12
votes
What is the physical meaning of pulse rate and blood pressure, from a turbo machinery point of view?
high pulse rate + low pressure means low pumping efficiency of the heart. this can be caused by:
leaking valves, especially the main aortic valve, due to disease or calcification;
low blood volume, ...
- 14.3k
4
votes
Accepted
What's the difference between impeller and rotor in centrifugal pump?
An impeller is the type of rotor found in a centrifugal pump, in fact another name for "centrifugal pumps" is "impeller pumps". Many different types of pump have rotors.
The pump &...
- 2,145
4
votes
What will happen if I run a submersible pump without water?
There are good answers here, but just wanted to clarify some points. It's important to consider what the liquid (in this case water) is used for in the pump.
To begin with, it helps to see that the ...
- 41
4
votes
Advantages of hydrogen gas turbine over fuel cell
I've read in one of Smil's books that fuel cells are somehow limited (in what sense I'm not sure anymore but I believe it was power output) by their "active area". I'm having difficulties learning ...
- 532
3
votes
Accepted
How should one clean the blades of a turbomolecular pump
Acetone or other ketones are used to clean auto engine internals of "varnish"( which looks similar to your deposits). This is for research purposes ,not general engine cleaning. The material ...
- 6,112
3
votes
Accepted
What gives gas turbine/turbojet engines such high energy density?
Turbojets and turbofans support extremely large mass flow rates of air & fuel through them, relative to their weight. (The majority of the work performed by burning that fuel is taken up by ...
- 14.3k
3
votes
Turbocompressor spool geometry
The compressor is compressing the gas, so the same amount of air (on a mass or molar basis) occupies less volume. If the goal is to keep the velocity approximately constant, the cross sectional area ...
- 1,022
3
votes
Accepted
Why regenerator "wheels" in a turbine engine?
The main advantage of a rotary regenerator is that you can pack a lot more surface area into a given volume than with a shell and tube type device important for gas-gas heat exchange where heat ...
- 15.2k
3
votes
What is the purpose of a vacuum cleaner's bypass valve?
It’s purpose is to allow sufficient air to cool the motor when the filter / dirt bag is blocked - otherwise it will overheat and could catch fire.
- 15.5k
3
votes
When were airfoil cross-sections first used in turbine blades?
Good description in the link, but curved surfaces were in use as sails around 800 years ago and Bernoulli came up with his formula , Ludwig Prandtl was testing sections in 1017 in his large wind ...
- 15.5k
3
votes
Accepted
Why do EMD turbochargers have so many blades?
Think of blades as something pushing on the fluid. There is a pressure side and a suction side to each blade. Pressure varies from the low on suction side to the high on the pressure side.
Any work ...
- 1,304
3
votes
Doubt on a shaft-turbine-generator system
I am not entirely certain about your question but I think, it basically boils down to this equation
$$M = I \alpha $$
where:
M is the torque applied
I is the mass moment inertia of all rotating ...
- 24.3k
2
votes
Accepted
Does the turbine outlet affect the power generated by the turbine ?
The turbine referred to, in your text book must be a specific type of turbine, namely reaction turbine. Reaction turbines utilise mainly the pressure energy of flowing water to produce Power. The ...
- 349
2
votes
What will happen if I run a submersible pump without water?
There are pretty good answers but I feel like non of them are complete answers.
99% of electric pumps are Induction motor. So for rest of the discussion I will be referring to induction motor.
As @...
- 197
2
votes
Why doesn't axial turbomachinery blades block fluid from flowing?
The blades are set at an angle which causes them to "dig in" to the air and propel it through the fan disc as the disc rotates. In this manner, the blades add kinetic energy to the air by performing ...
- 14.3k
2
votes
Power/Efficiency of expanding air-flow
Well here goes.
Given that there is no heat transfer to the surroundings, indicated by the neglection of heat to the machine, this means that we can assume the system to be adiabatic - a fancy term ...
- 21
2
votes
Tesla's Turbine in Real Life
An inspection of his patent reveals that his pump relies on the viscosity of the fluid to perform work- that is, the fluid is coupled to the impelling cylinder by shear forces alone. This means the ...
- 14.3k
2
votes
Why do EMD turbochargers have so many blades?
EMD 710's use hybrid turbochargers.
These are spun by a gear driven clutch at low load and by exhaust gas at high load. What this means is that they can optimize the blades without worrying about low ...
- 6,544
2
votes
Axial compressor: How does it work that the stator vanes diffuse the flow to build up pressure, but also the flow area reduces?
The device has to be designed so that each stage does its job.
The stator reduces the high velocity out put of a stage to a lower velocity, increasing the pressure. But the subsequent rotary section ...
- 6,544
2
votes
Accepted
What is the meaning of different temperature limits printed on turbo charger's boiler plate?
From ABB Operation Manual TPS57-F32
Operation above the indicated values $n_{B_{max}}$, $t_{B_{max}}$ can considerably shorten the recommended replacement intervals. In such cases, we recommend that ...
- 2,467
1
vote
Effect of flow through a static hydraulic pump on its RPM
First I would state the question differently. What happens when there is a negative pressure difference across an unpowered hydraulic pump? This is actually a common situation occurring when a pump's ...
- 366
1
vote
How is the ideal Euler line on a pump curve derived?
You'll notice that at one point on the web page you linked, it says 'we assume that the flow enters exactly normal to the impeller, so tangential component of [lab frame] velocity [at the inlet] is ...
- 851
1
vote
How to interpret the phase plot from an accelerometer on vibrating machinery
I'm not an expert, but that vertical line in the phase is usually when transitioning over a critical rotational velocity of a shaft.
This happens when the excitation frequency "transverses" ...
- 24.3k
1
vote
Accepted
Accounting for pressure energy in Euler turbine/pump equation
If you examine a derivation of the Euler work equation (http://web.mit.edu/16.unified/www/SPRING/propulsion/notes/node91.html), you will see that the change in angular momentum of the fluid is ...
- 523
1
vote
Advantages of hydrogen gas turbine over fuel cell
Hydrogen combustion has some advantages over fuel cells, namely rate of consumption allows significant power output.
Uses existing technology, gas turbines can be easily modded to burn any gaseous ...
- 544
1
vote
What is the diffusion process that takes place in a diffuser/stator?
The word "diffuse" is used in different contexts in both engineering and in the vernacular. A general definition would be similar to, as a verb, "spread out over a larger area, space, or number of ...
- 417
1
vote
Relation between Inlet and Outlet mass flow rate for a turbocharger?
The mass flow across a turbocharger is constant:
If X kilogrammes of air go in then X kilogrammes of air come out.
However if the pressure is twice the inlet pressure then the output volume is ...
- 15.5k
1
vote
Why doesn't axial turbomachinery blades block fluid from flowing?
The blades are basically small helicopter wings. They are set to a small angle to the shaft so they create "lift", but because they can't move up with the lift they move the air.
However they can ...
- 22.1k
1
vote
Accepted
Working of a fan or propeller
A table fan or a plane propeller have blades, pitched into an angle, which cuts into stationary air and acelerates it forward.
They are basically rotating wings, but working in reverse sense. Wings ...
- 22.1k
1
vote
Mechanical Linkage Question - Velocity Diagram
This is how to approach this problem:
The rule is that the relative rotation center between two bodies (point B) lies on the line connecting the instant centers of rotation of each body (points D and ...
- 723
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