Aircraft Air-Duct Cooling Using Liquid Nitrogen Backup Injection
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Solution Overview
Problem
Current aircraft cooling systems face challenges in efficiently managing transient conditions and variable operating parameters, particularly when ambient temperatures exceed design limits, leading to insufficient cooling and excessive power consumption.
Innovation Solution
A modular cooling system that integrates a main evaporative or air cycle cooling system with a supplementary liquid nitrogen injection system, allowing for on-demand cooling by evaporating nitrogen in air ducts to enhance temperature reduction, which is easily retrofittable and adaptable to varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the main cooling system is designed to handle maximum heat load over complete flight envelope, then cooling capability is improved, but power consumption and system complexity increase excessively
Solution Approach 1:
The cooling system is divided into two independent segments: a main cooling system for normal operating conditions and a supplementary cooling system using liquid nitrogen for extreme conditions. This segmentation allows each subsystem to operate only when needed, avoiding the excessive power consumption of a single oversized system running continuously.
Solution Approach 2:
The supplementary cooling system changes the thermal parameter of the air by injecting liquid nitrogen that evaporates and absorbs heat, providing additional cooling capacity without requiring the main system to operate at maximum capacity during normal conditions.
2Device complexity
If the main cooling system is designed for reference mission profile, then system simplicity is improved, but adaptability to variable operating parameters deteriorates
Solution Approach 1:
The supplementary cooling system with liquid nitrogen reservoir and injection ports provides multi-functionality, enabling the cooling system to handle both normal operating conditions (main system only) and extreme conditions (main system plus supplementary system), thus improving adaptability without requiring a complete redesign for each scenario.
3Temperature
If ambient air temperature rises to 71°C, then heat dissipation to ambient air becomes difficult, but the cooling system must still maintain adequate cooling
Solution Approach 1:
The high ambient temperature scenario is converted into a manageable condition by using liquid nitrogen's extreme cold temperature (-196°C) as a counterbalancing thermal resource. The evaporation of liquid nitrogen absorbs excessive heat from both the electronic devices and the warm ambient air, effectively converting the thermal challenge into a controllable cooling process.
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
The system provides flexible and efficient cooling, maintaining optimal temperatures for electronic and mechanical components while minimizing power consumption, even under extreme ambient conditions, and can be easily integrated into existing vehicles.
Implementation Method 1
The reservoir for liquid nitrogen is coupled with the injection port of the at least one air duct via the valve for injecting and evaporating nitrogen in the at least one air duct on demand.
Implementation Method 2
The main cooling system is an evaporative cooling system which comprises at least one heat exchanger arranged in the air inlet or an air cycle cooling system.
Data Source
Figure 1~2
AI summary
A cooling system (2) for an interior space of a vehicle comprises a main cooling system (4) coupled with an air inlet (6) for receiving air (10) and coupled with the interior space (12, 14, 16, 18, 20) for providing cooled air to the interior space (12, 14, 16, 18, 20), at least one air (8, 22, 24, 26) duct arranged between the air inlet (6) and the interior space (12, 14, 16, 18, 20), a reservoir (30) for liquid nitrogen having a nitrogen outlet (34) and a valve (36) arranged between the outlet (34) and an injection port (38) of the at least one air duct (8, 22, 24, 26). The reservoir (30) is couplable with the injection port (38) of the at least one air duct (8, 22, 24, 26) via the valve (36) on demand for evaporating nitrogen in the at least one air duct (8, 22, 24, 26). With the injection of liquid nitrogen the main cooling system (4) is supported in case it is not able to provide a sufficient cooling power.