Turbine Fuel Supply System with Variable Pump and Bypass Valve
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Solution Overview
Problem
Turbine engine fuel supply systems face inefficiencies in managing fuel flow rates across varying speeds, leading to excessive recirculation and thermal rejection, particularly at high speeds and low temperatures, which can cause icing issues.
Innovation Solution
A fluid supply system with a high pressure volumetric pump and a bypass circuit, where a control valve with a variable position obturator is connected to the electronic regulation system to adjust the flow rate based on flight conditions and temperature, minimizing recirculation and thermal rejection by maintaining a constant pressure difference across the metering device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a high pressure fixed capacity volumetric pump is used, then the fuel flow rate is sufficient for the turbine engine across the speed range, but the flow rate exceeds actual needs at high speed causing excessive recirculation and thermal rejection
Solution Approach 1:
The patent applies a variable capacity volumetric pump instead of a fixed capacity pump. The pump capacity is made variable through a adjusting mechanism that can change the displacement volume of the pump based on operating conditions. This allows the pump to deliver the required fuel flow rate at different engine speeds without excessive flow at high speeds, thereby reducing recirculation and thermal rejection while maintaining sufficient fuel supply across the entire speed range.
2Loss of energy
If the flow rate of recirculated fuel is reduced to minimize thermal rejection, then energy loss is reduced, but the ability to prevent fuel icing at low temperatures is compromised
Solution Approach 1:
The patent incorporates a feedback control system that monitors operating conditions (temperature, engine speed, fuel flow rate) and adjusts the pump capacity accordingly. When low temperature conditions are detected, the system increases recirculation flow rate to provide heating and prevent fuel icing. Under normal or high temperature conditions, the system reduces recirculation to minimize thermal rejection and energy loss. This dynamic feedback control allows the system to adapt to varying thermal conditions and prevent fuel icing while optimizing energy efficiency.
3Loss of energy
If a variable capacity volumetric pump is used to adjust flow rate, then recirculation is minimized, but the device complexity increases due to additional adjustment mechanisms
Solution Approach 1:
The patent integrates multiple functions into the variable capacity pump system. The same adjusting mechanism that varies pump capacity also serves as part of the control system for optimizing fuel delivery. The electronic control unit that manages engine operations also controls the pump capacity adjustment, eliminating the need for separate dedicated control systems. This multi-functionality approach reduces overall system complexity while achieving the goal of minimizing recirculation and improving energy efficiency.
4Productivity
If an electric motor drives the volumetric pump with commanded rotation speed, then flow rate can be precisely controlled, but considerable electrical energy is required increasing generator size
Solution Approach 1:
The patent replaces the electric motor drive system with a mechanically driven variable capacity pump system. Instead of using an electric motor with electronically controlled variable speed operation, the system uses a mechanically driven pump with variable displacement capability. This substitution eliminates the need for considerable electrical energy to control pump speed, as the pump capacity is adjusted mechanically through the variable displacement mechanism. The result is reduced electrical energy consumption and smaller generator sizing while maintaining precise flow rate control through mechanical capacity adjustment.
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
This solution effectively reduces thermal rejection and prevents icing by modulating the fuel flow rate in the bypass circuit, ensuring optimal fuel supply and minimizing energy consumption while maintaining efficient engine operation.
Implementation Method 1
a high pressure volumetric pump (4) configured to deliver a flow rate of fuel to said metering device (6)
Implementation Method 2
The control valve (8) is configured to vary the flow rate of fuel in the bypass circuit (14) so as to regulate a pressure difference at terminals of the metering device (6)
Implementation Method 3
The control valve (8) includes a position measurement device (20) for the obturator (82)
Implementation Method 4
The electronic regulation system (3) is configured to command a flow rate of the high pressure pump (4) as a function of an obtained set-point of the position of the obturator (82) by the position measurement device (20)
Implementation Method 5
The bypass circuit (14) is connected to the main circuit (12) by an input (E) situated downstream of the high pressure pump (4) and an output (S) upstream of the high pressure pump (4)
Data Source
AI summary
A fluid supply system (1) for turbine engine, includes a high pressure volumetric pump (4), a fluid metering device (6) and a control valve (8) configured to vary the flow rate of fluid in a bypass circuit (14) so as to regulate the pressure difference between an input and an output of the metering device (6). The control valve (8) includes an obturator, the variable position of which is measured by a sensor (20). An electronic regulation system (3) compares the measured position of the obturator with a position set-point of the obturator determined as a function of a flight condition of the aircraft and/or a measured fluid temperature and corresponding to a fluid flow rate set-point in the bypass circuit (14). The flow rate of the high pressure pump (4) is commanded so that the measured position of the obturator adapts to the position set-point.