The Anonymous Widower

The Mathematics Of A Hydrogen-Powered Freight Locomotive

If we are going to decarbonise the railways in the UK and in many countries of the world, there is a need to replace diesel locomotives with a zero-carbon alternative.

In looking at Airbus’s proposal for hydrogen powered aircraft in ZEROe – Towards The World’s First Zero-Emission Commercial Aircraft, it opened my eyes to the possibilities of powering freight locomotives using gas-turbine engines running on liquid hydrogen.

A Hydrogen-Powered Equivalent Of A Class 68 Locomotive

The Class 68 Locomotive is a modern diesel locomotive used on UK railways.

This is a brief specification

  • It can pull both passenger and freight trains.
  • It has an operating speed of 100 mph.
  • The diesel engine is rated at 2.8 MW
  • It has an electric transmission.
  • It has a 5,000 litre diesel tank.
  • It weighs 85 tonnes.
  • It is 20.5 metres long.

There are thirty-four of these locomotives in service, where some haul passenger trains for Chiltern Railways and TransPennine Express.

Rolls-Royce’s Staggering Development

Staggering is not my word, but that of Paul Stein, who is Rolls-Royce’s Chief Technology Officer.

He used the word in a press release, which I discuss in Our Sustainability Journey.

To electrify aviation, Rolls-Royce has developed a 2.5 MW generator, based on a small gas-turbine engine, which Paul Stein describes like this.

Amongst the many great achievements from E-Fan X has been the generator – about the same size as a beer keg – but producing a staggering 2.5 MW. That’s enough power to supply 2,500 homes and fully represents the pioneering spirit on this project.

This generator is designed for flight and the data sheet for the gas-turbine engine is available on the Internet.

  • It has a weight of under a couple of tonnes compared to the thirteen tonnes of the diesel engine and generator in a Class 68 locomotive.
  • It is almost as powerful as the diesel.
  • It looks to be as frugal, if not more so!
  • Rolls-Royce haven’t said if this gas-turbine can run on aviation biofuel, but as many of Rolls-Royce’s large engines can, I would be very surprised if it couldn’t!

Rolls-Royce’s German subsidiary; MTU is a large producer of rail and maritime diesel engines, so the company has the expertise to customise the generator for rail applications.

Could this generator be modified to run on liquid hydrogen and used to power a Class 68-sized locomotive?

  • The size of the generator must be an advantage.
  • Most gas-turbine engines can be modified to run on natural gas and hydrogen.
  • Its power output is electricity.
  • There’s probably space to fit two engines in a Class 68 locomotive.

In addition, a battery could be added to the transmission to enable regenerative braking to battery, which would increase the efficiency of the locomotive.

Storing Enough Hydrogen

I believe that the hydrogen-powered locomotive should carry as much energy as a Class 68 locomotive.

  • A Class 68 locomotive has a capacity of 5,000 litres of diesel fuel.
  • This will have a mass of 4.19 tonnes.
  • Each kilogram of diesel can produce 47 Mega Joules of energy.
  • This means that full fuel tanks contain 196,695 Mega Joules of energy.
  • Each litre of liquid hydrogen can produce 10.273 Mega Joules of energy

This means that to carry the same amount of energy will need 19,147 litres or 19.15 cubic metres of liquid hydrogen.

  • This could be contained in a cylindrical tank with a diameter of 2 metres and a length of 6 metres.
  • It would also weigh 1.38 tonnes.

The E-Fan-X aircraft project must have worked out how to store, similar amounts of liquid hydrogen.

Note that I used this Energy And Fuel Data Sheet from Birmingham University.

Running On Electrification

As the locomotive would have an electric transmission, there is no reason, why it could not run using both 25 KVAC overhead and 750 VDC third-rail electrification.

This would enable the locomotive to haul trains efficiently on partially electrified routes like between Felixstowe and Leeds.

Hydrogen-Powered Reciprocating Engines

When it comes to diesel engines to power railway locomotives and big trucks, there are few companies bigger than Cummins, which in 2018, turned over nearly 24 billion dollars.

  • A large proportion of this revenue could be at risk, if governments around the world, get serious about decarbonisation.
  • Cummins have not let the worst just happen and in 2019, they acquired Hydrogenics, who are a hydrogen power company, that they now own in an 81/19 partnership with Air Liquide.
  • Could all this expertise and Cummins research combine to produce powerful hydrogen-powered reciprocating engines?
  • Other companies, like ABC and ULEMCo are going this route, to modify existing diesel engines to run on hydrogen or a mixture of hydrogen and diesel.

I believe it is very likely, that Cummins or another company comes up with a solution to decarbonise rail locomotives, based on a conversion of an existing diesel engine.

Refuelling Hydrogen-Powered Rail Locomotives

One of problems with hydrogen-powered trucks and cars, is that there is no nationwide refuelling network providing hydrogen. But railway locomotives and trains usually return to depots at the end of the day for servicing and can be fuelled there.

Conclusion

I feel that there are several routes to a hydrogen-powered railway locomotive and all the components could be fitted into the body of a diesel locomotive the size of a Class 68 locomotive.

Consider.

  • Decarbonising railway locomotives and ships could be a large market.
  • It offers the opportunities of substantial carbon reductions.
  • The small size of the Rolls-Royce 2.5 MW generator must offer advantages.
  • Some current diesel-electric locomotives might be convertible to hydrogen power.

I very much feel that companies like Rolls-Royce and Cummins (and Caterpillar!), will move in and attempt to claim this lucrative worldwide market.

September 25, 2020 Posted by | Hydrogen, Transport | , , , , , , , , , , | 10 Comments

Environmentally-Friendly InterCity 125 Trains

InterCity 125 trains are not the most environmentally-friendly of beasts.

  • They do not meet the modern emission regulations.
  • They still emit a lot of carbon dioxide.
  • They is also a deadline of 2040, when UK railways will be net-carbon-free.

There might also be individuals and groups, who feel that these elderly trains with so much history, should be replaced by modern zero-carbon trains.

  • Would the same groups accept electrification with all the wires?
  • Would the train operating companies, accept battery power will long waits for charging?
  • Would hydrogen be viable on the numerous branch lines in Devon and Cornwall, with some difficult access to depots by road. Especially, if the hydrogen had to be brought from say Bristol or Southampton!

But various engineering solutions are emerging.

Biodiesel

This is probably the simplest solution and I suspect most modern engines can run on biodiesel with simple modifications. InterCity 125s have modern engines from German firm and Rolls-Royce subsidiary; MTU, so they probably have a solution in their tool-box.

Computerisation

I have never built a computer control system for anything, but I did work with the first engineers in the world, who computerised a chemical plant.

They always emphasised, if you could nudge the plant into the best area of operation, you’d have a much more efficient plant, that produced more product from the same amount of feedstock.

At about the same time, aircraft engine manufacturers were developing FADEC or Full Authority Digital Engine Control, which effectively let the engine’s control system take over the engine and do what the pilot had requested. The pilot can take back control, but if FADEC fails, the engine is dead.

But judging by the numbers of jet aircraft, that have engine failures, this scenario can’t be very common, as otherwise the tabloids would be screaming as they did recently over the 737 MAX.

Now, I don’t know whether the MTU 16V4000 R41R engines fitted to the InterCity 125, have an intelligent FADEC to improve their performance or whether they are of an older design.

If you worry about FADEC, when you fly, then read or note these points.

  •  Read the FADEC’s Wikipedia entry.
  • Your car is likely to be heavily computerised.
  • If you took a modern train or bus to the airport, that certainly will have been heavily computerised.

You could be more likely to meet someone with COVID-19 on a flight, than suffer an air-crash, depending on where you travel.

Rolls-Royce’s Staggering Development

Staggering is not my word, but that of Paul Stein, who is Rolls-Royce’s Chief Technology Officer.

He used the word in a press release, which I discuss in Our Sustainability Journey.

To electrify aviation, Rolls-Royce has developed a 2.5 MW generator, based on a small gas-turbine engine, which Paul Stein describes like this.

Amongst the many great achievements from E-Fan X has been the generator – about the same size as a beer keg – but producing a staggering 2.5 MW. That’s enough power to supply 2,500 homes and fully represents the pioneering spirit on this project.

This generator is designed for flight and the data sheet for the gas-turbine engine is available on the Internet.

  • It has a weight of under a couple of tonnes compared to the thirteen tonnes of the diesel engine and generator in a Class 68 locomotive.
  • It is also more powerful than the diesel.
  • It looks to be as frugal, if not more so!
  • Rolls-Royce haven’t said if this gas-turbine can run on aviation biofuel, but as many of Rolls-Royce’s large engines can, I would be very surprised if it couldn’t!

Rolls-Royce’s German subsidiary is a large producer of rail and maritime diesel engines, so the company has the expertise to customise the generator for rail applications.

Conclusion

I think it is possible, that the Class 43 power-cars can be re-engined to make them carbon-neutral.

September 25, 2020 Posted by | Computing, Health, Transport | , , , | 1 Comment

What Size Of Hydrogen Tank Will Be Needed On A ZEROe Turbofan?

I believe that Airbus’s proposed ZEROe Turbofan is designed for the same market segment as a A 320 neo.

  • This aircraft has a fuel capacity of 26,730 litres of kerosene.
  • This will have a mass of 21.38 tonnes.
  • Each kilogram of kerosene can produce 46 Mega Joules of energy
  • This means that full fuel tanks contain 983, 480 Mega Joules of energy.
  • Each litre of liquid hydrogen can produce 10.273 Mega Joules of energy

This means that to carry the same amount of energy will need a 95,734.5 litres or 95.7 cubic metres of liquid hydrogen.

  • This could be contained in a cylindrical tank with a diameter of 4 metres and a length of 7.6 metres.
  • It would also weigh 6.93 tonnes.

As the range of the A 320 neo is given as 6,300 kilometres and that of the ZEROe Turbofan, as just 3,700 kilometres. the tank could probably be shorter.

Note that I used this Energy And Fuel Data Sheet from Birmingham University.

Conclusion

Carrying as much energy as an A 320 neo will be difficult.

  • Range will be reduced.
  • A new more efficient airframe will be necessary.
  • As volume is probably more of a problem than weight, the fuselage might be lengthened by a few metres.

Designing the hydrogen system will be challenging, but I would be surprised if it were an insurmountable problem.

September 25, 2020 Posted by | Energy, Hydrogen, Transport | , , | 5 Comments

Flying A Hydrogen-Powered ZEROe

The ZEROe Turbofan and the ZEROe Turboprop, both have a large liquid hydrogen tank in the rear fuselage.

Will this affect the handling characteristics of the aircraft and make them difficult to fly?

The balance will probably be different as the weight of the tank with a full load of hydrogen could be significant. Think putting two bags of cement in the back of a typical hatchback car.

But all Airbuses should handle the different feel easily.

The three main flight control surfaces, by which pilots control the aircraft; ailerons, elevator and rudder are not actually controlled directly by the pilots, but by computers that are connected between the controls the pilot uses and the control surfaces themselves.

This means that control methods, which are unavailable on an aircraft with traditional controls, can be used to fly the aircraft.

So this means that any problems caused by the heavy weight in the rear of the fuselage can be solved.

 

 

September 25, 2020 Posted by | Computing, Hydrogen, Transport | , , , , , | Leave a comment

Creating Sustainable Aviation Fuels For A Net-Zero Future

The title of this post, is the same as that of this article on Airport Technology.

This is the introductory paragraph.

In June, UK Transport Minister Grant Shapps announced the creation of the Jet Zero Council, which aims to make zero-carbon transatlantic flights a reality within a generation. Dr Neville Hargreaves, vice president at sustainable fuels technology company Velocys and a member of the Jet Zero coalition, explains more.

This paragraph gives a timescale.

“People may think achieving net-zero emissions on long-haul flights, from London to New York on a Dreamliner say, is decades away – it isn’t,” he adds. “We can achieve this in the next five-ten years.”

II suspect, that if all goes well, Dr. Hargreaves is right.

Read the article to find out how Velocys intend to achieve this aim.

 

September 25, 2020 Posted by | Energy, Transport | , , , | Leave a comment

Could An A320 neo Be Rebuilt As A ZEROe Turbofan?

This post is a follow-up to ZEROe – Towards The World’s First Zero-Emission Commercial Aircraft.

I spent a lot of time yesterday, looking at YouTube videos of the following.

  • Airbus A320 aircraft
  • Airbus A 320 neo aircraft
  • Airbus’s proposed ZEROe Turbofan aircraft

I also captured these profiles from the Airbus web site, of three members of the new Airbus A 320 neo family and the current Airbus A 320 ceo.

A 319 neo – Length – 33.84 metres – Max Passengers – 160

A 320 neo – Length 37.57 metres – Max Passengers – 194

A 321 neo – Length 44.51 metres – Max Passengers – 244

A 320 ceo – Length 37.57 – Max Passengers – 180

Note.

  1. The links on each variant lead to Airbus’s on-line specification.
  2. All three variants have a wing-span of 35.8 metres and a height of 11.76 metres.
  3. All variants have sharklets or blended winglets to improve awrodynamic efficiency.
  4. There are different door, cargo door and window layouts on all three variants.
  5. The cockpits, tail and wings look similar.

This capture from an Airbus video, shows the profile of the proposed ZEROe Turbofan.

Note, that the ZEROe Turbofan looks more streamlined than the A 320 neo family, with a redesigned nose and more swept-back tailfin and sharklets.

These are my thoughts on the current A 320 neo family and their relationship with the ZEROe Turbofan.

Focus On Commonality

For each variant on the Airbus web site, there is a section with this title. This is the first sentence for the A 320 neo.

Due to its 95 per cent airframe commonality with the A320ceo (current engine option) version, Airbus’ A320neo jetliner fits seamlessly into existing A320 Family fleets worldwide – which is a key factor for the company’s customers and operators.

Will Airbus follow this philosophy with the ZEROe Turbofan?

If it worked between the changeover between the existing A 320 fleets and the A 320 neo fleets, why change the policy?

The Cockpits

The cockpits of the A 320 neo and the A 320 ceo seem to have a similar profile, but the cockpit of the ZEROe Turbofan seems to have been reprofiled.

In ZEROe – Towards The World’s First Zero-Emission Commercial Aircraft, I showed these front on views of the cockpits of the ZEROe Turboprop and ZEROe Turbofan.

I questioned if the two cockpits were related.

  • A single cockpit for both aircraft would surely ease manufacture, maintenance and pilot training.
  • I’m no aerodynamicist, but it certainly looks that the new cockpit will reduce drag and fuel consumption.

Although the cockpit, appears to be being used in the ZEROe for the first time, I would expect it is already under development and might feature in any later version of the A 320 neo.

The Fuselages

The fuselage width for both the A 320 neo family and the A 320 ceo are all 3.95 metres, with a maximum cabin width of 3.70 metres.

I would expect that the ZEROe Turboprop and the ZEROe Turbofan will also use this width.

Airbus use a design called Cabin-Flex to get the most out of the interior space in the A 320 neo. This paragraph is from the Wikipedia section, that is entitled Cabin-Flex.

By permanently replacing the second door pair in front of the wing (R2/L2) with a new second pair of overwing exits, the capacity of the A321neo is increased from 220 seats to 240 seats and fuel efficiency per seat is increased by 6%, exceeding 20% together with the new engines and the sharklets. The modifications should weigh 100 kg more.[82] Initial A321neos have the A321ceo exit door configuration with four exit door pairs until the Airbus Cabin-Flex (ACF) layout can be selected.

After reading the whole section, it looks to me, that the A 320 neo fuselage is designed, to be all things to all airlines and doors and seats can be arranged to fit any requirements.

In the ZEROe Turbofan, there is a large liquid hydrogen tank behind the rear pressure bulkhead, which could be brought forward a bit to give more space and hydrogen capacity.

I suspect there will be a lot of commonality between the fuselage of the A 320 neo family and that of a ZEROe Turbofan.

I spent a lot of time, as a child building Airfix models of aircraft and it may be too much of a simplification to think of these carbon-composite airliners, as giant Airfix models.

But I wouldn’t be surprised that just like the previous generation of aluminium airliners, they can be remanufactured into something different, just like British Airways Tristars, ended up as tanker-aircraft for the RAF.

I wouldn’t be surprised to find, that later A 320 neo fuselages will be able to be remanufactured into fuselages for ZEROe Turbofans.

Comparing The Fuselages Of The A 320 ceo, A 320 neo And ZEROe Turbofan

These are the three fuselage profiles.

A 320 ceo

A 320 neo

ZEROe Turbofan

Aircraft balance on the wings, which if I remember what little I know about aircraft aerodynamics and design, apply their lift forces to the centre of gravity of the aircraft.

I know that the profile of the ZEROe is to a different scale, but three things are apparent.

  • The windows at the rear don’t go as far back, as they do in the two existing designs. But then there is no need for windows around the hydrogen tank.
  • The hydrogen tank could be as long as a quarter of the length of the fuselage.
  • The front section of the aircraft appears longer.

The longer front section would balance the weight of the hydrogen tank.

The passengers would also help to balance the weight of the tank, by being placed further forward.

There must be the possibility of creating a larger capacity and longer range variant of the ZEROe design, by adding a larger hydrogen tank and further stretching the nose.

Airbus have been stretching these designs for years, so I suspect that they have plans for a large number of possible variants of the ZEROe Turbofan.

According to the Wikipedia entry for the A 320 neo family, there are already five civil versions of the A 320 neo; A 319 neo, A 320 neo, A 321 neo, A 321LR and A 321XLR, plus corporate and military versions.

Add in the Cabin-Flex interior and the various A320s and the ZEROe to come, must be one of the most flexible transport systems in history.

The Tailplanes

As they are of the same height and look similar, the tail sections of the A 320 neo and A 320 ceo families could be almost identical, but the tail section of the ZEROe Turbofan appears to be slightly more swept-back and perhaps more aerodynamic.

As the ZEROe Turbofan, also appears to have had a nose-job, I would suspect that Airbus have a redesigned fuselage in the works to squeeze more fuel-efficiency out of this family of already very frugal aircraft. Could this feature the more aerodynamic tailplane?

Could this advanced fuselage feature in a later version of the A 320 neo?

I also feel, that the functionality of the tailplane on the ZEROe Turbofan will need to be little different to that on the earlier planes.

  • The plane is still powered by two turbofan engines on the wings.
  • Rudder forces, with an engine failure on one side, will still be the same.

The big difference will be that the fuel is at the back of the fuselage rather than in the wings, which will affect the balance.

Will this effect the design of the tailplane? I don’t think it will in a large way, as Airbus seem to have lengthened the nose to compensate.

The Wings

All the wings with sharklets for the A 320 neo family and the A 320 ceo have the same wingspan of 35.8 metres, so I would expect they are all substantially similar.

But there is one big difference in that the wings of the conventionally-powered aircraft are full of fuel.

This would probably mean that much of the wing stresses in the ZEROe Turbofan would be like an A 320 neo flying with little fuel in the wing tanks. As some aircraft in the A320 neo family have fuselage tanks, Airbus can even test the wing forces and handling in a real aircraft.

But it does look that Airbus will have little trouble designing, building and certifying the wing of a ZEROe Turbofan.

There is a minor difference in that the sharklets for the ZEROe Turbofan are more extreme.

But then as I said earlier, is there a new more aerodynamic airframe for the A 320 neo in the works?

Conclusion

I very much feel that there will be a route to convert some or all of the A 320 neo aircraft to hydrogen power.

 

 

September 25, 2020 Posted by | Hydrogen, Transport | , , , , , | 1 Comment