# Tag Info

## Hot answers tagged turbomachinery

11

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, due to bleedout as in bodily injury or an aneurysm rupture; incomplete contraction of the heart muscle due to a breakage or damage in the nerves which carry the ...

9

The motor will spin much faster than it does normally when loaded by the pump moving water. This higher speed may wear out something much quicker than during normal operation. The system should be able to handle the higher speed for a few seconds, but most likely it was not designed to operate at that speed long term. The extra robustness probably wasn't ...

4

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 majority of pumps are made of two main components - an electric motor, and the actual pump (impeller and volute) itself. Starting with the pump itself, the ...

3

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 more about this "active area". Can someone maybe expand on that? I've not worked directly with large-scale fuel cell installations (never heard of one, actually) ...

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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 looks organic so solvent seems preferred to mechanical methods like nut shell blast. Corrosion would not be a factor for the metal if solvent is used.

3

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 capacities and heat transfer coefficients tend to be low compared to liquid-liquid. This obviously has advantages for packaging a turbine in a car. Essentially ...

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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.

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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 tunnel, the first naca section was tested in 1935 .... http://www.flyingmag.com/technicalities/technicalities-short-history-airfoils And this link to Sir Frank ...

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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 "rotor" is simply a term the rotating components of the pump. Gear pumps, sliding vane pumps, swash-plate pumps and circumferential piston pumps all have rotors, but none of them ...

3

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 has to get smaller.

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The pump can overheat and the electric motor can burn out.

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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 @Fred said above yes, electric motor will eventually burn out. But as @ Olin Lathrop said yes, it will take lower power while running at high speed (under no load ...

2

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 flowing fluids consist of both pressure energy(a function of fluid pressure) and kinetic energy(a function of flow velocity). The reaction turbines are rotated by ...

2

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 running the compressor stage of the engine and what's left over generates thrust.) In comparison, piston engines cannot support similar fuel burn rates relative to ...

2

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 for no heat exchange. This is important because it makes the equations that we can use much simpler. We want to calculate power, which is work over time. $$P = ... 1 First I would state the question differently. What happens when there is a negative pressure difference across an unpowered hydraulic pump? This is actually a common situation occurring when a pump's electric motor is turned off but pressure still exists downstream because of a compressible accumulator or gravity storage device. There are 3 possibilities in ... 1 I'm not an expert, but that vertical line in the phase is usually when transitioning over a critical rotational velocity of a shaft. This happens when the excitation frequency "transverses" the critical frequency of the shaft. The displacement of the shaft can be derived for an ideal motor (no damping):$$ y = \frac{e\cdot \omega^2}{\omega_n^2 - \...

1

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 proportional to the change in enthalpy of the fluid. Remember the definition of enthalpy is the flow work and the internal energy. Therefore, the enthalpy contains the ...

1

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 participants or carriers." With momentum diffusion, a more concentrated area of fluid momentum is spread out to a larger flow volume and to more fluid ...

1

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 smaller and the density is higher as well as the temperature is increased. This is one reason there are intercoolers as having too high an inlet temperature reduces ...

1

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 fluid being pumped is being strongly sheared whenever the pump is running, and this inevitably produces significant frictional losses. There are many other ...

1

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 work on it.

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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 move up and create lift when wind goes through them. Fans and proppellers go through the air and cause it to move. In a moving car if you hold your hand out ...

1

The real difference is that a wastegate or dump valve is a way of limiting the maximum boost pressure in order to prevent damage to the turbo itself of downstream parts on the other hand variable geometry is intended to improve performance across a range of engine speeds. One disadvantage of simple turbos is that they tend to have a fairly narrow ...

1

When two wheels/pulleys/cogs are connected by a belt, when one of the wheels turns the other one turns in the same direction as the first wheel that turns. When two cogs/gears are positioned so they are touching, when one cog is turned in one direction the other cog turns in the opposite direction. So for your example: The upper left yellow cog turns ...

1

There is a practical limit to the amount of compression that can be achieved in a single stage of an axial compressor. As a general principle, the rotor blades increase the velocity of the gas without much increase in pressure, and the stator blades increase the pressure while reducing the velocity. The changes in the gas velocity are mainly in the ...

1

Determine expected max aircraft speed, and engine thrust at that speed and when stationary. Well, sort of. At the very beginning, you may know the desired thrust at a given condition, but you have to work all the way through the calculations to get the actual thrust at that speed. If the actual thrust and desired thrust don't match, then you would need to ...

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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 E). Point D is located to the left of A because a positive rotation makes A go upwards with $$\omega_{AB} = \frac{v_A}{a}$$ Similarly point E is located to ...

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TL, DR You need a stronger and different fan. Try a vac. What you need to understand about fans Fans are characterised by their power and their flow-pressure curve. Power is pressure times volume flow. Actualy, that's wrong but it's still useful. You fan delivers a certain and has to overcome a pressure difference. Less pressure - more flow and vice versa. ...

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If your cyclone design is correctly separating particles without a major pressure drop; it is working satisfactory and its influence on the flow rate is minimal. If you increase the capacity of your fan and separation starts failing, you may have to modify your design or scale it up. If you do not have a high enough flow rate, you need to get a larger fan. ...

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