Stirlingengineforum.com

heat is not hot, or internal energy. Temperature is just one variable in internal energy. Work = P•∆V Thermal internal energy U: U=M•Cv•T Heat requires two masses at two different temperatures and a thermal conduction connection. I was taught wrong in school. It took a lot to break that bad thought...

The pressure and temperature won't drop if the right amount of heat/energy is being put into the gas as it expands. ... What determines the "right amount"? Aside from the opinion of "Stroller". "Opinion" :laugh: We can calculate the Work W (in the form of heat energy) ...

Or is 3.65j the energy needed to expand 100cc at 300k to 200cc at 600k? Yes. This is what Charles law tells us: "When the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be in direct proportion." Hence: V1/T1 = V2/T2 The equation shows that, ...

Charles law states V1/T1 = V2/T2 So if we have a 1cm^2 tube with 100cc of air under the piston, then we need to double its volume to lift our piston by 1m. If we start with 300K air then 100/300 = 200/T2 = 600K 3.65 Joules are needed to raise 100cc of air from 300K to 600K We used 1J raising the 10...

Alternatively, we can calculate the Work W that has to go into the gas to keep it at a constant temperature T as it expands from V1 to V2

W = RTln(V2/V1)

Gas constant R is 0.082 L atm K−1 mol−1

Charles law states V1/T1 = V2/T2 So if we have a 1cm^2 tube with 100cc of air under the piston, then we need to double its volume to lift our piston by 1m. If we start with 300K air then 100/300 = 200/T2 = 600K 3.65 Joules are needed to raise 100cc of air from 300K to 600K We used 1J raising the 102...

Stroller - I think Vincent is suggesting a bang-on demo akin a sloooow isothermal expansion lifting a rock. In this manner, the only 'fuzzy belief' required is that an isothermal expansion has no change in internal energy, whereby all heat input 'must be' converted into work, no ands, ifs, or buts....

I don't follow baseball but I guess you're from across the pond then? For starters, I'd like to see a test conducted that proves actual destruction of heat. Not a reduction of, say, internal energy per cubic centimeter, but actual destruction/ conversion of heat energy. Take a bicycle pump, extend ...

Spacefog_ wrote: ↑Wed May 15, 2024 4:09 pm Does this look legit to you guys? https://www.youtube.com/watch?v=ziZYVbLnSdM

Yeah. 1.4Watt (varying) at full chat looks about right for an enlarged Ky-Ko fan engine design.
It's not going to blow your hat off, but it would trickle charge a motorcycle battery or charge a smartphone.

For anyone interested in the history of this maximum power-efficiency relationship, it goes back to a book by Henri B. Reitlinger in 1929: Even if not so ancient, the history of the heat engine efficiency at maximum power expression has been yet turbulent. More than a decade after the publication of...

Adrian Bejan: Entropy generation minimization: The new thermodynamics of finite‐size devices and finite‐time processes. Entropy generation minimization (finite time thermodynamics, or thermodynamic optimization) is the method that combines into simple models the most basic concepts of heat transfer,...

I enjoyed the additional historical context around Carnot in the linked video. It tells us that following the invasion of France by the Germans, Ruskies and Prussians he puzzled out his ideal powerless reversible engine in an attempt to give his native France the upper hand in steam engine developme...

Temperature is a measure of the average kinetic energy of the particles in a sample of matter, expressed in terms of units or degrees designated on a standard scale. So, kinetic energy transferred to the thermometer bulb. But Joules are also representative of energy transfer. So this is all about en...

This more advanced analysis of heat engines takes into account the temperatures of the working fluid, because it accounts for the heat flux across the engine walls by considering 4 temperatures, rather than the two used by Carnot. https://tallsnaps.files.wordpress.com/2024/05/chambadal-novikov-buche...

Chambadal and Novikov published their work on this in the late 1950s. Not so much 'cherry picked' as 'up-to-date state of the art', back then. But they published in the Russian literature, which is likely why it didn't filter through to western physics until 1994. Better late than never. None powere...