Aircraft Refrigerant Cooling With Internal Freeze-Prevention Heating
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Solution Overview
Problem
Existing aircraft refrigerant cooling systems face issues with refrigerant freezing or solidification during prolonged exposure to low temperatures or low flow rates, leading to disrupted cooling of turbomachine components, and existing solutions like finned heat exchangers compromise aerodynamic performance.
Innovation Solution
A refrigerant cooling system with internal safety heating devices that activate when temperature thresholds are met, directly heating the refrigerant within circulation channels to prevent freezing, using either heat transfer pipes or resistive electrical cables, without compromising aerodynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a finned heat exchanger is used to provide a bypass channel for heating frozen channels, then the refrigerant can circulate to heat frozen channels by conduction, but the fins form asperities on the nacelle surface that disturb the outside air stream and reduce aerodynamic performance
Solution Approach 1:
The invention extracts the heating function from the external finned structure and relocates it internally within the circulation channels. The heating element is placed inside the channels where it directly contacts the refrigerant, eliminating the need for external fins that disturb airflow while maintaining the ability to heat frozen channels.
Solution Approach 2:
The heating element is nested within the circulation channels, with the heating device positioned inside the same space where refrigerant flows. This nested arrangement allows the heating function to be integrated without adding external structures that would affect aerodynamics.
2Temperature
If the refrigerant flow rate is too low or exposure to low temperatures is prolonged, then the refrigerant is likely to freeze in the channels, but freezing slows down or prevents refrigerant circulation and disrupts cooling of hot zones
Solution Approach 1:
The heating device activates preemptively when temperature thresholds are approached or flow rate decreases, preventing freezing before it occurs. By detecting low flow rates or temperatures in advance, the system applies heating action before the harmful freezing state develops, maintaining reliable operation.
Solution Approach 2:
The system uses sensors to monitor refrigerant temperature and flow rate, providing feedback to the control device. When the feedback indicates low flow rate or temperature approaching freezing points, the control device activates the heating element to counteract the trend and maintain reliable refrigerant circulation.
3Reliability
If an auxiliary heating channel is mounted next to each channel to efficiently heat all channels, then all channels can be heated effectively, but the system becomes expensive and bulky
Solution Approach 1:
A single heating element is designed to serve multiple circulation channels simultaneously. The heating device extends across several channels or is positioned to heat multiple channels through thermal conduction, providing universal heating coverage without requiring separate heating elements for each channel, thus reducing complexity and cost.
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
Maintains refrigerant circulation and cooling efficiency during low-temperature conditions, ensuring turbomachine component cooling without aerodynamic penalties.
Implementation Method 1
A refrigerant cooling system with internal safety heating devices that activate when temperature thresholds are met, directly heating the refrigerant within circulation channels to prevent freezing
Implementation Method 2
the circulation channels being configured to be at least partially in contact with an air flow so as to cool the refrigerant fluid by convection
Data Source
Figure 1~2
Figure 3~4B
Figure 5A
AI summary
A system (1) for cooling a refrigerant (R) for an aircraft comprising a plurality of ducts (2) for circulating the refrigerant (R) that are configured to be at least partially in contact with an airflow (A) so as to cool the refrigerant (R) through convection, the cooling system (1) comprising a safety heating device (3) extending internally inside at least one portion of the circulation ducts (2) so as to heat the refrigerant (R), a member (4) for measuring a physical parameter of the refrigerant (R) according to the flow rate of the refrigerant (R) in the circulation ducts (2) and a control member (5) configured to activate the safety heating device (3) when the measured physical parameter is below a predetermined threshold corresponding to a minimum flow rate of the refrigerant (R) in the circulation ducts (2).