Turbine Compressor Ice Inhibition via Segmented Speed Control
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Solution Overview
Problem
Ice accretion in turbine engine compressors poses a common mode threat to aircraft safety during descent, as low engine thrust and temperature allow ice buildup, leading to potential damage from shed ice, and existing solutions like increasing engine speed or strengthening components have inefficiencies such as increased fuel consumption and weight.
Innovation Solution
A method and control system that operate the turbine engine fan at a predetermined rotational velocity and drive the compressor at an elevated rotational velocity using external power, maintaining the compressor at an elevated temperature to inhibit ice accretion without increasing overall thrust, using a power supply from another engine or an auxiliary power unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine speed is increased to raise the temperature and prevent ice crystal accretion during descent, then ice accretion is inhibited, but the thrust increases beyond what is required for descent, making descent times longer and consuming more fuel
Solution Approach 1:
The invention separates the control of fan speed and compressor speed. The fan is operated at a predetermined rotational velocity (providing minimal thrust), while the compressor is independently driven at an elevated rotational velocity by an external power supply. This segmentation allows the compressor to generate heat to prevent ice accretion without the fan generating excessive thrust that would increase fuel consumption and extend descent time.
Solution Approach 2:
The external power supply (which could be another engine or auxiliary power unit) performs multiple functions: it drives the compressor of the receiving engine to prevent ice accretion, while the fan of the donating engine operates independently to provide necessary thrust. This multi-functionality allows one power source to serve both propulsion and ice prevention purposes.
2Reliability
If the engine speed is increased to prevent ice crystal accretion, then ice accretion is inhibited, but asymmetric thrust occurs between engines and control becomes difficult
Solution Approach 1:
By segmenting the control of fan and compressor speeds, the invention allows independent adjustment of each parameter. The fan speed can be set to provide minimal thrust while the compressor speed is independently elevated to prevent ice accretion. This independent control eliminates the coupling between thrust generation and ice prevention, making engine control during descent much easier and preventing asymmetric thrust issues.
Solution Approach 2:
The control system monitors ice accretion conditions and compressor temperature, adjusting the compressor speed via the external power supply to maintain optimal conditions for ice prevention. This feedback mechanism ensures stable and precise control of the compressor independent of fan speed changes.
3Reliability
If engine components are strengthened to withstand shed ice, then damage from shed ice is prevented, but the engine weight increases and efficiency decreases, increasing fuel consumption
Solution Approach 1:
The invention applies preliminary anti-action by preventing ice accretion in the first place through elevated compressor speed and temperature. By stopping the harmful process (ice buildup) before it occurs, there is no need for defensive measures like strengthening engine components, thereby avoiding the weight penalty associated with reinforced parts.
Solution Approach 2:
The invention converts the potential harm of ice accretion into a benefit by using the external power supply to drive the compressor at elevated speeds, which generates the heat needed to prevent ice buildup. The situation that would normally require heavy reinforcement (ice shedding risk) is transformed into an opportunity to use available power resources to actively prevent the problem.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively prevents ice accretion in turbine engine compressors during descent without increasing thrust or fuel consumption, maintaining a steady aircraft descent rate and avoiding asymmetric thrust between engines, thus eliminating the need for strengthening components to withstand shed ice.
Implementation Method 1
driving the compressor stage of the turbine engine at an elevated rotational velocity which is greater than the nominal rotational velocity of the compressor stage at the predetermined fan rotational velocity so as to inhibit ice accretion within the compressor
Data Source
Figure 1~2
AI summary
A method of inhibiting ice accretion within a turbine engine 4, 6, comprising the steps: (a) operating the turbine engine 4, 6 at a predetermined engine speed; and (b) driving the compressor 8, 10 of the turbine engine 4, 6 at an elevated speed which is greater than the nominal speed of the compressor 8, 10 at the predetermined engine speed so as to inhibit ice accretion within the compressor 8, 10.