Forward-Curved Impeller Extended Tip Reduces Shock Loss
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Solution Overview
Problem
Centrifugal fans with forward-curved blades face performance degradation due to shock loss and separation loss at the suction side of the blades, leading to reduced efficiency and pressure loss, which is not effectively addressed by existing designs.
Innovation Solution
The design incorporates a forward-curved impeller with blades featuring a small inlet angle and a large outlet angle, along with an extended tip portion that minimizes shock and separation losses by allowing gas flow through channels with negligible separation, maintaining performance and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the angle of the blade's leading edge is decreased to decrease entry shock loss and separation loss, then shock loss and separation loss are reduced, but flow deceleration in the blade channel increases causing performance decrease
Solution Approach 1:
The blade design applies different angle characteristics to different portions of the blade: the leading edge has a decreased angle to reduce shock and separation loss, while the extended tip portion has specific geometric features to maintain flow velocity and prevent deceleration. This local differentiation of blade properties resolves the contradiction between reducing losses and maintaining performance.
Solution Approach 2:
The invention extends the blade in the radial direction beyond the traditional trailing edge, creating an extended tip portion. This dimensional extension allows the blade to maintain favorable flow characteristics at the tip region, compensating for the flow deceleration that would normally occur in the blade channel and thus maintaining overall fan performance while benefiting from reduced shock and separation losses.
2Productivity
If forward-curved blades are used to provide low noise level and high air flow, then noise is reduced and air flow increases, but shock loss and separation loss occur at the suction side reducing efficiency
Solution Approach 1:
The blade design applies different angle characteristics to different portions of the blade: the leading edge has a decreased angle to reduce shock and separation loss, while the extended tip portion has specific geometric features to maintain flow velocity and prevent deceleration. This local differentiation of blade properties resolves the contradiction between reducing losses and maintaining performance.
Solution Approach 2:
The invention extends the blade in the radial direction beyond the traditional trailing edge, creating an extended tip portion. This dimensional extension allows the blade to maintain favorable flow characteristics at the tip region, compensating for the flow deceleration that would normally occur in the blade channel and thus maintaining overall fan performance while benefiting from reduced shock and separation losses.
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 design significantly enhances the efficiency and pressure difference of centrifugal fans by reducing shock and separation losses, resulting in improved performance compared to conventional designs without extended tip portions.
Implementation Method 1
the wheel may turn about 90 degrees and accelerate due to centrifugal and Coriolis forces as the gas or air flows over the fan blades
Implementation Method 2
the wheel may turn about 90 degrees and accelerate due to centrifugal and Coriolis forces as the gas or air flows over the fan blades
Data Source
AI summary
A multi-blade forward-curved impeller for a centrifugal fan is disclosed. The impeller may include a blade having a curved portion and an extended portion. The curved portion may have a leading edge and a trailing edge, and the extended portion may extend outward from the trailing edge of the curved portion.