Bidirectional Fan Blade Design for Even Airflow in Reversing Dryers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Clothes dryers face inefficiencies in air circulation and energy usage due to uneven air volume and pressure, leading to prolonged drying times and potential safety hazards from local overheating of the heating device.
Innovation Solution
A positive-negative-rotation fan design featuring a combination of whole-size and half-size fan blades arranged alternately on the periphery, along with a symmetrical volute and flow guide device, ensures continuous and even wind circulation with increased flow pressure, reducing turbulence and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drum rotates in clockwise and counterclockwise directions alternately, then the clothes can be turned over effectively for even drying, but the air volume and air pressure become uneven and low
Solution Approach 1:
The fan blade is divided into multiple independent blade elements arranged radially, with each blade element having an optimized cross-sectional shape. This segmentation allows the fan to maintain balanced aerodynamic performance during bidirectional rotation, ensuring even air distribution and stable pressure while effectively turning over clothes for uniform drying.
Solution Approach 2:
The fan blade employs asymmetric cross-sectional geometry where the pressure surface and suction surface have different curvatures and thickness distributions. This asymmetric design creates consistent airflow patterns regardless of rotation direction, maintaining stable air volume and pressure while enabling effective clothes turnover for even drying.
2Device complexity
If the main flow of airflow always flows along the side wall to the heating device, then the heating device can be simple in structure, but severe back-flows occur leading to low heating efficiency and local overheating
Solution Approach 1:
A flow guide device with guide blades is introduced as an intermediary component between the fan and heating device. The guide blades redirect the airflow at optimal angles, eliminating severe back-flows and ensuring uniform air distribution across the heating device surface. This maintains heating efficiency while keeping the heating device structure simple.
Solution Approach 2:
The flow guide device creates periodic airflow patterns through its blade arrangement, which systematically directs air flow along the heating device surface. This periodic action prevents localized stagnation and back-flows, ensuring uniform heat distribution and preventing local overheating while maintaining simple heating device structure.
3Object-affected harmful factors
If temperature protection control is implemented by cutting off power supply when temperature exceeds preset value, then safety hazard is avoided, but drying efficiency is reduced and service life of electrical components is affected
Solution Approach 1:
The flow guide device rapidly directs airflow across the heating device surface, causing the air to 'skip' over potential hot spots before they can develop into dangerous local overheating. This continuous high-velocity flow prevents temperature buildup, eliminating the need for protective shutdowns while maintaining high drying efficiency.
Solution Approach 2:
The flow guide device pre-distributes airflow uniformly across the heating device surface before the air contacts the heating elements. This preliminary uniform distribution prevents localized overheating from occurring in the first place, eliminating safety hazards without requiring power cutoffs and maintaining continuous high drying efficiency.
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 enhances drying efficiency, reduces energy consumption, and eliminates safety hazards by maintaining consistent air flow and pressure, ensuring even drying and extending the service life of electrical components.
Implementation Method 1
maintain a continuous wind circulation with even air volume and great flow pressure... reducing turbulence
Data Source
AI summary
A positive-negative-rotation fan for a clothes dryer comprises multiple whole-size fan blades arranged on a periphery of an outer frame of the fan, and multiple half-size fan blades arranged on the periphery of the outer frame of the fan. The half-size fan blades and the whole-size fan blades have similar shapes, and the size of an edge of each half-size fan blade parallel to a radial direction of the fan is half of the size of a corresponding edge of the whole-size fan blade. The clothes dryer using the positive-negative-rotation fan can provide an even and great air volume and a great air intake pressure in a clockwise and counterclockwise alternating rotation process, and accordingly clothes are evenly dried and the drying time is short. By using a flow guide device, aggregated back-flows are not generated between the fan and an outlet of a volute.