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#151 2021-01-14 20:10:35

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Internal combustion engines for Mars

Subaru engine is going back together slowly over the past few days after cleaning up the head surface that was at touch one could feel dents and none flush conditions across the flat areas. Had to also clean up the block surfaces as the metal from the failed gasket had adhered to the its surface making it such that it would not mate up flush as a flat surface to the head. The head held true so no milling was required for warpage. Used several grit sizes in cleaning up both surfaces with a rubber flat surface adhered to a flat metal plate to hold the sand like paper in place while doing it by hand. Used wet wipes to clean the cylinders after putting several inside them to pick up the paper particles and made sure that there was nothing there to score the walls. This was done over several days last week.

Placed the new 3 layer gaskets onto the block in the correct position and placed the heads onto the block where it was then seated with the bolts and cinched up tight by hand so as to bring the pressure onto the head gasket block assembly to remove the gaps over night. The following day I cinch it up further with the bolt sequence pattern with the first level torqueing instruction followed by the next day a continued setting of the max torque required.

Had finished with the intake manifold mounting going back onto the heads as the final thing making the electrical connection before breaking for the night.

Today I confirmed that the max torque was still unchanged as sometimes you have stretch as they temperature cycle.

I got one of the head covers back into place and put the ac compressor into its location as well. Of course the other head cover will go on tomorrow after work when I stop by to work on the engine.

The to due list is getting smaller for the rebuild. Still need to mount the timing belt, tensioner pulley ensure the timing marks are aligned before doing the final fit of the cover for the belt. Will need to purchase a new thermostat, a change of oil, new coolant, a new replacement oil filter for when the engine gets put back into the car. Once the engine is in the exhaust will be put back in and the radiator fan assembly before filling it with the much needed fluids.

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#152 2021-01-15 06:04:59

tahanson43206
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Registered: 2018-04-27
Posts: 7,680

Re: Internal combustion engines for Mars

For SpaceNut re #151

Thanks for this detailed update on your repair of the Subaru engine! 

As you work on this system, can you imagine doing the same on Mars, with the complication of restricted supply of materials?

The folks over in the electric power topic are going to have to perform maintenance on their equipment as well, albeit less frequently.

Electric equipment runs so long folks may forget how to maintain it.  That's a non-trivial complication, and it's why I keep bringing up the need for planning for training and skills exercise. 

(th)

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#153 2021-01-15 20:17:58

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Internal combustion engines for Mars

I was remined of the fact that we have a seasonal methane release that if we find the vein where its coming out that we have another source of fuel that would have very low embodied energy to gather for the engines use.
No work again on the engine until Tuesday next week for the reassembly and use once its reinstalled into the vehicle.

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#154 2021-01-15 20:18:15

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,625
Website

Re: Internal combustion engines for Mars

A reminder:  spark ignition is generally associated with compression of premixed fuel-and-air,  and absolutely with lower compression ratios (4 to at most 11),  and with higher autoignition temperatures (high octane,  low cetane). 

Compression ignition is pretty much restricted to compression of dry air with injection of fuel after compression,  absolutely with high compression ratios (8+ to almost 30,  and absolutely with low autoignition temperatures (low octane,  high cetane). 

You cannot ignore those kinds of physics and physical chemistries.

GW

Last edited by GW Johnson (2021-01-15 20:18:31)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#155 2021-01-15 20:46:57

tahanson43206
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Registered: 2018-04-27
Posts: 7,680

Re: Internal combustion engines for Mars

SearchTerm:Spark Ignition GW Johnson http://newmars.com/forums/viewtopic.php … 94#p175894
SearchTerm:Compression Ignition
SearchTerm:Ignition

For GW Johnson re #154

Somewhere along the line this topic may be lucky enough to land a design that is optimized for all the factors that are in play on Mars.

There are trades involving the fuel (CO/O2-CO2), the materials of which the engine components are made (locally sourced), the manufacturing process, the education, training and experience that must be maintained over multiple generations of human settlers unless AI advances to the point it can carry the load, and surely many other factors I've overlooked.

Lubricants might be made locally, but since they are available (in all probability) on Titan, outsourcing those might make more sense than making them locally.

(th)

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#156 2021-01-17 02:51:56

kbd512
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Re: Internal combustion engines for Mars

tahanson43206,

It will nearly always make more economic (total delivered cost of the product) and logistical (assurance of adequate supply) sense to make low-value products like lubricants locally.  Most of the synthetic motor oils are made from Methane base stocks, so part of your ACME "So, You Want to Build Technologically Advanced Human Civilization from Scratch Starter Chemistry Set" for Mars would include small-scale production of oils and greases.  There are also aerospace coating solutions such as Nickel Boron coatings that will provide some added protection against metal-on-metal wear.

Transporting anything at all between Titan and Mars will be obscenely expensive.  To begin with, any ship transiting that route must be nuclear powered, because there's simply not enough sunlight that far out into the solar system for photovoltaics to be practical, even if they achieve 100% conversion efficiency.  That said, all ships taking many thousands of tons civilization-level technology to another planet will be nuclear powered.  If not, then 99% of everything you're shipping is LOX/LCH4 or LOX/LH2, rather than mission-enabling cargo.  The entire purpose behind the logistics chain, or shipping business, is to deliver people and cargo at the lowest possible price point.  There's little point to an expensive Earth-to-Titan-to-Mars route grand tour of the solar system.  Titan is also cryogenically cold at all times, unlike Mars, so I sincerely doubt we'll see humans living there any time soon.

If we were intent on a practical piston-driven combustion engine solution for Mars, it would almost certainly use locally-made LNG, and we have plenty of examples of diesels using CNG or LNG here on Earth, to include all manner of heavy equipment, trucks, ships, and even a few aviation-related experiments that used LNG as a kerosene alternative.  A gas turbine with appropriate metering and combustor can geometry will happily combust any gas or liquid that vaporizes and burns in Oxygen (gasoline, kerosene, diesel, ammonia, methane, pure Hydrogen, finely milled coal-water slurry, etc).

New way to turn carbon dioxide into coal could ‘rewind the emissions clock’

Coal or pure Carbon is the only practical form of energy-dense fuel that can be stored indefinitely in a hard vacuum, irrespective of the temperature, without the use of a tank of any kind, since its a solid.  One of the intractable problems with any form of gaseous or liquid hydrocarbon is providing and maintaining the necessary tankage to store it.  A simple covered pit or unpressurized enclosure would be sufficient to store a solid fuel like pure Carbon or coal.

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#157 2021-01-17 08:21:46

tahanson43206
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Re: Internal combustion engines for Mars

For kbd512 re #156

Thank you for another interesting and helpful analysis.  I liked your "quote" but have not see it before, so I'm wondering if you made it up?

If you did, that's pretty remarkable, considering how many word smiths are plying their trade these days, let alone for the last 100 years, when the idea of trying to create an advanced technological civilization from scratch first began to glimmer.

You've probably noted that I came to this forum from Dr. Dartnell's Knowledge forum, which is based (in part) on his book about that very topic ...

He spent a lot of time trying to figure out how we (survivors) would rebuild civilization if it suddenly stopped.  A subphase of the study was the question of how to do what we (humans) are trying to do on Mars.  Your observations and recommendations in Post #156 fit nicely into that theme.

***
I'd like to see topics come into being around specific specializations.  Your recommendation of Carbon in solid form as a practical, reliable, storable energy storage mechanism is worth devotion of at least one individual to a lifetime of development, implementation and maintenance on Mars.

Todo: Add Carbon Solid Storage to MyHacienda list of specialties.

***
Regarding LNG ... this requires hydrogen ... I agree that there are many advantages to LNG (or similar liquefiable hydrocarbons, including gasoline) but the requirement for water to provide hydrogen is a complication the CO/O2-CO2 mixture does not (and will never) have.

Thus, for many years, any of the hydrocarbons will be niche products, unless an individual human being decides to build a business around one of them, and plans for and funds the operation before departing for Mars.

My Hacienda is set up to provide a framework for this forum to attract precisely that kind of individual.

Everything needed to achieve the capability you've forecast in your post can be (and in my opinion MUST be) proven on Earth, in a full-up Mars simulation.

One of the recent Mars Convention videos (I think 40 ... in that range) was about the ongoing (and to me impressive) Mars Simulation exercises sponsored by the Mars Society and carried out by (to me remarkable)  crews from around the world.  The My Hacienda vision is for a permanent working model of the entire settlement for Mars, built and in operation on Earth. That's why I am quite interested in the Mount Everest location.  It provides a habitat pressure by default.

The NASA example of building and testing probes on Earth is a model.  They have duplicates of Perseverance on Earth ready for testing if the Mars bound article encounters a problem.  I'd seeing a community on Earth fully implementing the technologies we've been discussing in this forum for nearly two decades, as a foundation for the actual venture on Mars, and as a working backup to assist with on site problem solving.

SearchTerm:Carbon Solid form kbd512 post http://newmars.com/forums/viewtopic.php … 16#p175916

(th)

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#158 2021-01-17 11:46:29

tahanson43206
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Posts: 7,680

Re: Internal combustion engines for Mars

As a follow up to the suggestion of kbd512 in a recent post, to consider solid carbon (coal equivalent) as an energy storage method for Mars.

There are so many potential advantages to this idea (for Mars certainly) that I decided to try to learn more about how it might fit into a mix of solutions there.

The article at the link below is potentially useful in trying to move the discussion forward, because it contains what appear to be reasonably accurate estimates of energy losses in various forms of carbon stored energy.

However, the article itself does not include discussion of coal (as I scanned it).

https://www.smartcitiesdive.com/ex/sust … as/185046/

If a currently registered reader of the forum has a suggestion of where to look for guidance about the potential efficiency of coal as an energy storage mechanism on Mars, I'd be interested.

Humans have certainly accumulated a decent amount of experience burning coal on Earth, so there may well be studies of the efficiency of various equipment designs to try to achieve the maximum possible performance from an energy recovery plant.

One tip I ran across was the practice of powdering coal before it is injected into a furnace for combustion.  There may be best practices available, showing the size of the particles that produce the most efficient combustion with the least waste of source material.

A power plant on Mars will have a distinct advantage over the same plant on Earth ... the oxidizer will be pure (or reasonably pure) Oxygen, saved from whatever process is used to make coal from atmospheric CO2.  Thus, there will be no losses due to interaction with Nitrogen molecules that are mixed in with the Oxygen on Earth.

Edit#1 ... since solid Carbon will be made to order on Mars, I am questioning whether compressing it to make bricks is the best possible practice? A stage of production which yields clumps of Carbon which are ideal for combustion would seem best for storage and delivery to a customer.  Perhaps such fine particles will clump together of their own volition as they are transported, so perhaps it won't make any difference to the customer.

(th)

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#159 2021-01-17 11:55:51

tahanson43206
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Registered: 2018-04-27
Posts: 7,680

Re: Internal combustion engines for Mars

In thinking further about a suggestion of kbd512 to consider solid Carbon (coal equivalent) as an energy storage method for Mars, I am reminded of the proposal (also by kbd512) to use a small, powerful, closed loop gas turbine as a way to convert thermal energy into rotary motion.

Solid Carbon would (presumably) deliver thermal energy to the intake barrel of a closed loop gas turbine as well as or potentially even better than CO.

Todo item: Discover and report the temperature that can be expected for combustion of finely ground particles of Carbon in a furnace fed by pure Oxygen.

Question related to above: Is the temperature that can be expected greater than can be handled by known materials?

(th)

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#160 2021-01-17 12:41:56

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Internal combustion engines for Mars

interest to hear kbd512 that a desiel can be converted to run via the same fuel source as a gasoline conversion can.

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#161 2021-01-17 16:56:38

kbd512
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Registered: 2015-01-02
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Re: Internal combustion engines for Mars

tahanson43206,

Yes, I just made that up.  It was done in jest, a tip-of-the-hat to the Wylie E. Coyote cartoons I watched as a child, but the problems associated with re-creating a technologically advanced civilization from scratch are still quite real.  Humans are still burning lots of coal here on Earth, though not so much here in the US, since we're switching over to natural gas.  We have an extreme abundance of natural gas from fracking, to the point that we've switched over some lubricants and plastics manufacturing plants to use Methane base stock.  Unfortunately, other nations don't have an abundant supply of natural gas.  For a gas turbine to burn coal-water slurry as fuel, it has to be very finely powdered (10 microns or less), but it has be done successfully.  If the particles are much larger than that, they tend to coke the combustor cans and any components downstream of the combustor cans, so special milling / crushing equipment is required.  Although diesels and boilers can use much larger particles without coking issues, the finer the particles, the less the coking of the engine's internal parts, no matter the type of engine used.

When I went back and re-read about Oxy-Fuel power plants, I also went back and looked at the flame temperature of CO in ordinary Earth-sea-level air, so I think I conflated the combustion temperatures of CO with some other fuel.  Apparently, problem I have with going off of memory is that I don't have any.

Typical Flame Temperatures in Air or Pure O2 (stoichiometric combustion):

Methane: 1,963C (air); 2,880C (O2)
Propane: 1,980C (air); 2,526C (O2)
Wood: 1,980C (air)
Hydrogen: 2,210C (air); 3,200C (O2)
Acetylene: 2,500C (air); 3,480C (O2)
Anthracite Coal: 2,180C (air); 3,500C (O2)
Carbon Monoxide: 2,121C (air); can't find a good source for flame temperatures in pure O2, but I expect flame temperature to be similar to coal, which means a diluent gas will be required (since even Thorium Dioxide would start sublimating below the flame temperatures produced)

No matter what type of fuel we use, a diluent gas will be required, because there are also temperature limits we must maintain to prevent rapid oxidation.  They use a mix of 95% O2 with 5% CO2 for burning natural gas (primarily CH4) in Oxy-Fuel power plants fuel here on Earth to keep the flame temperatures within tolerable limits.

As far as compressing Carbon into bricks is concerned, I would think we want a very fine Carbon powder so we can feed powder or slurry into the burner cans.

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#162 2021-01-17 17:36:41

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,625
Website

Re: Internal combustion engines for Mars

Kbd512 is quite right pointing out the flame temperature differences between air and pure oxygen. 

Another thing to consider is autoignition temperature,  which with air depends upon mixture ratio,  and time interval.  You have to be careful with references that report only one autoignition temperature.  This is usually for exposure times on the order of 1 full second.  That results in a lower temperature.  At shorter intervals,  the temperature is far higher.  The usual number is 1 msec.

CO has a 1-sec autoignition temperature with air of just about 1200 F.  At 1 msec,  this is closer to 1700 F.  I know this from many years of burning blends of CO,  carbon soot,  and inerts in gas generator-fed ramjets.  When compared to the 400-450 F for gasoline and 450F+ for diesel fuel,  you can readily see from either value that CO is a spark ignition fuel,  NOT a diesel fuel!  Gas turbine application does not care about this issue,  but it does care about flameholding,  generally unimportant in piston engines.   CH4 also has a really high autoignition temperature.   You want really low for diesel.

GW

Last edited by GW Johnson (2021-01-17 17:37:27)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#163 2021-01-17 18:26:57

tahanson43206
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Registered: 2018-04-27
Posts: 7,680

Re: Internal combustion engines for Mars

Thanks to kbd512 and GW Johnson for moving this topic forward!

As far as compressing Carbon into bricks is concerned, I would think we want a very fine Carbon powder so we can feed powder or slurry into the burner cans.

The above is from kbd512's post immediately above ...

I'm not sure how a creative engineer would apply this question, but here it is ...

On Mars, in the absence of water to make a slurry to carry carbon particles into a combustion chamber, we ** do ** have liquid CO ...

Is there (possibly?) an optimum combination of these two components to deliver a best-case performance for an Internal Combustion engine?

In this case, I'm thinking of ** both ** piston and turbine designs sitting in the lab, side by side, for evaluation.

The burner to deliver thermal energy to the closed loop gas turbine might perform better if it is fed by a mixture of coal particles (carbon fine grains) immersed in liquid CO, than it would with just liquid CO.

A piston engine might not perform as well, although I noted the reference to an engine running with a partial input of soot (which is finely divided Carbon).

The reference to soot was in GW Johnson #162, but the reference was to a ram jet, which does NOT operate using a complex set of rotating/moving machinery.

***
As a follow up to kbd512's suggestion to consider solid Carbon to store energy on Mars, I wondered what temperatures might be involved in sublimation of Carbon .... it turns out there are scientific studies of this phenomenon, relating to carbon arcs ...

https://www.sciencedirect.com/science/a … 2374900190

Abstract

Past efforts to measure the sublimation temperature of graphite by electric arc and cavity experiments are reviewed. Critical difficulties of interpretation of various anode reflectance measurements are pointed out, and resolved in terms of the emission of small graphite crystallites from graphite, and the existence of a shallow porous layer on the anode. It is argued that crystallites, which may form the major part of the mass loss, can partly obscure the surface from view. Also in the case of the “standard” carbon anode it is reasoned that the temperature of the observed surface can be controlled by thermal conduction to finely divided subliming carbon, which carries the positive charge of the quiet carbon arc close to the anode. It was concluded that the sublimation temperature of graphite at one atmosphere pressure lies between 3895 and 4020 K, and that little further experimental work needs to be done to define it more precisely, and to establish a new high temperature standard.

I'm not sure this is useful to know, since the intention of this topic (as I understand it) is to arrive at a rough consensus of the optimum design of equipment to deliver power to construction equipment and stationary plants on Mars, using available resources.

I have proposed splitting this topic into concentrations to help future Mars settlers to make head or tails of this constantly branching topic.

***
Thinking out loud ... I wonder if a carbon arc would help carbon granules to separate into individual molecules to better combine with Oxygen, and if the energy required to sustain the arc would be justified by improved performance of the combustor.

***
For GW Johnson ... following up on your post #162 regarding spark ignition ...

Manufacture of a spark plug on Mars using indigenous materials might prove challenging.  Can you think of a way that our intrepid settlers might approach that?

I did notice in one of the recent Mars Conference videos (the one about Curiosity) that there is a region on Mount Sharp where clay (iron clay to be specific) is found in some abundance.

Could this material feed into a ceramic suitable for a spark plug?

(th)

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#164 2021-01-17 19:27:36

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Internal combustion engines for Mars

The clay pottery are termed ceramics after firing in a kiln but what is a high temperature has lots more ingrediencies within it.
Remember the moxie unit to disassociate oxygen gets to 800c with at least 350 watts so getting even hotter require slot higher level of voltage not current to get the same effect as you are trying to break it down.

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#165 2021-01-17 20:05:13

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,680

Re: Internal combustion engines for Mars

For SpaceNut re #164

Following up on your observation about clay >> ceramics, I decided to ask Google about the manufacture of spark plugs ...

The snippets show below are (more or less) the tip of what appears to be an iceberg of information ...

How spark plug is made - material, making, history, used ...
www.madehow.com/Volume-1/Spark-Plug.html
Background
The Manufacturing Process
Quality Control
Each major element of the spark plug—the center electrode, the side electrode, the insulator, and the shell—is manufactured in a continuous in-line assembly process. Then, the side electrode is attached to the shell and the center electrode is fitted inside the insulator. Finally, the major parts are assembled into a single unit.
See more on madehow.com
Manufacturing Spark Plugs | How Are Spark Plugs Manufactured?
https://www.diycarserviceparts.co.uk/blog/2019/07/...
Manufacturing Spark Plugs: The Process
Step One. Spark plug shells are usually manufactured in one of three ways. One technique is for …
Step Two.
Step Three.
See full list on diycarserviceparts.co.uk

Based upon the observations by GW Johnson, I am persuaded that a piston engine designed for service on Mars is (most likely) going to be designed to use spark plugs. 

Manufacture of spark plugs would appear to be a specialization worth adding to the My Hacienda Registry.

(th)

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#166 2021-01-17 20:56:20

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Internal combustion engines for Mars

Most people know what a spark plug looks like but they are quite different looking for a desiel glow plug'
G013.jpg?bw=1000&w=1000&bh=1000&h=1000

Understanding Diesel Glow Plugs and How to Replace Them

The pencil element glow plugs are designed for a current of 12 volts and are operated in parallel. On some older diesels, the glow plugs operate on a current of 6 volts. A dropping resistor is used to reduce the voltage to 6 volts. After a glow period of 9 seconds, a "Quick-Start" pencil element temperature of approximately 1,652°F is attained, after 30 seconds the maximum temperature amounts to 1,976°F.

Quick-Start pencil element glow plugs are usually used in passenger vehicles while trucks use the slower pencil element glow plugs.

The pencil element is heated indirectly by means of a heater element. This heater element, a coil made of a resistance wire, is embedded and insulated in a ceramic compound. When the glow system is switched on, each glow plug is subject to a current of approximately 20 amps, peak impulse of approximately 40 amps. Under the influence of increasing heat, the inherent resistance of the glow plug increases and will limit the current to approximately 8 amps.

After a glow period of approximately 20 seconds a heater pencil element temperature of 1,652°F will be attained, after approximately 50 seconds the maximum temperature will be 1,976°F.

Sort of makes it ideal for cold weather mars conditions....

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#167 2021-01-18 07:14:20

tahanson43206
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Registered: 2018-04-27
Posts: 7,680

Re: Internal combustion engines for Mars

Following up on #166 .... the Russians have a lot of experience working in the far North.

I wonder if there are public documents about their experiences with machinery, and their "best practices" guidelines.

Canada and the Scandinavian countries come to mind as other Nations with extensive experience operating equipment in cold conditions.

I would imagine slow warming of equipment would be a part of everyone's "best practices".

Running some equipment all the time to prevent it from cooling is an expensive option.

Dealing with the cold is a subtopic this topic has not considered, to the best of my recollection.

(th)

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#168 2021-01-18 16:25:54

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,201

Re: Internal combustion engines for Mars

The way to use solid carbon as fuel would be to pre-burn it to produce CO which can then be burned in a spark ignition engine or gas turbine.  Probably you would want to cast the carbon into slugs that you load into the pre-burner by hand on an intermittent basis.  On Earth, wood gas vehicles have powered many country's transportation systems during severe fuel shortages.  This technology allowed WW2 Germany to maintain a limited car culture with no domestic gasoline supplies.  Most private vehicles were either fitted with wood gas burners or coal gas bags fitted on the roof.

The solution is somewhat cumbersome for a Mars vehicle, as you need to carry a burner with the vehicle.  It would need some means for lighting and manual input for loading. Compared to a CO/O2 powered vehicle, the oxygen tank would need to be twice as large.  But no CO tank is needed.  The carbon slugs could be compressed to twice the density of water and stored in a rack within the vehicle or on its roof.

It could be made to work.  But whether it is a superior option to storage of fuel as liquefied gas, in terms of weight, complexity and reliability, is questionable.

Last edited by Calliban (2021-01-18 16:28:46)


Interested in space science, engineering and technology.

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#169 2021-01-18 18:21:22

tahanson43206
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Registered: 2018-04-27
Posts: 7,680

Re: Internal combustion engines for Mars

For Calliban re #168

Thank you for this contribution to kbd512's suggestion ...

SearchTerm:Carbon Solid Practical for Mars http://newmars.com/forums/viewtopic.php … 86#p175986

I'd like to point out that burning the solid Carbon to make CO as an intermediate stage will itself yield thermal energy.

Without having more than an intuition about this, I would guess ??? that the amount of energy released in producing CO from the solid form of Carbon is exactly equal to the amount of energy delivered by the second phase, of combustion of the CO itself.

Here is an opportunity for those in the Registered Membership with a background in Chemistry to add to the flow of the topic.

As I understand the combination of the ideas of kbd512 and of Calliban, a vehicle would start out from the filling station with a load of Carbon blocks/sticks and a tank (or two) of Liquid Oxygen.  In order for this machine to be mobile, it would (presumably) have a residual supply of CO left over from the last outing.

A burner would consume Carbon to make CO, while generating energy that could be used for input to a closed cycle turbine as kbd512 has suggested, or to a Sterling piston engine, which (by that time) will be a well proven technology on Mars. 

As the vehicle makes its way to its destination, the CO would accumulate while the Carbon blocks/sticks are consumed.  At the job site, the CO would be available for consumption in whatever way is best suited to the circumstances.

In evaluating this scenario, a business planner would be thinking about the multiple factors of machine specification, fuel manufacture and storage, human participation in the process if required, maintenance issues to be dealt with, and lifetime of the entire system.

This is another interesting branch on the ever-proliferating trunk from SpaceNut's original Subaru engine.

(th)

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#170 2021-01-19 02:16:39

kbd512
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Registered: 2015-01-02
Posts: 4,748

Re: Internal combustion engines for Mars

tahanson43206,

Maybe you could mix in Carbon powder with CO, provided the CO was exceptionally pure and free of H2O or O2, but you'd probably also have to agitate the slurry to ensure it remains thoroughly mixed.  Alternatively, pure CO2 could be used to pressure feed Carbon powder into the combustor can.  The primary concern here is to prevent H2O or O2 from coming into contact with the Carbon powder.

Early on in my series of posts about the combustor can design, I mentioned the use of a high-energy spark plug in order to assure ignition.  Assuring ignition and complete combustion in the combustor can, rather than downstream where the hot CO2 exhaust will be captured for reuse, is relatively important.

Regarding selection of a gas turbine or diesel (these days both gas and diesels can be spark ignited while the engine is still cold and use compression ignition after the engine is hot enough for compression ignition), it really depends upon how you're going to use the engine (lots of variable output usage, or near full output most of the time) and how much CO2 working gas the diesel requires to produce equivalent power as its Earth-bound analog.

We'd need a very high dollar DuraMax and, of course, NREL's SCCO2 gas turbine with its high dollar PCHE and Copper radiator in order to test both of them.  Out of necessity, both engines would be constructed of the highest quality materials available, using fabrication methods that produce the most robust parts, within practical limits.  I think we'd need at least a couple million dollars to thoroughly test both prototypes with test equipment assistance provided by NREL and NASA, and probably another million to test the battery solution, with test equipment assistance provided by Panasonic and Tesla.  That's for prototype fabrication and testing only, not research and development of the competing solutions, which would require many millions of dollars.  All told, testing alone is probably a five million dollar project to adequately test and revise three workable portable generator / vehicle power pack solutions for heavy duty construction equipment.  Testing of the tracked construction vehicle is probably around twenty million dollars or so, with a development program near a quarter of a billion dollars or so.  If that seems like a lot of money, recall that this vehicle will serve as the basis for most construction equipment and mass transport of personnel on the surface of another planet, as well as ultimate durability on Mars.  Unfortunately, this is not the type of project someone can undertake in their home garage.

Before I forget again, here's a paper on Oxy-Fuel combustion for anyone who's interested:

Oxygen-Enhanced Combustion: Theory and Applications

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#171 2021-01-19 08:43:24

tahanson43206
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Registered: 2018-04-27
Posts: 7,680

Re: Internal combustion engines for Mars

For kbd512 re #170

Whew!  What a lot to try to unpack!  Impressive package in a one page post.

The key for an organization like the Mars Society is to (try to) provide an environment in which major global players find value in preparing for deployment of their brands on Mars.  The kinds of investments you've described are well within the discretionary budgets of a number of Nations, and many large corporations. Large Universities (and perhaps even smaller ones) can participate through the tried and true securing of grants to perform work deemed necessary by funders.

SearchTerm:Oxygen Enhanced Combustion ... link to paper: http://newmars.com/forums/viewtopic.php … 07#p176007

Discussion of possible slurry of carbon fine solid particles with liquid CO to deliver carbon to combustor

SearchTerm:slurry I'm hoping the concept of a slurry in this context will be easier for future searchers to find this post

It should be possible to model the slurry under discussion here in modern advanced software. 

My expectation is that the performance of the fuel will be directly related to the proportion of CO and carbon particles.

On the other hand, the efficiency of delivery of carbon particles to the combustion chamber by the CO carrier is (a guess here) variable and not necessarily linear.  The idea (as I understand it) is to achieve maximum possible (optimum) performance of a power delivery technology, using carbon separated completely from Oxygen from the atmosphere of Mars, carried in a liquid CO transport mechanism that itself contributes to the effectiveness of the fuel.

The supply of O2 needed to match the stored energy of the fuel will be greater than it would be for CO alone.

The machine designer could experiment with mixtures to try to find the optimum distribution of factors for a given application

A large bulldozer or similar regolith moving machine might benefit by employing a higher density of carbon powder in the mixture, because the volume of tankage needed for fuel and oxidizer would be manageable in proportion to the overall mass of the machine.

A small, light personnel transporter might do better with a straight CO flow.

For members of ** this ** organization, the key (it seems to me at least) is to develop ideas as far as possible, and find large players in the right combination, willing and able to invest in order to insure their brands are present in the communities on Mars.

If readers of this post have not already watched them, I'd like remind everyone that the recent Mars Conference videos include a set of three which report on the visions for City-State entities on Mars.  The students and their professors invested a lot of time and thought in working out scenarios which might lead to populations on the order of 1,000,000 people.

I detected NO thought of how to enlist brands to make the needed investments to insure their names are part of the future we can expect to unfold on Mars.

The members if ** this ** tiny subset of the Mars Society are in position to think of and communicate with potential players on the scale kbd512 has forecast.

Edit: Another variable in performance of the slurry system is the density of the mixture, as determined by pressure of the CO carrier tanks.

My guess is that volume of the tankage is going to be more important to the vehicle designer than would be the mass of the fuel and oxidizer.

There is (presumably) some combination of mass, pressure, energy storage capacity and efficiency of combustion that will be achieved by the vehicle designer for the application needed.  Related factors, as I have tried to point out repeatedly, is the importance of maintainability in the field and at the home base, not to mention the ease or difficulty of manufacture of components in the first place.

Whatever designs flow from these discussions, I call for planning ahead to  insure systems can be maintained in perpetuity by subsequent generations on Mars itself.  Designs that call for ultra-precise turbine fan blades, for example, are fine if they can be manufactured to the required specifications by equipment on Mars, operated by people who understand the chemistry, physics and best practices needed to build and operate and maintain that machinery.

(th)

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#172 2021-01-19 12:09:44

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,680

Re: Internal combustion engines for Mars

For kbd512 (and any chemists in the membership who would be willing to help out) ...

I asked Google for help with the question of the optimum mix of solid carbon (eg, soot) particles and liquid CO.  Nothing specific to that request came back, but the article shown below may be helpful:

https://energyeducation.ca/encyclopedia/Soot

References
↑ Wikimedia Commons. (September 8, 2015). Soot Roet [Online]. Available: https://upload.wikimedia.org/wikipedia/ … ,_roet.jpg

Jump up to:
2.0 2.1 2.2 WiseGeek. (September 8, 2015). What is Soot? [Online]. Available: http://www.wisegeek.org/what-is-soot.htm

Jump up to:
3.0 3.1 3.2 3.3 Center for American Progress. (September 12, 2015). Soot Pollution 101 [Online]. Available: https://www.americanprogress.org/issues … ution-101/
↑ U.S. Environmental Protection Agency. (accessed September 26, 2015). Black Carbon [Online], Available: http://www3.epa.gov/airquality/blackcarbon/basic.html
↑ U.S. Environmental Protection Agency. (Accessed September 26, 2015). Effects of Black Carbon [Online], Available: http://www3.epa.gov/airquality/blackcarbon/effects.html
↑ American Chemical Society. "Methane and oxygen react". Internet: http://www.middleschoolchemistry.com/mu … r6/lesson1, [October 25,2013]
Authors and Editors
Jordan Hanania, Ashley Sheardown, Kailyn Stenhouse, Jason Donev
Last updated: January 4, 2019
Get Citation

As a reminder/explanation for readers who chance upon this topic for the first time, the object of the immediate exercise is to find a set of practices that are optimized to produce useful power in machinery on Mars, where Carbon Dioxide is abundant but water is scarce.

The immediate focus is the idea (of kbd512) to consider mixing Carbon particles (eg, soot) with liquid Carbon Monoxide, to make a versatile fuel which is easy to prepare, store and to use (with liquid oxygen) in a vehicle from the largest bulldozer to the smallest personal transport vehicle.

(th)

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#173 2021-01-19 18:16:36

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Internal combustion engines for Mars

Here is another combination co + o3 + co2 to moderate....exhaust is all co2....

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#174 2021-01-19 20:58:28

kbd512
Administrator
Registered: 2015-01-02
Posts: 4,748

Re: Internal combustion engines for Mars

tahanson43206,

For diesel development, I suspect someone like Gale Banks would need be involved, since he does quite a bit of engine development for the US military and has the test equipment required.  However, engine manufacturers like GM or Cummins or Detroit Diesel also do quite a bit of engine development.  TARDEC (Tank and Automotive Research and DEvelopment Command) works with various OEMs on clean-sheet engine development, such as the OPOC (Opposed Piston, Opposed Cylinder) engine being developed for new military ground vehicles.  NREL worked with GE on the design of the SCCO2 gas turbine and UK-based Heatric was tapped to produce the diffusion bonded PCHEs.  They did have to create special tools to produce the 125kW turbines.  No new materials development was required, though.  NASA works with defense industry OEMs like Yardley and Eagle-Pitcher to produce space-rated Lithium-ion batteries.  Again, we're talking about very involved development that requires OEM-level fabrication and T&E resources.  A vehicle chassis would be developed by corporations like BAE Land Systems or General Dynamics Land Systems, and hiring them is not cheap.  I would involve DARPA with the vehicle development program because they have a well established track record of developing fundamentally new technologies that cross engineering domains.  As I said before, none of this is cheap or easy to do.  Anyone who believes otherwise is not dealing with reality.  It's not an amateur level task.  Bubba is not going to produce a fully functional and properly tested moon rover in his garage, no matter how much he knows about tanks and engines from his time in the Army.  Bubba will test something until he gets it to work.  Gale will test something until he's found every last way to destroy it, and if that means destroying a hundred different engines in dozens of slightly different ways, his company has the testing resources and the government's financial backing to do it.  This is why everyone from the military to weekend street racers lean on people like Gale to come up with durable and reliable solutions- they don't have the resources (human, equipment, or capital) to do it themselves, and most of them don't have the requisite technical knowledge, either.

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#175 2021-01-19 21:31:32

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,680

Re: Internal combustion engines for Mars

For SpaceNut re #173

Thanks for an interesting suggestion .... you did not specify liquid Ozone in your post.  I had to ask Google about Ozone, and specified liquid because we had previously been discussing liquid Oxygen (O2) for the hypothetical Internal Combustion engine on Mars.

I was surprised to find this caution about liquid Ozone:

At 161 K (−112 °C; −170 °F), it condenses to form a dark blue liquid. It is dangerous to allow this liquid to warm to its boiling point, because both concentrated gaseous ozone and liquid ozone can detonate. At temperatures below 80 K (−193.2 °C; −315.7 °F), it forms a violet-black solid.
Chemical formula: O₃
Melting point: −192.2 °C; −313.9 °F; 81.0 K
Molar mass: 47.997 g·mol−1
Solubility in water: 1.05 g L−1 (at 0 °C)
Ozone - Wikipedia
en.wikipedia.org/wiki/Ozone
en.wikipedia.org/wiki/Ozone

For kbd512 re #174

Thank you for details about how development on the scale of the proposed (hypothetical) machinery for Mars might happen.

I lean toward optimism, so can imagine that the prospect of landing a contract for a machinery configuration for Mars might be of interest to qualified people and organizations.

(th)

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