Cross-Flow Fan Guide Plate Phasing for Air Separation and Noise Control
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Solution Overview
Problem
Existing air conditioner designs face challenges in sufficiently separating air flows at different positions within the fan due to varying centrifugal speeds, leading to inefficient air separation and potential noise issues from air collisions with guide surfaces.
Innovation Solution
The air conditioner incorporates phase change portions with varying phase difference angles along the rotation axis, where the phase difference angle decreases with proximity to the lower side, ensuring effective separation of air flows by guiding them to appropriate discharge ports and reducing noise through timed collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the outer guide plate and inner guide plate are constituted by plates extending parallel to the rotation axis, then the structure is simple, but the separation between two types of air is insufficient
Solution Approach 1:
The guide plates are designed with different shapes at different locations: the inner guide plate has a first guide surface that is not parallel to the rotation axis to guide upper air, while the outer guide plate has a second guide surface parallel to the rotation axis for lower air. This local differentiation allows each region to be optimized for its specific air flow characteristics, achieving effective separation while maintaining manufacturing feasibility.
Solution Approach 2:
The guide plate system is segmented into multiple functional surfaces: the inner guide plate's first guide surface handles upper air flow, while the outer guide plate's second guide surface handles lower air flow. This segmentation allows independent optimization of each guide surface for its specific air flow path, resolving the contradiction between structural simplicity and separation effectiveness.
2Productivity
If air flows through the fan at different positions in the rotation axis direction, then air is drawn in efficiently, but airs have different centrifugal speeds making separation difficult
Solution Approach 1:
Different guide surfaces are provided for different air flow regions: the first guide surface of the inner guide plate is configured for upper air with lower centrifugal speed, while the second guide surface of the outer guide plate is configured for lower air with higher centrifugal speed. This local quality differentiation allows each guide surface to be optimized for its specific air flow characteristics, achieving effective separation despite speed differences.
Solution Approach 2:
The guide plate configuration changes parameters of the air flow paths: the first guide surface creates a longer, more gradual path for upper air, while the second guide surface creates a shorter, more direct path for lower air. This parameter adjustment compensates for the different centrifugal speeds, allowing both air flows to be effectively separated and guided to appropriate discharge ports.
3Device complexity
If air flows directly to discharge ports without proper guidance, then the structure is simple, but air collisions with guide surfaces generate noise
Solution Approach 1:
The guide surfaces are positioned and configured to preliminarily guide air flows before they reach the discharge ports. The first guide surface preliminarily directs upper air, and the second guide surface preliminarily directs lower air, ensuring that air flows are properly aligned before discharge. This preliminary action prevents sudden air collisions with discharge port edges, reducing noise generation.
4Ease of manufacture
If the guide plates use uniform configuration throughout, then manufacturing is easy, but air flows at different positions cannot be properly separated
Solution Approach 1:
The guide plate system employs local quality differentiation where the inner guide plate has a first guide surface with specific geometry for upper air, and the outer guide plate has a second guide surface with different geometry for lower air. This local customization allows each region to be optimized for its specific air flow characteristics while maintaining overall structural coherence, achieving position-specific separation effectiveness.
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 effectively separates air flows on both the upper and lower sides, reducing noise and improving air conditioning efficiency by aligning air flows with guide surfaces at different timings, thus enhancing the overall performance of the air conditioner.
Implementation Method 1
The fan includes a top plate portion, a bottom plate portion, and a plurality of blade portions located between the top plate portion and the bottom plate portion. The fan is disposed in the ventilation space, and rotates to draw the air in a direction along a rotation axis and to blow out the air in a centrifugal direction around the rotation axis.
Data Source
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AI summary
An inner guide plate is located inside blade portions (10c) of a fan (10) and has an inner guide plate surface (21a) that guides air. An outer guide plate is located outside the blade portions and has an outer guide plate surface (22a) that guides the air guided by the inner guide plate surface toward a discharge port of the fan. In each of predetermined cross sections perpendicular to a rotation axis (CL) of the fan, a reference line (L2) is a line connecting the rotation axis and an outer guide end (22aa) of the outer guide surface that is a radially inner end. In each of the predetermined cross sections, a guide line (L1) is a line connecting the rotation axis and an inner guide end (21aa) of the inner guide surface that is a radially outer end. In each of the predetermined cross sections, a phase difference angle (PA11, PA12, PA21, PA22) is an angle between the guide line and the reference line in a rotation direction (DR1) of the fan. The phase difference angles of the predetermined cross sections are different from each other.