Search results
Results from the WOW.Com Content Network
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 ...
Actual cubic feet per minute (ACFM) is a unit of volumetric flow. It is commonly used by manufacturers of blowers and compressors. [1] This is the actual gas delivery with reference to inlet conditions, whereas cubic foot per minute (CFM) is an unqualified term and should only be used in general and never accepted as a specific definition without explanation.
To further confuse the issue, a centrifugal fan is a constant CFM device or a constant volume device. This means that, provided the fan speed remains constant, a centrifugal fan will pump a constant volume of air. This is not the same as pumping a constant mass of air. Again, the fan will pump the same volume, though not mass, at any other air ...
A fan may have two maps, one for the bypass (i.e. outer) section and one for the inner section which typically has longer, flatter, speed lines. Military turbofans tend to have a much higher design fan pressure ratio than civil engines. Consequently, the final (mixed) nozzle is choked at all flight speeds, over most of the throttle range.
A commercial fan delivering air at 20 miles per hour (mph) requires about 64 times as much power as a similar sized fan delivering air at five mph. [8] Airspeed, combined with fan "effectiveness," means that when the objective is to cool people or animals, very large, low-speed commercial fans are more efficient and effective than small high ...
A graphing calculator is a class of hand-held calculator that is capable of plotting graphs and solving complex functions. While there are several companies that manufacture models of graphing calculators, Hewlett-Packard is a major manufacturer. The following table compares general and technical information for Hewlett-Packard graphing ...
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Q = Volumetric flow rate of air in cubic feet per minute (cfm) Vol = Space volume L × W × H, in cubic feet; In metric units = where: ACPH = number of air changes per hour; higher values correspond to more ventilation; Q = Volumetric flow rate of air in liters per second (L/s)