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An axial fan is a type of fan that causes gas to flow through it in an axial direction, parallel to the shaft about which the blades rotate. The flow is axial at entry and exit. The fan is designed to produce a pressure difference, and hence force, to cause a flow through the fan. Factors which determine the performance of the fan include the ...
In reality the fan system efficiency is often in the range 0 to 60% (i.e. <); it is lowest for small fans or inefficient operating points (e.g. throttled flow or free-flow). The efficiency is a function of the total losses in the fan system, including aerodynamic losses in the fan, friction losses in the drive (e.g. belt), losses in the ...
Centrifugal fans are, like axial fans, constant-volume devices, meaning that, at a constant fan speed, a centrifugal fan moves a relatively constant volume of air rather than a constant mass. This means that the air velocity in a system is fixed, but the actual mass of air flowing will vary based on the density of the air.
The affinity laws (also known as the "Fan Laws" or "Pump Laws") for pumps/fans are used in hydraulics, hydronics and/or HVAC to express the relationship between variables involved in pump or fan performance (such as head, volumetric flow rate, shaft speed) and power. They apply to pumps, fans, and hydraulic turbines. In these rotary implements ...
A High-volume low-speed fan. A high-volume low-speed (HVLS) fan is a type of mechanical fan greater than 7 feet (2.1 m) in diameter. [1] HVLS fans are generally ceiling fans although some are pole mounted. HVLS fans move slowly and distribute large amounts of air at low rotational speed– hence the name "high volume, low speed."
The bypass ratio (BPR) of a turbofan engine is the ratio between the mass flow rate of the bypass stream to the mass flow rate entering the core. [1] A 10:1 bypass ratio, for example, means that 10 kg of air passes through the bypass duct for every 1 kg of air passing through the core.
The axial fan is often contained within a short section of cylindrical ductwork, to which inlet and outlet ducting can be connected. Axial fan types have fan wheels with diameters that usually range from less than a foot (0.3 meters) to over 30 feet (9.1 m), although axial cooling tower fan wheels may exceed 82 feet (25 m) in diameter.
The tip-speed ratio, λ, or TSR for wind turbines is the ratio between the tangential speed of the tip of a blade and the actual speed of the wind, v.The tip-speed ratio is related to efficiency, with the optimum varying with blade design. [1]