Aircraft Fuel Tank Ventilation With Refrigerative Dehumidification
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Solution Overview
Problem
Aircraft fuel tanks experience significant moisture ingress through their ventilation systems, leading to operational delays, increased maintenance, and microbiological contamination, particularly during descent when warm, humid air enters the tanks.
Innovation Solution
An aircraft fuel tank ventilation system equipped with a refrigerative dehumidifying device featuring a refrigerating element, such as a condensing cold plate, that cools atmospheric air entering the tank, condensing water vapor and removing it through a sump and discharge tube, which can be passively drained using aircraft motion, reducing the need for active pumping and minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a refrigerative dehumidifying device is installed in the ventilation system, then moisture content in fuel tanks is reduced, but device complexity increases
Solution Approach 1:
A refrigerative dehumidifying device is introduced as an intermediary component in the ventilation system between the vent and the fuel tank. This device actively removes moisture from the air entering the fuel tank, preventing water contamination while maintaining system reliability. The device includes a refrigerating element that condenses water vapor from the incoming air stream.
Solution Approach 2:
The refrigerative dehumidifying device changes the temperature parameter of the incoming air stream by cooling it below the dew point. This temperature reduction causes water vapor to condense into liquid water, which is then collected and removed from the system. The device dynamically adjusts cooling parameters to maintain optimal dehumidification during different flight phases.
2Productivity
If active pumping is used to drain condensate, then water removal efficiency is improved, but power consumption increases
Solution Approach 1:
The condensate drainage system is designed to be self-service, utilizing the aircraft's own motion and existing pressure differentials to drain water from the fuel tank. The system employs passive drainage mechanisms such as gravity-driven flow and pressure-equalization cycles that occur naturally during flight maneuvers, eliminating the need for dedicated active pumping during normal operation.
Solution Approach 2:
The system utilizes pneumatic pressure differentials created during aircraft acceleration and deceleration to drive condensate drainage. During certain flight phases, the pressure changes in the fuel tank create natural flow paths that enable water removal without mechanical pumping. The drainage system is designed to harness these dynamic pressure variations for automatic water evacuation.
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 reduces moisture content in fuel tanks, enhancing fuel system reliability, reducing maintenance needs, and minimizing microbiological contamination by efficiently removing moisture from humid air during descent and other flight phases.
Implementation Method 1
cooling the refrigerating element so as to remove water vapour from the air flowing from the vent towards the fuel tank by condensation
Implementation Method 2
The refrigerating element can be connected in a refrigerating cycle to a compressor. The refrigerating cycle may be a single stage vapour compression cycle
Implementation Method 3
The combined effect of gravity and the air flow encourages the water beads to flow towards the bottom of the plate
Data Source
AI summary
An aircraft fuel tank ventilation system, comprising a refrigerative dehumidifying device having a refrigerating element in contact with air flowing between a vent open to the atmosphere and a fuel tank. Also, a method of dehumidifying air introduced into an aircraft fuel tank via the ventilation system, the method comprising directing atmospheric air from the vent into contact with the refrigerating element, and cooling the refrigerating element so as to remove water vapor from the air flowing from the vent towards the fuel tank by condensation.