Why a Power Turbine is Needed

Many viewers have asked why the power generated by a turbine engine can't be taken from the main rotor shaft, and why a power turbine is needed. In todays single question episode, I try to answer that.
The video about the MAN MGT6100 is here:
• 3D animation of indust...
It will help you understand what I'm referring to if you watch it.
Please consider becoming participant on my Patreon page:
www.patreon.co...

[@wagsman9999]

At a power plant, they spin the turbine / generator assembly (same shaft) up to speed (say 3600 rpm), then synchronize the generator with the grid using the turbine control valves which admit steam to the turbine (sync check relays are used to verify that voltage, phase, frequency of the generator and grid are the same across the output breakers). When the sync-check relays clear (the generator is sync'd to the electrical grid), the operator closes the output breakers of the generator, and immediately applies additional steam to the turbine so that generator picks up load (you don't want grid motoring the generator - bad). Closing a generator into the electrical grid out of sync is a bad day, the grid always wins as it is an immovable force, it will destroy the turbine/generator.

[@JAMESWUERTELE]

I used to have the voltage slightly higher on the generator before I tie, tie then load and adjust the voltage (balance VARS).

[@C-M-E]

Coincidentally I happened across a vid this weekend that showcased a gargantuan industrial GE 7HA that not only was driven directly off the main/compressor-side shaft to a generator, but was also sandwiched to a steam turbine fed by captured exhaust gas heat on the opposing end of said shaft. If I recall correctly, it was rotating around 3000rpm and producing around 900MW of energy. The scale of the thing blew me away, as just the engine portion was the size of a nuclear-class submarine, not including the array of subsystems around it that took up a factory-sized space. HUGE!!

[@SjaakTrekhaak23]

5:47 1.21 Gigawatts “GREAT SCOTTS”!!!

[@DeliveryMcGee]

To oversimplify, then, the power turbine works like the torque converter in an automatic transmission. Actually that's not oversimplifying, is it? They're exactly the same, a fluid coupling, just one uses a thinner, hotter, less brightly-coloured fluid. Also there are reasonably-sized clutches that can handle 10k hp in Top Fuel drag racing ... that are engaged once, for 3.5 seconds, and then rebuilt if they make it that long (sometimes they come apart and cut the car in half).

[@alecdacyczyn]

Short answer: Because a gas-phase open-cycle torque-converter is easier then a humongous CVT.

[@BrunoEnriquezStruck]

Jay, checkout the Solar Turbines line of Gas Turbines Generator Sets. Many are offered in single shaft (cold end drive) configurations. For example the Titan 130 is a 16.5 MW single shaft genset. Yes, the CED machines have less parts and are less expensive to maintain. Only 3 radial bearings and 1 thrust bearing. In addition the footprint and overall weight is less than 2 shafts machines. The CED turbine exhaust can be axial so it is easier to couple with a downstream boiler for cogen applications. The epicyclic reduction gearbox is an integral part of the CED turbine, the RGB is hard coupled to the rotor. The RGB housing provides structural support. The single shaft (CED) GP turbine has 3 stages vs 2 stages of the 2 shaft version used for mechanical drive applications. The compressor is the same on both: 14 stages, 19:1 PR but the guide vanes and bleed valve are controlled very differently since the CED rotor always rotates at the same speed (100% Ngp) even at idle and part load.

[@slkgeothermal]

Jay sorry about the winter thing sneaking up on you :-) Everyone, I urge you to sign up for Patreon to support what this man does for the community and be an insider on what it takes to make a turbine engine work. Plus he has some pretty comical insights to things. His videos are not just fired from the hip and then posted, these things take time to produce and edit. $5 dollars a month is cheap at twice the price for what you will receive. Thank you Jay

[@KronosIV]

Yes, it is worth every penny. I'm not sure if he'd like me to say this but I think he's a great teacher too.

[@boomer9900]

I learn something new every time you post a video. Thanks. A few days ago I was watching a video about Musk's Raptor rocket engine. With all the ferociousness coming out the bell of that engine, the pressure at the exit is at or below the air pressure on the ground. This velocity and pressure thing is something you need to really wrap your mind around.

[@MDKSMD18]

There's a company called Solar Turbines that makes many turbines that are single shaft turbines used for power generation. Centaur 40, 50, Taurus 60, 70, and Titan 130 all have single shaft turbines. They also make two shafts off all those engines for use in driving pumps/compressors

[@perrydiddle3698]

Exactly. Spool up the turbine and generator, and sync the phases to the grid, then switch over. And, if it’s a Cogeneration unit, be prepared to handle the sudden production of steam (with vents, switching from electric motor driven pumps to turbine driven pumps, and line up other steam consumers (fractionating columns, heaters, etc.)

[@johncasor9698]

winter now ??? 100 all week in san diego ??? Nov 1ST is when it starts to get cold at night here... and this is another Great video. thx a bunch..

[@merlepatterson]

A free wheeling (stripped) generator, driven only by the power turbine gearing, can be spun up to match frequency of the grid power and then the breakers are typically connected (paralleled) at about 5 degrees before phase synch TDC using a synchroscope. Then the load is taken up by increasing generator (throttle) RPM, but since the RPM can't overcome the grid power generators RPM (frequency) the current (load) increases on the generator creating more horsepower torque, rather than a frequency increase. At that point, I would think EGT monitoring comes into play for monitoring turbine load capacity.

[@JAMESWUERTELE]

We hit T48 at 1630 and that’s all the load we get. LMS 6000 at 4860 ft. 40-41.5 mw.

[@merlepatterson]

@@JAMESWUERTELE Yes. There are so many different configurations of turbine/generator types (Steam, Gas, large, small), that one has to try to just break it down into theory of operation blocks.

[@merlepatterson]

@@JAMESWUERTELE Most importantly, "The biggest generators rule the frequency department when in parallel"

[@otp_dagger3-366]

Thanks for the nice video, I have always asked myself this question

[@keithm8715]

Let me clarify by stating that all of the aero derivative gas turbine electrical genrating stations I have worked at use power turbines, but these are extremely ineffecient, and operators avoid using them for main grid power supply. There is a manufacturer that makes single shaft combined cycle power generation station. That's right, one shaft for the gas turbine, steam turbine and generator. This unit spins at 3600rpm , except the high pressure steam turbine which spins at , 8000 rpm. There is a massive clutch between the steam section and the generator/gas turbine. Now that I think of it, most of the gas turbine power plants I have worked at have a directly coupled gas turbine and generator. This allows the operator to start the gas turbine with grid power using the generator as a starter motor. These spin at 3600 rom and have no clutch. The steam section ( for combined cycle plants) are completely separate with their own generator. These ARE NOT aero derivative plants, and produce upwards of 200 megawatt per unit.

[@JAMESWUERTELE]

Keith m I run LM100’s (2), and 5 LMS 6000 pf ‘s. The 100’s generator are not coupled to the gas generator, on;y using a power turbine. We use the hydraulic starter to start the units. The 100’s are 46 percent efficient, even as a simple cycle.

[@robu101]

Yay! Another video!!! Watching it as we speak. Thanks AgentJayZ.

[@mtnbiker310]

As far as clutches go, I understand the F-35B uses a clutch to transfer power from the engine to the lift fan. It's not power to the electrical grid, and it is expensive, but it is a clutch. Thanks for your videos!

[@AgentJayZ]

Yeah, pick the one example that is: Really not relevant to the original question... Proves my point about complexity being expensive... Is used by the most overbudget project in all of human history...

[@failranch9542]

Good explanation AgentJayZ but the Italian was on to something. For electric power generation you don't necessarily need a multi shaft engine. Look at a Frame 7 or Frame 9 Heavy Duty GE engine. Single shaft. The power turbine and compressor and driven generator are all on the same shaft. But these only make power at one speed: 3600 rpm on 60 hertz systems (7 Frame) and 3000 rpm on 50 Hz systems (9 Frame). I would imagine that these would be pretty horrible at powering something where we needed power at multiple rpm's like in a ship. That's where a gas generator / power turbine makes sense. Edit: you spoke to that a bit. I didn't watch far enough :-)

[@JAMESWUERTELE]

I run two LMS100’s, they are a 100 mw GE simple Cycle gas turbine generator, we have a big multi stage power turbine, coupled to a Brush brushless generator. At the altitude it’s at we usually get 94 mw net.

[@thenewhalogod]

You CAN take the power from the rotor shaft directly, look at the MU-2, however it is vastly better to have a power turbine, so you can't stall the engine out with the prop.

[@charlottejet4338]

Simplicity, efficiency & ease of maintenance? Thanks for sharing another great video.

[@marlibread]

3 weeks... i was wondering how long after the videos are uploaded. Love your videos....👍👏👏👏👏

[@oisiaa]

The F-35B uses a clutch to engage the lift fan. I believe it's around 20,000shp and the clutch has about 200 engagements before it needs to be replaced/overhauled. I think it engages at a relatively low load though (with closed inlet guide vanes).

[@AgentJayZ]

200 flights... and what was the price for that fan clutch inspection overhaul? I believe I used the word expensive somewhere in there...

[@guyh3403]

Thanks for the detailed explanations. They're appreciated.

[@minetdbrogs9386]

I didnt do calculations about exact power generation costs...but isnt it cheaper to produce electrical power say above > 1 megawatts of electricity using gaz turbine engine rather that using diesel engines say each 250 kw unit power generators...over long term 5 yrs +

[@AgentJayZ]

Yes, it is cheaper. It's even less expensive to use coal to boil water to feed huge steam turbines. That's how most american power is produced.

[@matthewdupuis232]

For the industrial powerplant the power turbine design sure makes sense, but Garrett/Honeywell has done quite well with the TPE-331 engines which are a single shaft turboprop. A completely different set of requirements, but at least in the 1000-1500 hp aerospace application the gearbox seems acceptably light, cheap, and maintenance-free.

[@racerroy1]

Hi there dude, hope your keeping well. I just watched a video from a past pilot of the SR71 amazing aircraft it is, have you ever worked on the jet engine they use in this aircraft ? Pratt & Witney.

[@AgentJayZ]

The J58 no longer has any use, anywhere but in a museum.

[@My-Opinion-Doesnt-Matter]

5:47 What the hell is a gigawatt? XD Btw, it actually exists - SSS Clutch: kzbin.info/www/bejne/n3KUoGmXf8qbd8k The highest power SSS Clutch transmits 320MW at 3000rpm. The highest torque SSS Clutch transmits 4MNm at 600rpm. The highest speed SSS Clutch rotates at 16 000 rpm www.sssclutch.com/en/about/ It's not a friction clutch, so 4:20 it won't burn out: "The SSS Clutch can continuously operate engaged or overrunning at maximum speed without wear occurring." www.sssclutch.com/en/how-it-works/ Small error @ 26:04 1200 hp ~ 0.9 MW

[@AlessandroGenTLe]

LoL, this was exactly my question last time ;) TL is because my nick was created after I've read Imajica from Clive Barker (the starring was a guy named "Gentle") and because I firstly used it into a motorcycle forum, and my bike was (and still is after 23 years) this exact TL1000S here: bikez.com/motorcycles/suzuki_tl_1000_s_1997.php Thanks for the explanation Jay!

[@AgentJayZ]

Nice machine. I rode and raced an SV 650. Favourite bike of all.

[@garykusnierz2108]

Ok MR. back to the future great info as. Always

[@perrydiddle3698]

I don’t know squat about power generation from jet engines. Oops. Gas turbine engines. But, in the cogeneration at the oil refinery I worked at, I know the generator was linked to the compressor shaft at the front of the engine. Then, the natural flow of compressed air, combustion chamber, turbine exhausted into an economizer, (preheating Boiler Feed-water) then onto remaining boiler feed-water heat exchangers to generate steam. As far as utility power plants, I can only imagine the steam is used to drive turbine driven BFPs and lube oil pumps, cooling water pumps, etc. but, I couldn’t say for sure. Looking at Google Earth, the 4 coven units (for back up to the two main oil fed boilers) I cannot determine where the steam production goes at the Los Angeles Department of Water & Power.

[@mr48chevy1]

Also should mention the Allison 501 generator (T56 aeroderivative) which is a direct drive generator used on ships. Gearbox drives the generator rather than a prop on an aircraft

[@AgentJayZ]

If it has a gearbox, it isn't direct drive. Perhaps we are using different definitions.

[@roflchopter11]

4:37 if the generator is actually connected to the grid, it's spinning at synchronous speed. Unless you're trying to dark start the grid, in which case you probably aren't using a gas turbine. Now, connecting a huge generator to the grid is its own problem... Here's a question: if reduction gearboxes aren't worth it from a maintenance and efficiency standpoint, why are we seeing geared turbofans?

[@AgentJayZ]

Yes! Geared turbofans are a great idea.. they save a separate turbine. But oh, that gearbox! High speed, High torque... high cost and high maintenance. Personally I don't like the idea, but the Garrett TFE 731 geared turbofan has been quite successful for the past 40 years.

[@StringerNews1]

A lot of times there's not much difference between a motor and generator, and they can be used for both purposes. IME gas turbines that are on the grid are used for short demand peak capacity, so they need to come online fast and shut down easy after only a few hours operation. With the grid already energized, grid power could overcome inertia by feeding back EMF to the generator. That way the power turbine could be up to speed before the gas generator reaches full output, and back EMF would keep the generator synchronized with the grid. No clutch needed.

[@ASJC27]

With very high bypass ratios, the optimum rpm for the core LP shaft and the fan's is very different. In this case it is beneficial to use a geared fan to allow both to operate at their efficiency peaks. This more than compensates for the small power loss through the box. Without a gearbox, such a high bypass engine would require more LP stages, at both the turbine and the compressor side. This will reduce the LP compressor's and LP turbine's isentropic efficiency (wasting power), and increase engine length (and weight). The end result is an engine that may have better propulsive efficiency (courtesy of its high bypass), but worse thermal efficiency. Overall efficiency depends on both thermal and propulsive efficiency, so you can't just improve one at a blind cost to the other, and the limit in a traditional configuration is the difference in tip speeds of the fan and LP assembly. This is also the motivation behind RR's triple shaft engines, but this can only be pushed so much - with even higher bypass ratios a geared fan is the only practical solution.

[@StringerNews1]

@@ASJC27 I'd think with fan blade radius increasing every year that keeping the blade tips from going supersonic would be a hard limit too. Even if you could get efficiency, the noise would not be compatible with passenger planes.

[@ASJC27]

@@StringerNews1 As the fan's tips become transonic, its efficiency drops very quickly. Therefore designing for peak efficiency will also have the effect of avoiding a supersonic tip. Most turbofans have a supersonic tip at take off thrust (when efficiency is not the primary concern) but are subsonic at cruise setting.

[@777.productions8]

hey i love your content, not the first but still glad I caught you

[@namibjDerEchte]

Always informative. I've got a question: are you aware of any high-altitude (= high compression ratio) intercooler turbine systems or devices that could serve as donors for the difficult (compressor+turbine) parts of such a system? I'm currently doing technical feasibility research for a ~500 kW (electric) hydrogen fuel cell plane, but aerodynamic efficiency dictates a large wing aspect ratio and having the wings thick enough to put (almost) everything inside of them, including pilots. At the weight limits for what doesn't yet count as a heavy aircraft (with the onerous regulations around them), optimal cruise would end up around 30~40 km, where the air density is just 0.3 ~ 1.5% of that at sea level. I found industrial multi-stage radial compressor systems listed to cover what looks like the right airflow range, but I think they'd be heavier than desired. If needed, I'd easily be able to accommodate a 2 m diameter and up to ~ 2 m length low-pressure compressor that takes this outside air and delivers 10~20 % sea level density to the high-pressure compressors that need to feed their fuel cells with 200~300 % sea level density air. But the air needs to be relatively cold, below 100 C. It would be nice to recover the energy in the steam-laden exhaust that could be extracted by condensing the steam, if there's an aircraft-suitable turbine that would survive the condensation. I'm hoping you might be able to point me to some information/names-to-search, so that I can continue my quest on the search for a plane more than twice as efficient as what's currently being brought to market (there are compromises associated with this, as you might imagine).

[@sheep1ewe]

That sounds realy interesting!

[@diesistkeinname795]

You could do something like Grob did with the Stratos, use a gas generator from a turbine engine used as a 1st stage turbocharger before the 2nd stage turbochargers. However I don't think it's worth it with such low temperature difference. Especialy using water wouldn't be efficient at all as it requires you to carry a lot of it. However you could try a stirling engine, peltier elements or an a steam engine using a fluid with a lower boiling point such as propane. Be it a steam turbine or a piston based system, but in a closed system with a condenser exposed to the outside air and the boiler beeing a heat exchanger that cools down the compressed air. At -30 to -50 °C outside temperature and 50°C temperature of the compressed air leaving the heat exchanger, you would have 80-100 Kelvin or with a counter flow heat exchanger 130-150 Kelvin temperature difference, wich could be usefull. (More like 100 Kelvin due to non-perfect heat exchangers)

[@namibjDerEchte]

@@diesistkeinname795 I think you miss-understood. It's a hydrogen fuel cell, that has an air inlet and an air outlet, and the outlet is a bit warmer (10~20 K) and has more water. I need to recover the exhaust pressure's energy to have any good efficiency, because the power to compress the intake air would be about 40% of the electric output. But all of that, and a bit more, is contained in the exhaust and could be extracted by a turbine. I know about the statos, but they could handle much hotter intake air, I think, and they needed much less compression ratio from the turbocharging setup. Hence the question regarding where one might find large aero-suitable radial compressors. Industry uses them for generating pressures of a couple hundred atmospheres, but those are obviously made to handle far denser air then what I'd have.

[@JohnWilliams-dd7up]

Bernoulli's principle can help you out with explaining things Mr. JayZ. Basically what is going on with the jet engine it's trying to move the same quality of air through entirety of the engine at different points. Since the engine is a steady flow rate the velocity has to change to accommodate for the different areas in the engine. You're also converting air pressure to velocity and vice versa. Another words as air pressure increases, velocity decreases and as pressure decreases, velocity increases. So you're converting the pressure in the combustion part in the turbine to air velocity out the back.

[@AgentJayZ]

John, that is not really correct. Combustion heat does not increase the pressure of the gases. This is the most common misconception, so don't feel bad. The heat causes massive expansion, and it is this huge increase in volume that causes the exhaust gases to rush out of the combustors at high speed. The pressure that was created by the compressor is then converted into torque by the turbine, and the residual pressure after that... combined with the high speed... is further accelerated to an even higher speed of the exhaust gases as they pass through the final accelerating nozzle, creating the propulsive "jet" which gives these engines their name. Combustor pressure, in the presence of the heat of combustion... is less than compressor discharge pressure.

[@jameslleary]

1.21 gigawatts!!!! 1 point 21 GIGGAWATTS!!!!! Tom, what was I thinking???!!!!

[@lycossurfer8851]

@4:18. So a 4 puck cable clutch maybe?? 😄 Just take the one off of a motorcycle since the weather got cold

[@unclemonster48]

Idk if you’ve ever been to sowega ga but they have gas turbines at a power substation. Company I work for takes care of the centrifugal chillers there. Always thought it would be cool to bump into you on a jobsite someday. I was wondering about your thoughts on Union Pacific’s jet turbine locomotives.

[@AgentJayZ]

There are some good DVDs out there on those trains. I was a bit disappointed to find out that the sound is all Foley-ized, and they used the sound of an idling turbine engine for every shot.

[@zapfanzapfan]

The free power turbine on that German engine has two stages but the single shaft version only has one extra turbine stage. Maybe that caused the drop in efficiency?

[@0jimmypiffpaff0]

😎 ! thanks for the proper explanation! Keep up the good work! Cheers!

[@nhzxboi]

When connected to the grid the generator will either drive(making money) or be driven(losing money). Many, I think, do not understand that. Is true with any power plant.

[@JAMESWUERTELE]

nhzxboi you never run a generator as a motor. I have heard of using old generators as a condensing unit. If we motor a unit, 52g doesn’t open, the protection relays will clear the yard through the next level of protection. Making a bad day of restoration.

[@GTI18tvw]

To protect turbine, there is reverse power protection in the event were the gas turbine stops producing forward power. With 52G breakers open the generator is also used as a motor to start up the turbine. A separate variable frequency drive system will bring the turbine to about 50% of idle speed then turbine can be started. Once the fuel is ignited the starting system shutoff and the turbine is to brought to idle speed.

[@nhzxboi]

@@JAMESWUERTELE No, you wouldn't but, it would "want" to run that way if no synched. Keep the synchroscope in the middle.

[@JAMESWUERTELE]

@@nhzxboi that’s almost impossible, you have sync relays and you cannot close a breaker on a out of phase generator, it has happened at a plant I worked at due to an old air breaker, it rocked the building, the generator never sounded the same. Loosened all the wedging.

[@nhzxboi]

@@JAMESWUERTELE Certainly is possible. Especially with smaller systems. More likely to blow the breakers but if you are 'just a little' bit off, it is mechanically violent. Very thin line between the two.

[@NoIdeaBrother]

I wish Covid was summer too

[@turbofanlover]

I'm full. Thanks again, Mr. "Zulu". :)

[@BaldSasquatch]

It might just be translation of terminology, but would a simpler way of thinking of a power turbine be that it "converts" one form of energy into another? It's converting pressure generation energy (gas generator) into rotational energy (power turbine torque). No magical gain, minimal frictional loss (compared to a gear reduction), and the ability to "decouple" the power turbine from the spinning has generator. Am I correct in thinking this?

[@CertifiedIndustryProfessional]

Well really the turbine is generating rotational force which is also what’s required by our output load so it’s not really a conversion as such. Separating the power shaft from the load shaft let’s you finely control the power of the engine and the speed of the output. Think about a turboprop aircraft flying at maximum altitude - the engine is held at maximum continuous thrust, but the prop speed is reduced down to an efficient cruising RPM. It’s not always desirable to have the engine RPM to relate to the output RPM.

[@jamesturner2126]

AgentJZ, PLEASE expand your videos into turbine-superchargers and piston aircraft engines. You are more than qualified to speak on these. You could maybe get 10 videos, and open up your appeal to auto technicians. I'm an auto technician. Just an idea.

[@imagiro1]

Hi AgentJayZ! Thanks for the video! Just a question: Of course I watched the video about the MGT6x00, and I noticed, it does not have an annual combustion chamber. Somehow I thought, they are meanwhile state of the art? So I wonder, what might be the advantage of an - uhm - linear combustion chamber? Is it just the simpler design?

[@AgentJayZ]

It has a strange arrangement of what look exactly to be Dry Low Emissions combustors. These things were developed for cleaner burning of fuel in aeroderivative engines. They allow for a longer combustion pathway, without lengthening the engine, which would require some very expensive changes to the shafts and cases. This being a new industrial design, maybe they decided to go with proven tech... stuff that works, instead of designing a longer engine with longer combustion pathways. It is always really expensive to start from scratch, instead of building upon what is already working well.

[@imagiro1]

I see - thank you for the explanation!

[@sheep1ewe]

Thank You for uploading! (Actual first)

[@perrydiddle3698]

What’s your practice on reusing or replacing nuts and bolts? Any concerns that the threads won’t be able to handle the torque? I don’t know if torque is the correct term to use when you’re looking at just linear failure and not twisting failure.

[@AgentJayZ]

All undamaged fasteners are reusable, unless listed in the overhaul manual as single use. Undamaged.

[@thisisyourcaptainspeaking2259]

I'll ask if you'd want to use a clutch, then why not use a reciprocating engine as well?

[@vaishnavichoudhary5850]

Sir Jet Engine Blades And Combustor are Made up of which Metal

[@AgentJayZ]

Both are made from alloys, which are a mixture of metals. The exact recipe for each is not available to me.

[@JoshuaRinaldi]

merry christmas sir.

[@lSunTzu]

I'm a mechanical engineering student. I've been searching for jet engines and when I looked at the books you suggested, I couldn't find some of them. I want to ask because I learn better with videos. Are you planning to prepare a detailed and long-lasting video training about gas turbine engines? I could not find books such as the Jet-Engine Fundamentals. Would you recommend other alternative books and new ones?

[@AgentJayZ]

A video course is a possibility if I can generate enough support for it. Otherwise, "the Jet Engine" by Rolls Royce is an excellent book with fantastic diagrams. Somebody found a free copy of it available online. Wasn't me, and of course I can't post a link. But any engineering student should have no problems with those small obstacles, eh?

[@lSunTzu]

@@AgentJayZ I found the book you mentioned. I am working from the Rols Roys book. I found it in the first book in the video you recommended the book. only second, I couldn't find the book you suggested. I will participate in the 39 video training on your site if it helps engineering students. Thank you very much for your answer.

[@pey-yote]

I always thought of the power turbine as a “pneumatic” torque converter. But i use language that makes engineers cringe😂

[@GeofreySanders]

"aerokinetic"

[@3SPR1T]

Isn't the energy that you bring up to compress the gas in any engine, let it be jet or piston, getting won back in the next stage? Consider a 100% ideal combustion engine with no fuel and spark. When you rotate the crankshaft and compress the air, that air expanding in the power stroke will provide the same energy as you put in the compression stroke. And with the engine running you get the energy from the compressed gas back (no blowby) + the energy from the air fuel mix. So a 300hp engine won't produce 900 internally. So compression and expansion without fuel is a net 0 energy factor in an ideal environment.

[@laird2k2]

Well a) real engines aren't close to ideal and b) compression isn't the only loss. Cylinder friction, shaft friction, various pumps and pressure they work against.

[@3SPR1T]

@@laird2k2 But we are solely talking about the compression. I made the system a Ideal condition to make it easier to understand. In the real world you loose energy if you do anything, but that's not the point.

[@ASJC27]

@@3SPR1T Yes, the energy that's consumed by the compressor in a jet or by the compression stroke in a piston is contained within the gas and doesn't go to waste. Your example of the cylinder compression is also how cylinder deactivation works. In such engines the valves of the deactivated cylinders remain close and fuel isn't injected. They are effectively turned into an air spring where nearly all of the energy they consume in the piston's upstroke is released again in the downstroke. However, a 300 hp piston engine really releases about 900 hp as it burns fuel. That's because most piston engines are around 30% efficient, so about a third of the energy becomes useful power, about a third is expelled as heat through the exhaust, and the final third is expelled as heat through the radiator. Note that nowhere is the compression energy wasted in that balance. The same with a jet. The power consumed by the compressor is put into the air, then after combustion the same amount of power is extracted by the turbine driving the compressor and being put back into the air. It doesn't go to waste. In both a piston engine and a gas turbine (as well as any other type of heat engine) losses are mostly inherent to the thermodynamic cycle. Improving thermodynamic efficiency requires higher compression, in both a piston and a gas turbine.

[@AgentJayZ]

Sorry, I won't go down the rabbit hole of theoretical thermodynamics. That's more for the arguments department, to the left, at the end of the hall...

[@roybm3124]

On land based machines almost always a steam boiler is built behind the gasturbine using the hot exhaust gases. These hot gasses are ramped up with external gas/oil burners inside the boiler. With water pre-heaters built into the boiler exhaust the gasses are leaving with +/- 130 C.

[@patjohn775]

Turbine engines are very expensive is there a junk yard or surplus auction where an old unreliable engine can be found cheap for someone who just wants to tinker and learn

[@AgentJayZ]

There are junkyards where scrap engines can be found. Usually they are large and expensive to move. Tinkering is one way to learn. But often specialized tools or procedures are needed. As a minimum for disassembly without destruction, you will need the appropriate overhaul manual for whatever engine you find, a crane with 2 hoists for turning it vertical, And a great deal of patience. A fairly good approximation of what you're considering is documented on my Patreon channel. Keep in mind I've done this many times, and have some tooling built. I wish you luck and patience in your adventure.

[@patjohn775]

AgentJayZ I’ll check out your Patreon. I’ve the normal machine shop tools in my barn (southbend lathe, bridgeport mill, welders, 3 ton crane, etc.). I was hoping to start with a smaller engine; like something from a military generator. I wish there was a place like yours near me where I could volunteer and learn from a master. I’m a software engineer by profession but I can’t sleep at unless I’m working with my hands. It’s a bit of a sickness for me 😅

[@AgentJayZ]

Step 1) Find a small engine or APU Step 2) Obtain the overhaul manual for the engine Step 3) Follow the instructions. Note: failure is guaranteed without step 2.

[@jamesturner2126]

7:05 Pense incident! XD 😆🤣💀

[@bccev770]

Ace!!

[@davidyisrael007]

I cant believe how small that main shaft is.

[@sean69200]

i would like to know how are you doing building avro engine you have inyour sea cans

[@leadsled8961]

pressure is the resistance to the flow.

[@AgentJayZ]

Actually, resistance is resistance. Pressure increases upstream of a resistance to flow.

[@dragancrnogorac3851]

MAN video claims that single shaft turbine is more efficient, cheaper and cheaper to maintain. Quite interesting. Seems like meanwhile someone cracked the code for huge gearbox. I bet there is 50 kw power used only to lubricate and cool gearbox

[@paul1e]

No mb rides after next week in finland either😯

[@AgentJayZ]

I believe Itchy Boots is there right now...

[@paul1e]

@@AgentJayZ kinda yes :D

[@gersongomes9925]

please activate the subtitle and the translator, thanks.

[@AgentJayZ]

No. As explained before, the translator and the subtitle generator does a terrible job, making the information I am trying to share inaccurate and useless.

[@WarblesOnALot]

@@AgentJayZ G'day... Excellent answer. "The Computer is too stupid to handle the Jet-Tech-Glish (Jet Technichal English)...; BECAUSE nobody who writes Translation Programs actually underconstumbles Jet Engines..., and nobody who disassembles, inspects, replaces Parts, & reassembles Jet Engines writes Programs for Electromechanical Silicon Brain-Substitutes to correlate Languages spoken in Realtime. To better comprehend why that is so..., look into the second half of Robert M. Pirsig's book, "Zen and the Art of Motorcycle Maintenance" ; whereinat he explains what occurrs when the ArtyFartyGlitterati attempt to write Technical Manuals. Just(ifiably ?) sayin', Such is Life. Have a good one... Stay safe. ;-p Ciao !

[@TheDefeatest]

first few seconds I'm like.....jeeeeezzzzzusssss!

[@Abhisheksharma-lx9ur]

I want to know that why turbines stages are always less than compressor stages?

[@AgentJayZ]

It has a lot to do with the fact that, even though the two devices have very similar appearance, they perform completely different functions.

[@ASJC27]

In a compressor pressure increases progressively as the air passes through it. In aerodynamics this is known as an adverse pressure gradient because it promotes flow separation on the airfoil, leading to a stall. In a turbine this is reversed - the pressure gradient delays separation. As a result, a turbine blade can use very aggressive airfoil designs while the compressor can't. Visually, if you look at a turbine blade's airfoil, it is thick and highly cambered ("banana" like). A compressor blade's airfoil is relatively thin and lightly cambered. The end result is that a single turbine stage can have a much greater turning of the flow (internally) and therefore extract much more power than a single compressor stage.

[@darkmath100]

You could make a motorcycle with a power turbine to help keep the rain and snow off you. Hang in there AgentJayZ.

[@mwan200]

Can you use methane to power a gas turbine for power production .

[@AgentJayZ]

It's one of the very best fuels to use.

[@patricksworkshop6010]

@Joe Milosch probably, hydrogen gas is just not found in large quantites underground, i think the turbine fuel system would have to be updated as hydrogen flames are different than hydrocarbon

[@patricksworkshop6010]

@Joe Milosch possibly, i think that just using solar panels would be alot more efficient and easier to store than large quantities of hydrogen gas

[@AndreaBorgia]

1.21 .... :D

[@injlabs]

I viewed another MAN video that show an axial compressor feeding a large centrifugal compressor (intercooler in-between) that appears to be a single shaft. kzbin.info/www/bejne/raOYZ2Wlr9eGkNk I didn't think you could not turn a centrifugal compressor at the same speed as the axial. Especially at that diameter?

[@AgentJayZ]

The two look roughly similar in diameter, so it would work mechanically. I'm sure the engineers matched it up aerodynamically to be very reliable. It might look funny, because the centrifugal is not pumping ambient air, but the much denser, cooled output of the axial compressor.. The PT6 turboprop has an axial booster feeding a centrifugal compressor, and they are all mounted on the same shaft. A much smaller machine than this one!

[@raimo5091]

Patreons help to keep your shop open? I thought you had a commercial operation going there not a charity hobby shop.

[@AgentJayZ]

It's not a charity hobby shop. Any source of income is helpful in these messed up times.

[@raimo5091]

@@AgentJayZ Ah yes, my appologies. I keep forgetting about that dreadded virus.

[@steveegbert7429]

@@raimo5091 It may be that Patreon helps pay for the time that Jay puts in to making AND editing these videos, when he could be spending that time sleeping, eating, or spending said precious time with loved ones.

[@TeemarkConvair]

@@steveegbert7429 for sure. the range varies a LOT but he could be spending around 30 minutes for one minute of final video. software's not cheap, and, the pc/MAC, and then, as mentioned, his actual, sit and fiddle, time. well worth our support.

[@CDhn455]

Do you have a Minnesota state flag on your wall of flags yet? I can send you one if you don't.

[@AgentJayZ]

Not yet. I was in Minnesota in Summer 2019. Very nice people!

[@CDhn455]

@@AgentJayZ Awesome!! Just let me what size will fit best on your wall and the address to send it to, and I'll get you one.

Lmao. What stupid question for the guy that is from 5 hours from Milan... Anyway thx for explaining

[@AlessandroGenTLe]

Yeah Bellini, such stupid question that there are turbogas engines that work in that exact way as shown from Jay himself. Repeat with me "there are no stupid questions, only eventually stupid answers" (oh, and people so selfish not to understand this). And by the way, it's not 5hr from Milan. Rome is 5hr from Milan.

[@AgentJayZ]

Easy now, boys: Z is being closely monitored for any further douchebaggery... Alex, you have achieved distinguished status, and it has been shown over the years that it often leads to jealousy. Best thing you can do is avoid feeding the trolls...

[@AlessandroGenTLe]

@@AgentJayZ wise words Jay. Sorry, my Italian temper sometimes takes over :)