Oblique-Head Lubrication Nozzle for Turbomachine Coupling Startup
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Solution Overview
Problem
Conventional lubrication nozzles for aircraft turbomachine couplings, such as bevel gears, fail to effectively lubricate during startup phases when fluid ejection speed is low, as the lubricant tends to flow vertically due to inertial forces, missing the target zones.
Innovation Solution
A lubrication device with an ejection head featuring an oblique end face and unhooking edge, which directs lubricating fluid towards the stall ridge, ensuring effective lubrication both at high and low ejection speeds by orienting the ejection orifice along an inertial direction and using a guide mechanism to prevent fluid from flowing outside the target zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the ejection orifice is oriented perpendicular to the longitudinal axis for high-speed ejection, then the lubricating fluid can reach the target zone at high ejection speeds, but the fluid flows vertically due to gravity and misses the target zone at low ejection speeds
Solution Approach 1:
The end face of the ejection head is designed to be oblique relative to the longitudinal axis, creating a dynamic adaptation mechanism. This oblique orientation allows the nozzle to automatically adjust the fluid flow direction based on ejection speed: at high speeds, the jet follows the ejection direction; at low speeds, gravity causes the fluid to flow along the oblique end face toward the unhooking edge, ensuring reliable lubrication across varying operational conditions
Solution Approach 2:
The geometric parameters of the ejection head are optimized, specifically the oblique angle of the end face and the position of the unhooking edge. These parameter changes enable the system to maintain effective lubrication by altering the flow path characteristics according to the ejection speed regime, transitioning from direct jet impingement at high speeds to gravity-assisted flow along the oblique surface at low speeds
2Reliability
If the end face is oriented oblique to the longitudinal axis to guide fluid at low speeds, then the fluid can reach the target zone during startup, but the jet direction may be misaligned at high ejection speeds
Solution Approach 1:
The oblique end face acts as an intermediary surface that mediates between the ejection orifice and the target zone. At low ejection speeds, this intermediary surface guides the fluid flow under gravity toward the unhooking edge and target zone. At high ejection speeds, the fluid jet passes through or alongside this intermediary structure, maintaining alignment with the ejection direction while the oblique face continues to provide flow guidance for any fluid that contacts it
3Reliability
If the ejection head is positioned vertically above the coupling to lubricate during startup, then the fluid flows vertically with gravity, but this positioning may not optimize high-speed ejection performance
Solution Approach 1:
The ejection head design achieves multi-functionality by combining the oblique end face with the unhooking edge feature. This configuration allows the same nozzle structure to effectively lubricate the coupling during both startup phases (low ejection speed) and normal operation phases (high ejection speed), eliminating the need for different nozzle configurations for different operational conditions
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 device ensures precise and controlled lubrication of turbomachine couplings by directing lubricant jets to target zones at both high and low ejection speeds, enhancing lubrication efficiency across various operational phases.
Implementation Method 1
the fluid leaving the nozzle is mainly subjected to an inertial force such as gravity and thus tends to flow vertically or more generally in an inertial direction corresponding to said inertial force
Implementation Method 2
the ejection orifice defining a ejection direction and opening onto an end face of the ejection head, the end face being oriented with respect to the longitudinal axis of the ejection head so as to guide the lubricating fluid to flow towards the circumferential face up to a stall ridge
Data Source
Figure 1~2
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Figure 6~8
AI summary
The invention relates to a nozzle (3) for lubricating a coupling (21), such as a conical coupling of a turbomachine accessory drive system. This nozzle (3) comprises a body having an ejection head (32). The body includes a main channel adapted to convey a lubricating fluid to the ejection head (32). The ejection head (32), extending along a longitudinal axis (A1), has an ejection orifice arranged to eject the lubricating fluid from the main channel (311). This ejection orifice (321) opens onto an end face (33) of the ejection head (32).According to the invention, this end face (33) is oblique with respect to the longitudinal axis (A1) of the ejection head (32) and with respect to an inertial direction along which an inertial force (P1) is applied acting on the lubricating fluid, the end face (33) being configured to convey the lubricating fluid flowing over it under the action of the inertial force (P1) to a stall edge (331) partially delimiting the end face (33).