Conversion of high velocity airflow into a pressure

[T C]

TL;DR Summary

A blower creates a flow at 337 m/s. What's the pressure level that can be achieved with such velocity.

We know blower compressors i.e. compressors that use a blower to create high velocity for injecting air/fluid to higher pressure and that's available in market. Now, suppose we have such a blower type compressor that can create a flow of air/gaseous fluid of 337 m/s. Question is, what maximum pressure level, at which the flow can be injected?

 

[Lnewqban]

That maximum pressure is not a function of the velocity of the flow.
Your centrifugal compressor only increases the pressure of certain mass of air or gas by transferring mechanical energy to it via centrifugal effect.
The velocity at which that mass flows out of the machine is not very important regarding the pressure differential.

Copied from
https://en.m.wikipedia.org/wiki/Centrifugal_fan

"The property that distinguishes a centrifugal fan from a blower is the pressure ratio it can achieve. In general, a blower can produce a higher pressure ratio. Per the American Society of Mechanical Engineers (ASME), the specific ratio - the ratio of the discharge pressure over the suction pressure – is used for defining fans, blowers and compressors. Fans have a specific ratio of up to 1.11, blowers from 1.11 to 1.20 and compressors have more than 1.20."

 

[T C]

Ok. Let's consider it in another way. If that velocity will be used to inject that flow to higher pressure, what can be the maximum pressure level?

 

[Lnewqban]

Sorry, perhaps I am not understanding your explanation.
Trying to put your question in perspective:

Imagine that you have to increase the pressure of an inflated pneumatic tire that now holds 20 psi up to a new pressure of 30 psi.
Would you be concerned about the velocity of the injected air or about the pressure that your compressor is able to develop?

A small compressor would take longer to do the job because it compresses less mass of air per unit of time.
By reducing the diameter of the hose or the valve, you could achieve a greater velocity at the point of injection, but that would not make any difference.

Note that you need a hose or duct in order to keep certain pressure within the flow.
Inflating a balloon directly with your mouth is not the same as blowing into the balloon from a distance.

Please, see:
https://www.nrel.gov/docs/fy03osti/29166.pdf

For most types of centrifugal fans and blowers, their performance curve indicates that they can develop more static pressure when the volumetric flow is minimum and vice-verse.

 

[T C]

I want to mean that if the dynamic pressure at that velocity is converted to static pressure, then at what level the pressure will rise?

For most types of centrifugal fans and blowers, their performance curve indicates that they can develop more static pressure when the volumetric flow is minimum and vice-verse.

It simply means that the higher the velocity, the greater will be the rise in pressure. Because less volume means less mass and higher velocity.

 

[Lnewqban]

I want to mean that if the dynamic pressure at that velocity is converted to static pressure, then at what level the pressure will rise?

You may be talking about stagnation pressure, which happens when a fluid in movement comes to a full stop and its dynamic energy rises the static pressure inside a vessel?
If so, this may help:
https://en.m.wikipedia.org/wiki/Stagnation_pressure

It simply means that the higher the velocity, the greater will be the rise in pressure. Because less volume means less mass and higher velocity.

That statement is not accurate, sorry.
There is no higher velocity of the supplied flow when a blower is increasing discharge pressure the most.
Just like the rpm's of an engine facing a step hill would naturally decrease, when the duct system imposes a greater resistance to the flow (increased inlet-outlet pressure differential), the rate of flow is sacrificed.

Discharge velocity [m/s] = Volumetric flow [m^3/s] / Cross area of discharge duct [m^2]

 

[russ_watters]

We know blower compressors i.e. compressors that use a blower to create high velocity for injecting air/fluid to higher pressure and that's available in market.

Can you provide a link to the product you are looking at and a sketch of the system it will be connected to? Then we can help you interpret its/the system's performance.

 

[T C]

Just search google with "blower compressor" and you can see many examples.

 

[russ_watters]

Just search google with "blower compressor" and you can see many examples.

So in other words, "we know" means you don't actually know if there is a product that meets your needs? It really means "I think"?

Either way, that doesn't tell us what you are trying to do. If I tell you 30psi, does that help? How about 300psi? The answer here is that as long as what you want to do is physically possible (doesn't break the laws of themodynamics), you can find a product to do it. But first you need to decide what you want to do.

As usual, your description is vague and implies some things that aren't true, but it is hard to pin down because it is vague. So we're forced to guess. My guess is this:

337m/s is just under the speed of sound. So if we go with choked flow, then any compressor worthy of the name will do what you want, with pressures up to hundreds of psi for basic/normal compressors. Is that what you want?

 

[T C]

I just want to know one thing, if that 337 m/s velocity is converted to pressure, then what would be the pressure rise of the input flow considering the fluid to be gaseous i.e. compressible.

 

[russ_watters]

I just want to know one thing, if that 337 m/s velocity is converted to pressure, then what would be the pressure rise of the input flow considering the fluid to be gaseous i.e. compressible.

Then it looks like you want to find stagnation pressure. @Lnewqban gave you the equation for it in post #6. What did you get for an answer when you calculated it?

 

[Tom.G]

If you are looking for the wind force on a surface, try this site:
https://www.engineeringtoolbox.com/wind-load-d_1775.html

The answer I got with your wind speed (337m/s) was: 68141 N/m²

Cheers,
Tom

 

[T C]

It that's converted to barA pressure, then how much that will be?

 

[Tom.G]

Ask Google to do the conversion and tell us. That's what I would do.

 

[russ_watters]

Ugh. I was hoping to force more effort than that, Tom, but this is truly ridiculous. Thread locked.

[Edit] BTW, I don't think that calculator is taking into account compressibility, which makes the answer lower than what I got. But @T_C can plug and chug the provided equation - and feel free to PM me with your answer for a check.