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Are these oranges there in the background?
Thanks, ClinicalCosmologist ( talk) 10:35, 13 December 2017 (UTC)
I have the feeling that should exist somewhere in a textbook, so I am asking if someone has seen it before.
Assume a closed chamber at volume V containing a flammable homogeneous mixture of gases, which we ignite (e.g. by spark ignition). As the flame front propagates, the fraction of burnt gases increases, heat is generated by the combustion and temperature/pressure rises. Under reasonable combustion conditions, the pressure is at equilibrium between fresh and burnt gases, but the temperature is not (burnt gases are much hotter).
Experimentally speaking, accessing to instantaneous pressure inside the chamber is easy, but transient temperature is trickier to measure. I would think that under reasonable hypotheses (described below) the pressure signal is enough to solve a simple two-phase-at-pressure-equilibrium model and recover the full history, but I have not found a ref that does so yet. The trick is that during combustion, temperature increases, hence burnt gases expand and compress the fresh gases (which heats them) until the pressure is at equilibrium between the two phases. Hypotheses:
You have of course access to all relevant constants ( heat capacity, molar mass of the gases, lower calorific value for the fuel, etc.). I tried doing it by hand, but after an hour of paper-inking I had no success. Bonus point if the answer allows for a variable (but given) total volume V, but I think I can fiddle with a constant-V solution easily enough. Tigraan Click here to contact me 10:48, 13 December 2017 (UTC)
I remember seeing a series of 5-10 videos that helped explain relativistic speeds of a train that showed how 2 observers would witness seemingly paradoxical behavior of the train (such as passing through a tunnel that was shorter than the train's length) but that to one observer, the train would appear longer than the tunnel. It then took this paradox to further extremes such as having 2 gates that would "close" for a millisecond while the train was inside the tunnel, but to one observer (but not the other) the gates would close at different times, even if they closed simultaneously due to relativistic effects. 67.233.34.199 ( talk) 17:22, 13 December 2017 (UTC)
knowingly and intentionally [direct] others to a site that violates copyright. If you think that's an overbroad interpretation of statute/jurisprudence, call the WMF; if you think that's the US law that is stupid, call your congressman. Tigraan Click here to contact me 13:35, 15 December 2017 (UTC)
The "time dilation" + "train" keywords helped me find the video thanks! 67.233.34.199 ( talk) 08:04, 14 December 2017 (UTC)
also no copyright intended (no copyright issue imo) but can someone tell me what "hatted" means? I read the term on Steve_Baker's talk page (an old friend) he got me introduced to bitcoin because he worked at a bitcoin company 18 months ago. 67.233.34.199 ( talk) 08:05, 14 December 2017 (UTC)
Science desk | ||
---|---|---|
< December 12 | << Nov | December | Jan >> | December 14 > |
Welcome to the Wikipedia Science Reference Desk Archives |
---|
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages. |
Are these oranges there in the background?
Thanks, ClinicalCosmologist ( talk) 10:35, 13 December 2017 (UTC)
I have the feeling that should exist somewhere in a textbook, so I am asking if someone has seen it before.
Assume a closed chamber at volume V containing a flammable homogeneous mixture of gases, which we ignite (e.g. by spark ignition). As the flame front propagates, the fraction of burnt gases increases, heat is generated by the combustion and temperature/pressure rises. Under reasonable combustion conditions, the pressure is at equilibrium between fresh and burnt gases, but the temperature is not (burnt gases are much hotter).
Experimentally speaking, accessing to instantaneous pressure inside the chamber is easy, but transient temperature is trickier to measure. I would think that under reasonable hypotheses (described below) the pressure signal is enough to solve a simple two-phase-at-pressure-equilibrium model and recover the full history, but I have not found a ref that does so yet. The trick is that during combustion, temperature increases, hence burnt gases expand and compress the fresh gases (which heats them) until the pressure is at equilibrium between the two phases. Hypotheses:
You have of course access to all relevant constants ( heat capacity, molar mass of the gases, lower calorific value for the fuel, etc.). I tried doing it by hand, but after an hour of paper-inking I had no success. Bonus point if the answer allows for a variable (but given) total volume V, but I think I can fiddle with a constant-V solution easily enough. Tigraan Click here to contact me 10:48, 13 December 2017 (UTC)
I remember seeing a series of 5-10 videos that helped explain relativistic speeds of a train that showed how 2 observers would witness seemingly paradoxical behavior of the train (such as passing through a tunnel that was shorter than the train's length) but that to one observer, the train would appear longer than the tunnel. It then took this paradox to further extremes such as having 2 gates that would "close" for a millisecond while the train was inside the tunnel, but to one observer (but not the other) the gates would close at different times, even if they closed simultaneously due to relativistic effects. 67.233.34.199 ( talk) 17:22, 13 December 2017 (UTC)
knowingly and intentionally [direct] others to a site that violates copyright. If you think that's an overbroad interpretation of statute/jurisprudence, call the WMF; if you think that's the US law that is stupid, call your congressman. Tigraan Click here to contact me 13:35, 15 December 2017 (UTC)
The "time dilation" + "train" keywords helped me find the video thanks! 67.233.34.199 ( talk) 08:04, 14 December 2017 (UTC)
also no copyright intended (no copyright issue imo) but can someone tell me what "hatted" means? I read the term on Steve_Baker's talk page (an old friend) he got me introduced to bitcoin because he worked at a bitcoin company 18 months ago. 67.233.34.199 ( talk) 08:05, 14 December 2017 (UTC)