Jet Fan With Coanda Surfaces for Pressure Differential Airflow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bladeless fans struggle to efficiently convey air flows between environments at different pressure levels, leading to inefficiencies and safety concerns in aircraft applications, where noise, vibration, and reliability are critical issues.
Innovation Solution
The design incorporates an additional annular conveying duct with Coanda surfaces and a nozzle to enhance air flow amplification and pressure handling, reducing turbulence and noise while allowing operation between distinct pressure environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional bladeless fan with a single conveying duct is used, then the structure is simple and easy to manufacture, but the fan cannot efficiently convey air flows between environments at different pressure levels
Solution Approach 1:
The conveying duct is divided into two separate ducts: a first conveying duct for primary flow and a second conveying duct for secondary flow. This segmentation allows each duct to be optimized for its specific function and enables the system to handle different pressure environments effectively, resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The second conveying duct is positioned inside the first conveying duct, creating a nested configuration. This nesting arrangement allows both ducts to coexist in a compact space, providing the ability to operate between different pressure environments while minimizing the increase in overall device complexity.
2Reliability
If traditional fans are used in aircraft applications, then the fan structure is simple, but the reliability is reduced due to high-speed fragments and overheating risks
Solution Approach 1:
The invention extracts the harmful effects by separating the primary and secondary flows into different ducts, preventing mixing of flows that could cause instability. This extraction approach improves reliability by eliminating the risks associated with traditional fans (fragments and overheating) while maintaining a manageable structural complexity.
Solution Approach 2:
The dual duct configuration acts as an intermediary system that mediates between the primary flow source and the secondary flow environment. This intermediary structure improves reliability by controlling flow separation and preventing direct interaction between flows that could lead to instability and failure.
3Reliability
If jet pumps are used instead of traditional fans, then the reliability is improved, but the noise level increases and efficiency becomes sub-optimal
Solution Approach 1:
The invention changes the flow parameters by creating distinct primary and secondary flow paths with different pressure characteristics. This parameter optimization allows the fan to operate reliably like a jet pump while reducing noise by improving flow efficiency and reducing turbulence in the conveying ducts.
4Productivity
If the primary air flow is optimized upstream of the outlet mouth, then the efficiency and silence are improved, but the device complexity increases
Solution Approach 1:
The invention applies local quality optimization by creating specific geometric features (such as the annular mouth with tapered shape and Coanda surface) at critical locations within the conveying ducts. These localized geometric optimizations improve flow efficiency and reduce noise without requiring complex modifications throughout the entire duct system.
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 configuration increases the fan's operational head, reduces noise and vibration, enhances reliability, and improves efficiency, making it suitable for aircraft applications by effectively managing air flows between different pressure environments.
Implementation Method 1
The Coanda surface is arranged so that the primary air flow coming out of the annular mouth is directed onto said Coanda surface. The primary air flow generates a depression at the suction section of the fan, amplified by the Coanda effect and generating a secondary air flow
Implementation Method 2
the need to raise the head of the fan described above is felt in the sector, in order to enable it to convey the primary and secondary flows between two distinct environments at respective different pressure levels
Data Source
AI summary
A fan is described with a first conveying element, fluidly connectable with a source of a primary air flow and defining a first passage for the primary air flow; a first mouth receiving a first aliquot of the primary air flow from the first passage; a first Coanda surface onto which the first mouth directs the first aliquot; and a first opening fluidly connected with the first mouth and crossable by the first aliquot coming of the first mouth and a secondary air flow; the fan comprises a second conveying element, fluidly connected with the first conveying element and defining internally a second passage for a second aliquot of the primary air flow, and comprises: a second mouth receiving the second aliquot from the second passage and a second Coanda surface onto which the second mouth directs the second aliquot.