hias9 said:
Of course it has a temperature sensor and temperatures are monitored. Just measuring motor temperature would not be precise enough to make conclusions if airflow improved or not I think.
Even with just one built in temperature sensor, you can determine if the airflow changes also change the motor temperature in the direction you want, as long as you perform several test runs of each airflow redirection version to average the readings you get.
Now, if you want to determine what specific areas of the motor are changing temperature and to what degree; you would need to instrument the entire motor as thoroughly as possible with many sensors, and record that data with whatever system you would have used for the airflow recording (which would also require instrumenting the motor with many sensors to actually track the airflow).
Or you can use an FLIR camera mounted where it can "see" the motor, you can record this data (or observe it directly on-screen), and not have to instrument the motor *at all*, yet still see the entire motor. If each side is expected to be different results, then you would need two FLIRs to simultaneously meausure both.
So, what data collection system were you going to use to log the airflow measurements?
Almost certainly you can use the same (or equivalent) system to log the temperature measurements.
Measuring the temperature is a MUCH more direct way to get the results you are after, because you don't actually care what the specific airflow is. You only care what the *temperature* is--if the temperature stays low, then the airflow is doing whatever you wanted it to do.
If you insist on measure the airflow, you are probably going to have to invent something to do it that can mount to the spinning motor casing (assuming an outrunner or hubmotor), and then wirelessly transmit the data to a collection system, to log it for your test runs.
But I really think this is overthinking the problem, and you'd get perfectly usable results by simply measuring the motor temperature in one or a few places, then performing several test runs for each version of airflow redirection, collecitng the temperature data for each, averaging the several runs within a version, and then comparing each of these averages for the different versions, to tell you which version worked better.
It might require an iterative approach to designing the airflow redirections, retesting, redesigning, retesting, but it'll get you where you want to be with technology you already have built in, and/or existing cheap technology (wireless temperature sensors and a receiver that can log all of their data together for each test run).
FWIW, anything you use to directly measure airflow is going to change the airflow, becuase it has to be *in* the airflow.
Just like anything you use to directly measure temperature is going to change the temperature, because it is in contact with the thing being measured.
How much each of those thigns changes the measurement depends on the scale of the property being measured, vs the size/shape of the airflow measurement devices, or the mass of the temperature measuring devices, and how many of each there are, and where they are.