Gas Turbine Control System for Thrust Estimation

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Solution Overview

Problem

Current aircraft control systems lack accurate methods for estimating fluid flow parameters in bypass ducts, leading to uncertainties in thrust calculations during flight testing, particularly due to inaccuracies in intake and nozzle coefficients.

Innovation Solution

A control system comprising a primary control parameter leg and a compensation leg, utilizing a processor to generate a modified primary control parameter by measuring and calculating changes in swirl angle and fan pressure distributions within the bypass duct, with instruments arranged in a common measurement plane to derive accurate fluid flow parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional thrust calculation methods using assumed nozzle discharge coefficients are used, then the calculation process is simple, but the measurement precision and reliability of thrust estimation deteriorate due to uncertainties in intake and nozzle coefficients

Engineering Contradiction:
Improvethrust estimation accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control system is divided into separate functional legs: a primary control parameter leg that processes basic engine parameters, and a compensation leg that specifically addresses swirl angle and fan pressure distribution measurements. This segmentation allows each leg to be optimized independently, with the compensation leg adding precision without requiring complete redesign of the primary control system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary compensation mechanism that measures swirl angle and fan pressure distribution to correct deficiencies in the primary thrust calculation method. This intermediary system acts as a mediator between the simple primary control and the complex reality of fluid flow variations, providing corrected control parameters without requiring complete system replacement.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If instruments are arranged in a common measurement plane to measure swirl angle and fan pressure distribution, then the measurement precision of fluid flow parameters improves, but the device complexity and instrumentation requirements increase

Engineering Contradiction:
Improvefluid flow parameter accuracyVSAvoidinstrumentation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Multiple measurement functions (swirl angle measurement and fan pressure distribution measurement) are merged into a single common measurement plane. This consolidation allows simultaneous acquisition of multiple fluid flow parameters at one location, reducing the overall number of measurement stations required while improving measurement precision through coordinated multi-parameter detection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The common measurement plane serves multiple functions: it measures swirl angle, measures fan pressure distribution, and provides data for both primary control parameter calculation and compensation leg processing. This multi-functional design maximizes the utility of the instrumentation while minimizing redundant measurement systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3584428B1Control system for a gas turbine engine
Publication Date: 2021.03.31 ROLLS ROYCE PLC
  • EP3584428B1 patent drawingFigure 1
  • EP3584428B1 patent drawingFigure 2~3
  • EP3584428B1 patent drawingFigure 4~5

AI summary

A control system (100) operable to provide a modified primary control parameter for an aircraft, the control system (100) comprising: a primary control parameter leg configured to output a demand in a primary control parameter (103) of the aircraft; a primary control parameter compensation leg configured to receive a detected change (107) in absolute levels and/or spatial distributions of swirl angle and/or fan pressure at a primary control parameter relative to a reference and convert the detected change (107) into a change to the primary control parameter (106); and a processor adapted to: receive the demand in the primary control parameter (103) output from the primary control parameter leg and the change to the primary control parameter (106) output from the primary control parameter compensation leg; compare the demand in the primary control parameter (103) output from the primary control parameter leg and the change to the primary control parameter (106) output from the primary control parameter compensation leg; and generate a modified primary control parameter (105) for the aircraft.