PC Fans

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==Parameters==

Static pressure is the pressure created in front of the fan within an enclosure. Airflow is the volume of air moved per unit time. A fan's output is characterized in terms of maximum static pressure and maximum airflow, but '''it does not hit both maxima at once'''. Maximum airflow is achieved when completely unobstructed. As the amount of obstruction increases, airflow is reduced, and static pressure increases. At a given level of output, airflow is roughly inversely proportional to the square root of static pressure. Each fan has a performance curve relating airflow to static pressure (technically, a curve per PWM level). The environment defines the impedance curve, and the real pressure and airflow are specified where these two intersect.

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! variable !! when speed changes !! when density changes

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Static pressure is the pressure created in front of the fan within an enclosure. Airflow is the volume of air moved per unit time. A fan's output is characterized in terms of maximum static pressure and maximum airflow, but '''it does not hit both maxima at once'''. Maximum airflow is achieved when completely unobstructed. As the amount of obstruction increases, airflow is reduced, and static pressure increases. At a given level of output, airflow is roughly inversely proportional to the square root of static pressure. Each fan has a performance curve relating airflow to static pressure (technically, a curve per PWM level). The environment defines the impedance curve, and the real pressure and airflow are specified where these two intersect.

This is of great relevance when putting fans on radiators, and to a lesser extent behind screens/filters. A fan optimized for static pressure might be able to push more flow through such obstacles than one designed purely to maximize unimpeded airflow.

==Accessories==

PC Fans: Difference between revisions

Dank (talk | contribs)

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 ==Parameters==
-Static pressure is the pressure created in front of the fan within an enclosure. Airflow is the volume of air moved per unit time.  A fan's output is characterized in terms of maximum static pressure and maximum airflow, but '''it does not hit both maxima at once'''. Maximum airflow is achieved when completely unobstructed. As the amount of obstruction increases, airflow is reduced, and static pressure increases. At a given level of output, airflow is roughly inversely proportional to the square root of static pressure. Each fan has a performance curve relating airflow to static pressure (technically, a curve per PWM level). The environment defines the impedance curve, and the real pressure and airflow are specified where these two intersect.
+{| class="wikitable floatright"
-{| class="wikitable"
 ! variable !! when speed changes !! when density changes
 |-
@@ Line 190: / Line 188: @@
 |-
 |}
+Static pressure is the pressure created in front of the fan within an enclosure. Airflow is the volume of air moved per unit time.  A fan's output is characterized in terms of maximum static pressure and maximum airflow, but '''it does not hit both maxima at once'''. Maximum airflow is achieved when completely unobstructed. As the amount of obstruction increases, airflow is reduced, and static pressure increases. At a given level of output, airflow is roughly inversely proportional to the square root of static pressure. Each fan has a performance curve relating airflow to static pressure (technically, a curve per PWM level). The environment defines the impedance curve, and the real pressure and airflow are specified where these two intersect.
+This is of great relevance when putting fans on radiators, and to a lesser extent behind screens/filters. A fan optimized for static pressure might be able to push more flow through such obstacles than one designed purely to maximize unimpeded airflow.
 ==Accessories==