Endorfy Fluctus 140 PWM ARGB works, looks come second

… and airflow

The first Fluctus 120 PWM fans marked a great qualitative progress in SilentiumPC production (now Endorfy). Nevertheless, they had their flaws, which the developers are gradually eliminating and, based on the measurement results, the newer 140 mm Fluctus can be said to be a clear improvement. The Fluctus 140 PWM ARGB stands out nicely from other fans in its price category.

… and airflow

With airflow measurements, we can well explain why the test tunnel is shaped the way it is. It doesn’t consist of two parts just so that the “exhaust” can be conveniently clogged for pressure measurements. The anemometer (i.e. the wind speed measuring instrument) is held together by two parts, two formations, through the flanges.

The front part, at the beginning of which the fan is mounted, becomes steadily narrower and from about two thirds of the way through the cross-section is smaller than that of a 120 mm fan. The reason for this is that the cross-section of the anemometer is always smaller than that of the fans tested. The taper towards the anemometer fan is as smooth as could be chosen and the tunnel walls are smooth. This has minimized the occurrence of unnatural turbulence.

The difference between the cross section at the intake (fan under test) and at the constriction point (anemometer) also means a difference in dynamic pressure, the principles of the Venturi effect apply here. In order to avoid distortion at this level and to ensure that the fan airflow is not different from what it actually is, the Bernoulli equation must be applied to the measured values (for maximum accuracy, the calculation also takes into account the internal cross-sectional area of the anemometer, i.e. its inactive part ). After all this, it is again possible to confront our results with the paper parameters.

We use an Extech AN300 anemometer with a large 100 mm fan for the measurements. Its big advantage over other anemometers is that it is made for bidirectional sensing. This allows tests at different fan orientations. However, the “pull” position is more suitable or accurate for measurements, even though it may not seem so at first glance, but we’ll explain.

Here, we get to the second part of the tunnel, the part behind the anemometer. It is part of the whole device, mainly to allow a laminar flow of air to arrive at the rotor of the anemometer. Otherwise, uncontrolled side whirls would be reflected in the results, which are inconsistent with accurate measurements. Therefore, we will test the flow in the pull position. If anyone would like us to elaborate more on this topic, we can elaborate further at any time in the discussion below the article. Ask away. 🙂

The rear of the tunnel ensures, among other things, that the air supply to the anemometer fan is laminar

In regard to the anemometer, we shall return for a bit to noise measurements and to setting modes according to fixed noise levels. It may have occurred to you as you were reading that the anemometer fan is also a source of sound that needs to be filtered out when measuring fans. For this reason, we insert a securing pad between the frame and the anemometer fan before each measurement and mode setting according to the fixed noise level. This, by the way, also holds the anemometer fan during static pressure measurements.


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Comments (3) Add comment

  1. I have several general questions.

    I see how the exhaust airflow pattern is often commended on. By how much does airflow pattern affect cooling performance? For example, assuming two fans have identical airflow rate on a thin radiator. One fan has cylindrical exhaust while the other has conical exhaust. Alternatively, one has a larger fan hub and the other has a smaller one. Or just different blade design in general. Does cooling performance differ, and if so, by how much? How about for case fans? How about on the intake side, does airflow pattern differ there?

    The wind tunnel is made free of dust before testing. By how much does dust settled on the wind tunnel/fan blades etc affect airflow and noise? Would a thin layer significantly affect the results?

    1. Great questions. We have had the ones from the first paragraph jotted down for a while and we will deal with them later in specialized tests. We just have to work our way through the other topics. 🙂

      As for the effect of fan “dirtiness” on air flow, I wonder how this could be tested. Of course, we keep the wind tunnel as clean as possible (it is even stored in a vacuum chamber) and I don’t think it is a good idea to risk changing the friction or reducing the anemometer speed by some sediments from the tested fan. But we’ll figure something out. For this purpose we could use some of the prototype tunnels that preceded the final one we are using. They have some imperfections, but they should be suitable for this purpose.

  2. I’m in love with these deeply scientific reviews. No other reviewer, ever, anywhere, went to such lengths and details in their reviews, especially about pc fans. Because of them I’m getting now 2x Endrofy Fluctus 140 argb for a top exhaust on case with grill+ dust filter. Having read all other reviews, I do prefer them over Pure Wings 3, they seem to be more efficient and more quiet at similar settings.
    Thank you!

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