Combined-wing type axial flow fan blade

Abstract

The invention relates to a combined-wing type axial flow fan blade. A blade wing type is formed by a wing type front section and a thin-plate type trailing edge. The thin-plate type trailing edge canbe cut; the blade is designed regularly according to a non-constant circulation index; and by precisely cutting the thin-plate type trailing edge, the string length, leaf angel and lift coefficient values of the blade at each radius are changed; the lift coefficient value Cy on the cross section of each blade is designed according to an unique rule, a large value the Cy value is taken at the external radium, and a small value of the Cy value is taken at the internal radium, thus realizing maximum satisfaction of demands on pneumatic properties. Due to the structural characteristics of the blade, blade ingredient produced by the same mould can be used for manufacturing axial flow fans of different diameters and different pneumatic properties, thus being not only capable of meeting system demands, but also improving operating efficiency of the fan, realizing energy conservation and emission reduction, and also being capable of decreasing manufacturing cost of the mould to a great extent.

Description

technical field [0001] The invention relates to an axial flow fan blade with a combined airfoil, in particular to an axial flow fan blade whose airfoil is a combination of an airfoil type and a thin plate type, which is used for an axial flow fan for cooling large and medium-sized fiberglass reinforced plastics, and belongs to the field of fluid engineering . technical background [0002] The current axial flow fans in service have the disadvantages of low operating efficiency and serious energy waste. Compared with the current energy-saving and emission-reduction requirements put forward by the country, there is a significant difference. The current conventional solution is to determine the aerodynamic performance parameters of the fan according to the functional requirements of the ventilation system, and then carry out the blade shape design and blade mold manufacturing, but this will greatly increase the mold investment cost of the fan manufacturer, and for small batches...

AI Technical Summary

Problems solved by technology

[0002] The current axial flow fans in service have the disadvantages of low operating efficiency and serious energy waste. Compared with the current national requirements for energy saving and emission reduction, there is a significant difference

The current conventional solution is to determine the aerodynamic performance parameters of the fan according to the functional requirements of the ventilation system, and then carry out the blade shape design and blade mold manufacturing, but this will greatly increase the mold investment cost of the fan manufacturer, and for small batches Due to the high cost of molds for large-diameter low-efficiency fans, it will restrict the enthusiasm of fan factories to open molds, making it impossible to replace many low-efficiency fans with high-efficiency fans

In order to save mold costs, some foreign fan factories often adopt the method of cutting the blade length of the axial flow fan with a similar diameter to produce smaller diameter axial flow fan blades. The blades are manufactured by cutting off the blade length of 265mm or 415mm at the top of the blade or Fan, but the chord length and blade angle often cannot meet the calculation requirements, which will reduce the aerodynamic performance of the fan, and it cuts off the part with high efficiency at the outer diameter of the axial flow fan, making the remaining part relatively low in efficiency, so this is not Optimization

Some foreign fan factories use blades with equal chord length and equal installation angle on fans with different diameters and different aerodynamic performance. Although the mold cost is saved, the efficiency of the fan is not high.

At present, there are also thin-walled hollow blades formed by extrusion technology in China, which can be cut along the sides, but the cutting rules are not completely in accordance with the aerodynamic performance requirements, and the calculation is still lacking in the lift coefficient of the new airfoil at different chord lengths. The relationship curve of the angle of attack, the calculation accuracy is not high, which will lead to low efficiency

Many foreign units simply pursue the use of the same mold to make blades. Due to the wide range of fan diameters, fan impellers with different diameters require different diameters of petioles.

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