5

The work is surely path dependent; you can estimate a fast passable value in two way. Isothermal, as in the case when several stages with intercoolers are used (SI Units) KWiso = 2.78*10^-4 * (VolFlowRate) * P1 * LN( P2/P1 ) And Adiabatic with costant ratio of specific heats (k) (SI Units) KWad = 2.78*10^-4 * k /( k-1 ) * (VolFlowRate) * P1 * [(P2 / P1)^(...


5

There are two aspects to this. First is that the main advantage of hydraulics is that is provides a compact means of greatly multiplying force but in compressing gasses you have to a huge amount of work on the gas itself so the constraint is the power input so you are always limited by the capacity of the motor driving the compressor. Consider that the ...


5

Don't do it!! Just buy a pressure regulator to put between the two tanks that will decrease the pressure to below 125. You can get these for \$17 at home depot (https://www.homedepot.com/p/Husky-1-4-in-NPT-Regulator-with-Gauge-41155HOM/205331831) and maybe even cheaper elsewhere. I'm terrified of the tank exploding and covering me with shrapnel. This is a ...


4

An axial compressor accelerates a flow of air to high speed. All the molecules in that parcel of air have that speed superimposed on their random vibrational motion. The idea of a diffuser is to get the fast-moving air to pile up against itself, slowing it down (i.e., decreasing its kinetic energy) and causing its pressure to increase (by increasing the ...


4

As the air moves from the center out it accelerates in a pattern similar to a hurricane. the velocity vector angle changes to reduce the rotational whirlpool and angular momentum component of the airflow but add to its pressure and centripetal momentum. The blade angle of attack to airstream follows air velocity vector more or less under 14 degrees to give ...


3

That's a pretty qualitative question, but by and large, air conditioner compressors are not really inherently dangerous to be around. Danger comes in the form of unqualified people working on or installing systems. In a direct comparison, split systems are going to be larger than window units and will, therefore, have potential for more spectacular ...


3

Per the Plunger Pump Wiki: A plunger pump is a type of positive displacement pump where the high-pressure seal is stationary and a smooth cylindrical plunger slides through the seal. This makes them different from piston pumps and allows them to be used at higher pressures.


3

Notice that the "shapes" are in a right angled bend where the flow changes directions. Sometimes vanes are placed in right angled bends to reduce shock losses by reducing the turbulence of the flow as it goes through the bend. The "shapes" the picture appear to be on the outside of the bend, in which case they have been placed there to reinforce the bend ...


3

Yes indeed, air can be compressed by pressurized liquids directly as you suggest. However, there are problems that accompany this sort of scheme. First, if the gas is significantly soluble in the liquid, then the liquid will pick up gas while being pressurized which will then come forcibly foaming out of solution when the pressure is released. Second, you ...


3

The evaporator is usually in the area to be cooled ie where the people work, read etc As the compressor takes space and tends to be noisy it is located away from that area. That makes the system in the « active » area smaller and quieter.


3

That is on the high pressure end of normal pneumatic conveying blowers, but they are out there. See the notice at the bottom of the attached chart. http://www.hsiblowers.com/products/high-speed-turbo-blowers.html You don't want a high pressure compressor, you just need to find the right compressor that will deliver at 18 psi. You need to specify if the ...


3

There is a simple reason and a useful added benefit. As you compress air of a fixed mass it occupies less volume. If you give it more space again, it will immediatly decompress and the multiple stages become useless. If you give it just enough space to occupy at its current pressure, the air will compress further. You could reduce space by reducing the ...


3

Google dugout aeration windmill system. There are various makers. Here's one: https://koenderswatersolutions.ca/ The compressor on them does one cycle per revolution of the windmill. While not as slow as 1 rpm the one I have is only rarely over 50 rpm. Internally they are a diaphragm pump. This means you only have the leaking of the valves to contend with....


3

They aren't universally. Centrifugal fans use all sorts of blade configurations - forward, backward, radial, curved (either forward of backward) and straight (also prismatic or aerofoil). Different blade configurations give different fan characteristics, some relating to how effective it is as a fan (pressure, flow rate) and some relating to things like how ...


2

In general every compressor (axial and radial) will deliver a certain flow rate depending on the back-pressure down stream of the compressor. So by changing the pressure difference over the compressor: for example closing a throttle upstream or downstream of the compressor the flow rate will change accordingly. This can also be achieved by changing the ...


2

The generic equation for mass flow through a cross-section of area $A$, traveling at velocity $V$ is $$ \dot m = \rho \, V \, A $$ where $\rho$ is the density of the fluid and $\dot m$ is the mass flow rate. If the molecular weight, temperature, and pressure of the fluid are fixed, then density is fixed too. That leaves $V$ and $A$ to play with. Since $...


2

Such high pressures can be achieved via diamond anvil cells (DAC). The heart of these cells are two diamonds mounted on tungsten seats symmetrically in front of each other which are separated by metallic plate. Metallic plate has an aperture with loaded sample (gas, crystal, powder, etc.). These diamonds are then brought closer to each other by tightening ...


2

One practical problem, if it's saturated steam, is that by increasing pressure, you're increasing the condensation point, so a lot of the steam will keep turning to liquid water without any considerable pressure growth. If you take 10l of dry air at 1 bar and compress it to 2 bar, you get about 5l of the compressed air. But if you take saturated steam - you'...


2

The elephant in the room is that while gasses are compressible, hydraulic oil is only negligibly so. This difference has two major effects: Firstly, the output volume flow is limited by the intake volumetric flow divided by the compression ratio. Let's say we have a hypothetical compressor that pulls in 10 L of air per second at STP, and raises the ...


2

You are describing Vapor-compression Evaporation. According to wikipedia, since any real compression will also heat the gas "The compression work will deliver the steam superheated if compared to the theoretical pressure/temperature equilibrium." IMO this should be verified with the actual figures from your process design etc., you don't want liquid water in ...


2

A 3Hz pulsating hum-- noise that is getting louder and softer at 3Hz. Yes, I agree that would be quite annoying. Since this is a residential unit in the US, both the compressor and the fan are run with single phase asynchronous motors. Almost certainly, they are four pole with an 1800 RPM synchronous speed, running about 1750 RPM or so, depending upon ...


2

No, because the pump is designed to limits and if you exceed its working or maximum pressure then, for example, its seals fail and it just does not pump any more.


2

\begin{equation} {\displaystyle \Delta S=nC_{v}\ln {\frac {T}{T_{0}}}+nR\ln {\frac {V}{V_{0}}}.} \end{equation} Snipped from Entropy: wikipedia. See also 5.4 Entropy Changes in an Ideal Gas, which I recommend you read starting at Section 5. It's taken from some of MIT's online resources. As Chemomechanics says in his coments, the necessary condition is ...


2

What you describe is quite common where there isn't any problem with power and noise. It requires a bit more sophistication to manage the superheat. And yes, you need to quiet the thing some. I replaced a '60s era 20 ton compressor in a restaurant's dining room AC closet while they were serving dinner. This is also a good idea near the coast to keep the salt ...


2

Compressors are a combination of rotors and stators along a structure with reducing cross-section area. The rotors spin and push air down the compressor, but due to their spin there arises a circumferential velocity component to the air flow. The stators don't revolve (hence the name) and they "straighten out" the flow, so as to direct the airflow ...


2

I have been in 100 steel mills and never noticed a nitrogen system. However it seems they could use inert gas blasting somewhere. And nitrogen would be so cheap and convenient because steel mills will generally have a cryogenic oxygen plant. Generally they are off site and may be owned by someone like Linde. Very simple to lay a nitrogen pipe next to the ...


2

A 10 or 25 psig overpressure of a tank is well into a potential failure for the tank. The 140 psig safety valve is used because that accounts for the true pressure capability of the tank plus the tolerance in lift pressure for the safety valve. If you replace it with a 150 psig valve, you are risking the tank building up pressure past it's breaking point to ...


2

Start with the first law. $$dU = \delta q + \delta w$$ Isentropic sets $dS = \delta q /T = 0$, giving $dU = \delta w$. For an ideal gas with a constant specific heat, $dU = C_v dT$. This gives the equation being used. $$\Delta U = C_v \Delta T = w $$ If temperature decreases, work is negative, meaning it is done by the gas. Alternatively, if temperature ...


1

It is usually a completely different group of people doing compressor aerodynamic design versus overall thermodynamic cycle design. The compressor aero group, using a variety of computer simulation codes (ranging from simple spreadsheets all the way up to 3 dimensional unsteady CFD) are going to generate a "compressor map". The compressor map gives the ...


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