ESE's works engine tuner

[Moooools]

Two significant difference between water and a designer-wax: #1: You're not allowed water.

#2: Cooling water isn't changing phase from solid/liquid/gas. The various thermal waxes are designed to phase change at a specific temp. Applying heat initially simply warms the wax up, but as the temperature approaches that required to change the wax from solid to liquid the temperature simply stops rising. And it'll remain constant as the wax soaks up the huge quantities of energy required to change phase.

So a wax designed to change at 50deg and absorb 13422kJ will only need a small portion of that 107 litres.

But I'm not a process engineer, which is why there's some numbers missing from the above.

Oooops. Thought you were talking about water. I completely failed at reading the previous thread entries. It was late and was in that 'hey I could work that out mode'.

My revised estimate is 44kg of wax.

I got to this by adding the energy of heating the wax from 20deg to 50deg to the energy expended in melting the wax. Which is 305kJ/kg.

13422/305 = 44kg.

You would also run into problems with ensuring you don't end up with all of the wax around the cylinder boiling and the rest being at ambient temperature. With a liquid it is easy to pump around but a solid will experience a temperature gradient.

The reason it isn't 507 times better than water is that the energy required to melt it only happens over a couple of degrees. It is kind of a one time event and is hard to compare to heating water.

Water has a Cp of 4.18 but you get to heat it through 30deg. 30*4.18 which is 125.4kJ/kg. SO the wax is only about 2.5 times as good for the same temperature range at 305kJ/kg.

[Moooools]

that third third third rule Mooools used. The assumption that all the exhaust heat loss needs to included puzzles me?
.

It isn't included. The rule goes that if you measure an output of 30hp at the crank, there is also 30hp going to the exhaust stream, and also 30hp going to the cooling. The engine is putting out 90hp and you can get 30 of that to the rear wheel pretty much.

[husaberg]

It isn't included. The rule goes that if you measure an output of 30hp at the crank, there is also 30hp going to the exhaust stream, and also 30hp going to the cooling. The engine is putting out 90hp and you can get 30 of that to the rear wheel pretty much.

Cheers that makes more sense.

Oooops. Thought you were talking about water. I completely failed at reading the previous thread entries. It was late and was in that 'hey I could work that out mode'.

My revised estimate is 44kg of wax.

I got to this by adding the energy of heating the wax from 20deg to 50deg to the energy expended in melting the wax. Which is 305kJ/kg.

13422/305 = 44kg.

You would also run into problems with ensuring you don't end up with all of the wax around the cylinder boiling and the rest being at ambient temperature. With a liquid it is easy to pump around but a solid will experience a temperature gradient.

The reason it isn't 507 times better than water is that the energy required to melt it only happens over a couple of degrees. It is kind of a one time event and is hard to compare to heating water.

Water has a Cp of 4.18 but you get to heat it through 30deg. 30*4.18 which is 125.4kJ/kg. SO the wax is only about 2.5 times as good for the same temperature range at 305kJ/kg.

Read the link in my post read all the way to the endhttp://www.autospeed.com/cms/article...ooler&A=110772

•Melting point: 52 degrees C
•Specific heat: 3.27 kJ per kg per degree C
•Specific heat of fusion: 210 kJ/kg

So to increase the temp of 1kg of the wax from 47 to 52 degrees takes 16.35kJ, but to push it past 52 degrees takes nearly 13 times as much energy. (Or, to risk causing confusion, you could dissipate in it a power of 14kW for 15 seconds to melt 1kg.)

Then consider there is a substance that is actually 570 times more efficient than simple paraffin wax.http://www.sciencedirect.com/science...27024810000474
This was on the first page of a google a few seconds at most.
The required energy to phase change is huge.




As Wob inferred it is just a diversion bandaid I found in a few seconds on google When the real answer is water cooling.
But as Rob found when he did the 24mm venturi There are ways around technical rules.

[Frits Overmars]

there are competition classes that basically specify a standard production vehicle and a very short list of permissible alterations. The objective is obviously to remove any variables other than the pilot.

I agree. In Dutch moped racing there are two classes with a lot of technical freedom. Together they share one page in the rulebook with room to spare. That part of the rulebook is 'allowed unless mentioned'.
There are also two classes where the bike has to remain 99% standard. Together they occupy 8 pages in the rulebook. They also cause eight times the amount of discussion at scrutineering. This part of the rulebook is 'forbidden unless mentioned'. And let me tell you: I hate to write this kind of rules.
These standard classes came into being because of the increasing number of riders that don't know a spark plug from an exhaust pipe. They offer great racing but zero technical inspiration; they have produced riders of european championship level, but decent mechanics are threathened to become extinct.

.. I feel the discussion is both interesting and relevant. Of course my time would be better spent focusing on handling, but that's not nearly as interesting.

Oh, but it is. Once you experience what you can achieve by turning a pair of shock absorber knobs, you'll be hooked.

Old technology is what we have to work with and the first step to making more power with the ports in the right place on these outdated engines is to organise sufficient effective cooling for the target power output. If you want to explore the limits of what is possible with the old engines then, its figuring out the cooling first, then making power. Otherwise you really will keep seizing all the time.

True, and it's not only valid for old engines. Modern engines are not so prone to seizing, but they won't produce real power either without good cooling.

Nowadays an engine needs a large crankcase volume, all the port area you can cram into the cylinder circumference, good ducts for efficient flow and directional control, an exhaust that sucks and blows hard at the appropriate moments, and cooling, cooling, cooling.

[Yow Ling]

Cheers that makes more sense.


Read the link in my post read all the way to the endhttp://www.autospeed.com/cms/article...ooler&A=110772


Then consider there is a substance that is actually 570 times more efficient than simple paraffin wax.http://www.sciencedirect.com/science...27024810000474
This was on the first page of a google a few seconds at most.
The required energy to phase change is huge.




As Wob inferred it is just a diversion bandaid I found in a few seconds on google When the real answer is water cooling.
But as Rob found when he did the 24mm venturi There are ways around technical rules.

You seem to have substituted "570 times higher thermal diffusivity" with "570 times more efficient than" I cant see the similarity myself

[husaberg]

You seem to have substituted "570 times higher thermal diffusivity" with "570 times more efficient than" I cant see the similarity myself

570 times more Efficent at thermal diffusivity than paraffin wax
Thermal diffusivity is a measure of thermal inertia.
My guess is this is the stuff added...... Pyrolytic carbon.
https://www.momentive.com/Products/Main.aspx?id=22860
It seems from a quick peak that when arranged and treated properly to conduct most of its heat in one direction only.

Which made me think of a diode. Form 3 again. What's that year 8 schooling now.


I wonder if there was such a thing as a heat Diode. Well it turns out there actually is.
http://en.wikipedia.org/wiki/Thermal_diode
http://newsoffice.mit.edu/2009/thermoelectric
http://www.popsci.com/technology/art...ay-heat-diodes
But like I said I am only spit balling

[Yow Ling]

here is a thermal diode

[husaberg]

here is a thermal diode

Yeah I seen that and I have seen the Propane thermal engine
But the diodes turns waste heat directly into electricity at 18% efficiency at the moment. (Three birds one stone.)
Which I guess is about half the efficiency of a old coal fired power station.

[peewee]

what you guys think. picked up some new used carbs to try. ill need to make a proper intake manifold but it shouldnt be to difficult considering they will be a nearly straight on shot. any advice for converting these to methanol ? oh ya and should the manifold be as short as possible ?

[Moooools]

Cheers that makes more sense.
Then consider there is a substance that is actually 570 times more efficient than simple paraffin wax.http://www.sciencedirect.com/science...27024810000474
.

You seem to have substituted "570 times higher thermal diffusivity" with "570 times more efficient than" I cant see the similarity myself

Yow has it right. A higher thermal diffusivity in this case will just cause a lower temperature gradient through the wax (570 times lower though!). You will still need 44kg of the stuff.

[husaberg]

Yow has it right. A higher thermal diffusivity in this case will just cause a lower temperature gradient through the wax (570 times lower though!). You will still need 44kg of the stuff.

Nah the original post your KG's don't add up.
Read why they use Paraffin wax.
Your calculations miss the phase change.
I am not interested in its ability to shed the heat afterwards, only is ability to draw it away. Ie one plane heat conductivity

[Moooools]

Nah the original post your KG's don't add up.
Read why they use Paraffin wax.
Your calculations miss the phase change.
I am not interested in its ability to shed the heat afterwards, only is ability to draw it away. Ie one plane heat conductivity

No I accounted for the phase change.

98kJ/kg comes from heating the solid wax from 20deg to 50deg.
210kJ/kg comes from the phase change.

Still only ~305kJ/kg.
13422/305 = 44kg.

It doesn't matter if the wax gets 570 times better at conducting heat; it can still only absorb 305kJ/kg for this temperature change.

[husaberg]

No I accounted for the phase change.

98kJ/kg comes from heating the solid wax from 20deg to 50deg.
210kJ/kg comes from the phase change.

Still only ~305kJ/kg.
13422/305 = 44kg.

It doesn't matter if the wax gets 570 times better at conducting heat; it can still only absorb 305kJ/kg for this temperature change.

but to push it past 52 degrees takes nearly 13 times as much energy.
How many bikes do you know that run under 52 degrees?
Also races are not indefinite periods of time.
Nor is power output. Percentage of time at full throttle rarely exceeds 2 percent.
Also its not only wax though is it if you use a composite.

[Haufen]

What kind of coolant is allowed in MotoGP racing? Is it pure water only, or are you allowed to mix with some anti-corrosives, too?

[senso]

Give the bluish tint that the RSA cylinders have in some photos I would risk to say that they run some coolant liquid that is more than just plain water.