Questions tagged [turbine]

A set of rotating blades that extracts power from a flow. In aviation this primarily refers to the section of a gas turbine that extracts power from the combusted gases, as part of a turboshaft, turboprop, or jet engine.

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Could high density abrasion-resistant ceramic turbine blades allow for the use of borane fuels?

In the late 1950s the U.S Air Force searched for a fuel with similar characteristics to jet fuel but with higher energy density allowing longer flight range for bombers. In 1947 the British had ...
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Has anyone burned hydrogen in a turbine?

I am just wondering if supplying compressed hydrogen to a turbine would be a better fuel as it has three times the octane rating of kerosene. It just seems better all around.
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What turbine blade alloy did the Jendrassik Cs-1 use?

Wikipedia says that the first turboprop aircraft engine was the Jendrassik Cs-1 invented in Hungary by György Jendrassik. It says it was supposed to run at 1000 hp but "combustion problems" limited ...
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What is the definition of “blade scatter” in gas turbine compressor dynamic balancing?

Can someone help me define “blade scatter” gas turbine compressor dynamic balancing?
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Is it possible to drive a prop directly from a jet engine without a gearbox?

I'm studying turbojets, turbofans, and turboprops. I can see that, for the latter engine configuration, a gearbox is necessary so that the propeller rotates at a lower velocity than the main ...
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Which are typical rpm values for aeronautical turbines?

I wonder which of these has higher or lower rotational speed: turboshaft turbofan turbojet turboprop Does anybody know the typical speeds for these kind of engines?
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How do the contrarotating turbines work in the F-119-PW-100?

I was reading about the F22 Raptor and found out that its powerplants use contrarotating turbines. How does this work Also, if the spools and their connected compressors are rotating in opposite ...
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Turbines in jet engines

I was reading this thread and in the answer, the person wrote "For example, the turbine blades are replaced after a set number of turbine cycles and/or after a set number of hours, which are lesser ...
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How can I calculate turbofan efficiency as a function of turbine inlet temperature?

I know that increasing the turbine inlet temperature (TIT) increases the overall efficiency of the jet engine. So I wanted to find the overall efficiency as a function of TIT. I used the equations ...
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Turbine blade manufacturing/assembly process

I want to know the process for manufacturing turbine blades and the companies that are involved. Who makes the turbine blades? Who applies the thermal barrier coating? Who repairs the blades? Let's ...
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Can you identify this jet turbine stage?

I was just wondering if anyone could give me any info about this turbine rotating stage I picked up at a yard sale today. The stage measures 8-1/2" to the outside of the blades. The only markings I ...
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Do the compressors and turbine rotate at the same speed?

Since the turbine and the compressors are connected to each other via a common shaft, do they both rotate at the same speed. Because I've read that in some jet engines (single spool engines) they don'...
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How often are turbine blades in jet engines replaced?

How often are the turbines in the hot section of the jet engines replaced due to deteriorated TBC? or just how often are they replaced? lets say for CFM56-7
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At what point is a turbine powered ducted propeller considered a turbofan?

Turboprop Propellers can be ducted for extra thrust. What are the criteria for determining that the engine is no longer a ducted propeller design, but a turbofan? Does there have to be a type of ...
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What's that rattling noise from parked jets? [duplicate]

While walking around the airport on a windy day I occasionally hear a tingling or rattling noise from the engines of the parked jets. You can see the fans rotating in the breeze. What’s causing the ...
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What are these engine inlet devices used for?

While looking at the Boeing Chinook CH-47 for this question, I noticed the screens in front of the engines, and found similar devices in other photos: Source: left -- right What are these devices ...
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Is starting a jet engine without ground support possible?

We have had more... than... one question about jet aircraft taxiing about the airport without their jet engines running. Those address several issues such as cost vs savings and regulatory approval. ...
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What values can/should be used for the isentropic efficiency of a compressor and turbine?

I was trying to model an turbofan aircraft engine using Matlab and Simulink. In the process I have fixed certain parameters to some specific values which are nominal operating values of the parameters....
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What is the correct equation for rotor solidity?

I'm working in a project that uses"blade solidity ratio", or "rotor solidity", the problem is, there are several articles which defines the equation in a different way changing in the section of the ...
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Are turbine and compressor blades and vanes cast or forged?

I was wondering how blades and vanes are typically made in commercial jet engines. Would you typically use investment casting to make compressor blades or just in the turbine section to accommodate ...
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Is an engine surge classed as an engine fire?

Sometimes flames come out from the exhaust due to bearing distress or turbine blade fracture. Can such flames/fire be considered an engine fire?
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How are turbine blades overhauled?

How are turbine blades overhauled? What techniques are commonly used and how does it affect the integrity of the blade?
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For an electric airplane are propellers the only option for propulsion?

This is for an electric airplane (so no fuels for combustion): Are propellers the only option? Is there a turbine-jet possible with only air intake, electrically compress, and a turbine and nozzle ...
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Would turbine blade twist change if all conditions except the density of the fluid remained the same?

While designing a turbine, the blade twist is apparent from the velocity triangles, and this analysis only depends on the velocity. However, would there be any difference for different media? When ...
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What is the relation between solidity and lift coefficients?

I've seen this graph in a couple of places. I'm not sure what it's supposed to mean, as the formulae I've seen in the papers cannot be found in any standard book or reference. Please let me know if ...
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How are turbine engines started?

What happens to a turbine engine from the time that a start is initiated until stable idle is achieved? What can go wrong?
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Does the stator blade angle changes? Why?

I have read that when jets are on the ground their compression ratio changes. With this change the stator compressor's blade angle changes. Is this true?
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How are fan and compressor discs balanced?

@curious-cat brought up an interesting question on another thread. How are the fan discs, compressor spools and turbines balanced on a jet engine. As they wear they surely get out of balance. Do they ...
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In the compressor characteristic, how do I calculate the minimum flow?

I have a small question, how do I determine the minimum flow point on the compressor characteristic? I.e. what is the safety margin on the curve?
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Where can I get a high-res photo of the RAT from an A320 Airbus?

I'm working on a project regarding the hydraulics system of the A320 airbus. I can't seem to find a clear Hi-resolution image of a grounded A320 with the RAT extended out. Anyone know where I can ...
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In the compressor characteristic, what does this value represent?

$$ ? = \frac{m_t* \sqrt{T_3}}{P_3}$$ All I know is that it is a material property of a turbine, it has something to do with the mach number, and is used for calculating $W_T$. It's kinda similar to ...
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Would it be viable to install a screen in front of jet intakes to prevent them from sucking in birds?

Why isn't there a protective screen with large diameter holes (approx 2') mounted in front of the jet engine intake to protect the turbine blades? This would keep larger birds and large ground debris ...
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What is the efficiency of the turbine of a modern jet engine?

What is the turbine efficiency of a modern jet engine? Just the turbine efficiency only. What percentage of fuel energy the turbine converts into mechanical energy.
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If jet engines did leave chemtrails, wouldn't the chemicals cause adverse reactions in the engines?

Please note, this question does not call into question whether or not the conspiracy theory is true or untrue, but the feasibility of certain chemicals being used as fuel additives in order to make ...
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Compressor-Turbine: Why a shaft and not kind of a “rotating drum”?

I'm studying the fundamentals of jet propulsion and its applications. I really have this next question and haven't found an answer yet: why do jets use a shaft (or more) to connect the turbine(s) to ...
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Are turbine engine reconditioned after severe FOD damage caused by bird strikes?

I've just been watching a video of a 757 suffering a bird strike on take off. The pilots continue with their take off, declare a MAYDAY, shut the engine down and proceed to land without any issues. ...
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I wonder if it's possible to make a “compressed air” turbine engine [closed]

I wonder if it's possible to make an efficient turbine engine that uses only hot compressed air to move but only that, meaning there is no ignition involved. To put it simple can we use compressors ...
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What is the difference between active tip clearance control system and passive tip clearance control system in turbine?

What are the main differences between turbine active tip clearance control system and passive tip clearance control system?
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Is low pressure compressor air used to cool turbine blades?

This photo shows LP cooling air is being used to cool turbine blades. the question is, is it possible to use LP air to cool the turbine blades? would you please guys explain why do they use LP air ...
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What does the term “loading” refers to when we talk about Blade loading and Stage loading in Turbomachinery?

I have been reading about the term Blade Loading and Stage loading in case of Axial Turbines and Compressors, however, I would like to know what does the term "loading" here exactly refers to? What I ...
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Hydro-pneumatic fuel controls and hydro-mechanical fuel controls

What are the advantages and disadvantages of the hydro-pneumatic controls against the hydro-mechanical controls?
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Where is helicopter rotor attached on Allison Model 250 engine?

Which section of the Allison Model 250 engine is attached to helicopter rotor?
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Gas Turbine Engine Starting Sequence [closed]

How to explain the figure above?
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Is this a blisk?

GE Aviation bought the Czech company Walther to get their 600-800shp turboprop engines, now called the H75... On their website, two thirds down the page, the following picture has the caption The H-...
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Why aren’t diesel piston engines used on aircraft like the Saab 340 or L-410?

In contrast to this question (link), I would like to know the opposite - why diesel piston engines aren't used on aircraft with comparable role and configuration to Saab 340, L-410, ATR-42? There's ...
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is boundary-layer jet-turbine a scam?

While exploring open jet turbine designs, I've stumbled upon one CAD drawing which has made me wonder. It is based on a famous Tesla turbine and its highly-efficient way of compressing the fluid. At ...
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Why is the first turbine in a turboprop (or turboshaft) connected to the compressor?

Typically the first turbine after the combustion chamber drives the compressor as shown in this picture. (wikimedia.org) This first turbine spins the fastest and harvests the most energy from the ...
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How many turbine powered aircraft are in the air at any given time? [closed]

I know there are a lot of statistics about how many planes are in the air on average, but not all aircraft flying are turbine-driven. How may turbojet, turbofan, and turboprop aircraft, on average, ...
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What were the J47's turbine blades made of?

What materials were used to make the General Electric J47 turbine blades in the 1960's?
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Would removing heat from the compressor and adding heat to the turbine increase a gas turbine's efficiency?

Since a compressor compresses air, the air temperature increases due to P1/T1=P2/T2. When the temperature is increased it would be harder to compress - so would removing the heat from the air inside ...