, protecting stationary guide vanes from thermal oxidation.
Combustor Pattern Factor & Hot Spot Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Standard gas turbine combustor pattern factor definition.
How to Use the Combustor Pattern Factor & Hot Spot Calculator
- Input peak measured hotspot temperature, average exit temperature, and inlet temperature.
- Review pattern factor and turbine blade thermal safety classification.
Step-by-Step Example Calculation
Aeroderivative Gas Turbine Combustor
Input Values:
Understanding Your Result
Modern aviation combustors aim for PF ≤ 0.20 to 0.25.
Heavy-duty industrial gas turbines require PF ≤ 0.12 to 0.18 for 30,000-hour base-load blade life.
Factors That Affect the Result
- Liner dilution hole sizing, fuel nozzle atomization uniformity, and swirler aerodynamics.
When Should You Use This Calculator?
- Combustor rig testing, gas turbine development, and turbine blade thermal stress analysis.
Assumptions & Limitations
- Calculates overall pattern factor; radial profile factor (profile factor) is evaluated separately.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard aero-propulsion design equation.