Aircraft Fuel Conditioning With Buffer Tank Flow Adaptation
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Solution Overview
Problem
Existing mechanical pumps used for fuel conditioning in turbomachines are inefficient over a wide range of flow rates and pressures, leading to increased stress and reduced efficiency, and cannot optimally adapt to varying fuel requirements in aircraft turbomachines.
Innovation Solution
A fuel conditioning system with a pump operating at a constant speed, a buffer tank, and control valves to dynamically regulate fuel distribution, using an auxiliary power generation device for heating, ensuring efficient fuel supply and storage during varying aircraft phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mechanical pump is used to circulate fuel at varying flow rates, then the fuel flow rate can be adjusted to match aircraft phase requirements, but the pump efficiency decreases and stress increases when operating outside its optimal range
Solution Approach 1:
The fuel supply system is segmented into a primary pump circuit and a secondary buffer tank circuit. The pump operates at constant optimal speed supplying both the turbomachine and the buffer tank, while a control valve regulates the split between them. This segmentation allows the pump to maintain optimal efficiency while the buffer tank provides flow rate adaptation during high-demand phases like takeoff.
2Ease of manufacture
If a mechanical pump operates at constant speed, then the pump design is simpler and more reliable, but the fuel flow rate cannot be dynamically adjusted to match varying aircraft phase requirements
Solution Approach 1:
The buffer tank acts as an intermediary between the constant-speed pump and the turbomachine. The pump delivers fuel at constant flow rate to the buffer tank, and a control valve on the buffer tank outlet dynamically adjusts the flow to the turbomachine based on aircraft phase requirements. This intermediary approach decouples the pump's constant operation from the variable demand of the turbomachine.
3Reliability
If the pump operates at optimal speed for low flow rates, then pump efficiency is maximized, but the fuel flow rate is insufficient during high-demand phases like takeoff
Solution Approach 1:
The buffer tank is pre-filled with fuel during low-demand phases (cruise, landing) when the pump operates at optimal efficiency. This preliminary accumulation of fuel in the buffer tank ensures that when high-demand phases like takeoff occur, the additional flow rate required can be immediately supplied from the buffer tank without compromising pump efficiency.
4Productivity
If the pump operates at high speed to meet peak flow demands, then sufficient fuel flow is provided during takeoff, but the pump experiences increased stress and reduced efficiency
Solution Approach 1:
The system dynamically shifts between pump-driven flow and buffer tank-driven flow based on aircraft phase. During takeoff, the buffer tank outlet valve opens to supplement pump flow, allowing the pump to operate at high speed only when necessary. During cruise and landing, the buffer tank is refilled at optimal pump speeds, creating a dynamic balance that minimizes pump stress while meeting peak demands.
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 efficient fuel conditioning with reduced pump stress and cost, allowing optimal fuel flow adaptation to aircraft phases, particularly during takeoff, using a simple and reliable design.
Implementation Method 1
at least one heat exchanger configured to transfer heat from a hot source to the fuel flow via a heating circuit
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A system (SC) for conditioning fuel configured to supply a main turbomachine (T), based on fuel (Q) from a cryogenic tank (R1), comprising a pump (1) configured to operate at a predetermined constant speed, at least one heat exchanger (3), a supply member (6) for supplying the main turbomachine (T) with a fuel flow (Q), the supply member (6) being configured to deliver a nominal flow rate when the pump (1) is operating at a predetermined constant speed, at least one buffer tank (4), a first valve (V1) for controlling the supply of fuel to the buffer tank (4), a second valve (V2) for controlling the distribution of the fuel flow (Q) and a regulating device (5) that is configured to open the second valve (V2) when the setpoint flow rate is higher than the nominal flow rate.