Rotodynamic Pump Variable Impeller Clearance Pressure Regulation
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Solution Overview
Problem
Prior art aircraft engine fuel pumps face performance issues under depressed inlet conditions due to fuel recirculation, which affects their operational efficiency.
Innovation Solution
A rotodynamic pump design featuring a pressure regulating mechanism that adjusts the clearance between the impeller and the housing to regulate fluid delivery pressure, using a movable housing portion and a pressure sensor-controlled actuator to maintain a setpoint pressure, either passively through a bellows and spring mechanism or actively with a PID control algorithm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If fuel recirculation is used to regulate delivery pressure, then pressure regulation is achieved, but pump operational performance deteriorates under depressed inlet conditions
Solution Approach 1:
The patent applies the dynamics principle by making the impeller clearance variable rather than fixed. The pressure regulating mechanism dynamically adjusts the clearance between the impeller and pump housing based on operating conditions, allowing the pump to maintain optimal performance across different inlet conditions while regulating delivery pressure, thereby eliminating the need for fuel recirculation
Solution Approach 2:
The patent changes the physical parameter of impeller clearance from a fixed value to a variable parameter that can be adjusted in real-time. By varying the clearance parameter in response to inlet conditions and delivery pressure requirements, the pump achieves both pressure regulation and maintained operational performance without the harmful effects of recirculation
2Device complexity
If fixed impeller clearance is used, then pump structure is simple, but delivery pressure cannot be regulated effectively under varying conditions
Solution Approach 1:
The patent transforms the static impeller clearance into a dynamic, adjustable parameter through the pressure regulating mechanism. This allows the pump structure to adapt to varying operating conditions and regulate delivery pressure effectively, while the mechanism integrates smoothly into the existing pump architecture to minimize added complexity
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 solution enhances the pump's operational efficiency by dynamically adjusting clearance to maintain optimal delivery pressure, improving performance under varying conditions and ensuring consistent fuel supply to the aircraft engine.
Implementation Method 1
a bellows and a spring disposed between the movable housing portion and the pump body
Implementation Method 2
a bellows and a spring disposed between the movable housing portion and the pump body
Implementation Method 3
The actuator includes at least one of an electric motor, and a hydraulic actuator
Implementation Method 4
The impeller is rotatable about a rotation axis to pump the fluid from the inlet to the outlet
Data Source
AI summary
A rotodynamic pump for pumping a fluid includes an impeller, a housing surrounding the impeller, and a pressure regulating mechanism. The pressure regulating mechanism is configured to adjust the clearance between the impeller and the impeller housing to regulate pressure of the fluid downstream of the impeller. A method of regulating the delivery pressure is also disclosed.