Fan assembly and method

Abstract

The axial fan assembly according to some embodiments of the present invention has a shroud, a motor coupled to the shroud, and a fan coupled to the motor. By employing selected vane-to-blade ratios, blade twist angles, blade pitch angles, blade-to-shroud axial gaps, shroud solidities, vane swept angles, and vane inlet and outlet angles of specified amounts or falling within specified ranges, desirable fan performance is achieved. Any one or more of these parameters can be utilized alone or in combination with other parameters as desired.

Description

BACKGROUND OF THE INVENTION [0001] Fans are used to generate air movement in a wide variety of applications, such as in heating, ventilating, and cooling systems. For example, a variety of axial-type fans (i.e., fans in which fluid is moved in a direction along the axis of rotation of the fan) are used in many industrial applications such as for ventilation purposes in office buildings, greenhouses, barns, factories, and other structures. Axial ventilation fans also have residential uses, such as in kitchens and bathrooms. As previously mentioned, axial fans are also commonly used in heating and cooling systems for heat transfer purposes. For example, axial fans are used for heat transfer purposes in a variety of applications, such as in air conditioning units, refrigeration units, computers, and in cars and other vehicles. In most of these applications, the fan is used to move air across a heat exchanger, wherein heat is transferred to the air as it passes by and / or through the hea...

AI Technical Summary

Problems solved by technology

Inefficient fans consume more power, and are therefore less desirable than more efficient fans.

Also, inefficient fans tend to require a different rotor geometry than efficient fans in order to meet the ventilation and heat transfer requirements of the systems in which the fans are used.

For example, if a certain air flow is necessary for a system, an inefficient fan may have a greater number of blades, a greater diameter, and / or a larger motor than a more efficient fan.

Therefore, inefficient fans can cost more than efficient fans in terms of materials and manufacturing expenses, and can occupy valuable system space.

The marketplace, however, often places contradictory constraints upon fan manufacturers.

These constraints are often contradictory because many believe that fans generally need to be larger in order to reduce fan noise and / or airflow.

Increased fan motor and blade speed generally increases the amount of air turbulence moving through the fan—a result that is normally detrimental to fan efficiency.

Turbulence is also a primary factor influencing the noise level of a fan.

For example, larger clearances between fan blade tips and adjacent housing walls can result in lower static pressure capabilities and lower fan efficiencies.

Turbulence within an axial fan can create a phenomenon known as vena contracta, which results in the reduction of the effective cross sectional area of the air inlet.

Such a reduction permits less air to move through the air inlet, thereby reducing the efficiency of the axial fan.

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