Fan blade physics... need info...
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From: Castro Valley, CA
Fan blade physics... need info... Does anyone know whether a swept fan blade (the "swirl design") run in its opposite direction (by switching the electrical leads) will generate the same flow as when run in the appropriate rotation?
It makes sense to me that a simple straight rectangular bladed fan would be reversible by simply changing its direction of rotation, without losing any airflow. But I get the feeling that a swept fan blade design would not be as efficient when run "backwards"...
Hence, is it always necessary on a swept blade fan to take off the blade and turn it around for optimal airflow? Or do you still generate most of the airflow anyway?
Thanks in advance for any info,
Rich
It makes sense to me that a simple straight rectangular bladed fan would be reversible by simply changing its direction of rotation, without losing any airflow. But I get the feeling that a swept fan blade design would not be as efficient when run "backwards"...
Hence, is it always necessary on a swept blade fan to take off the blade and turn it around for optimal airflow? Or do you still generate most of the airflow anyway?
Thanks in advance for any info,
Rich
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TECH Resident
Joined: Jan 2004
Posts: 832
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From: Castro Valley, CA
There are quite a few reversible fans out there, but I was just wondering if most achieved this by flipping the blade around.
You'll see, many times, threads on this forum that discuss overheating... and we're always talking about making sure the fans are wired correctly so that they're either pushing or pulling like you think they are.
But maybe it's a whole new ballgame with a swept-blade fan. Simply swapping the leads will get the blade going in the right direction, but airflow is (much?) less than that generated by orienting the leading edge of the fan correctly.
You'll see, many times, threads on this forum that discuss overheating... and we're always talking about making sure the fans are wired correctly so that they're either pushing or pulling like you think they are.
But maybe it's a whole new ballgame with a swept-blade fan. Simply swapping the leads will get the blade going in the right direction, but airflow is (much?) less than that generated by orienting the leading edge of the fan correctly.
