Questions tagged [combustion]

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Hydrogen discharge tube emission spectrum different from emission during burning

In "How is it possible some substances burn with an invisible flame" it is stated that light emitted from burning hydrogen is almost invisible, more precisely: You say that hydrogen flames are ...
mijen67's user avatar
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Surface fluctuations in the combustion of ethanol in a woosh bottle

A whoosh bottle demonstration typically involves igniting ethanol vapor in a large bottle with a narrow opening. The rapidly expanding gas creates the whooshing noise as it vacates the container. This ...
zahbaz's user avatar
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What happens to the composition of a mixed gas plasma when de-ionizes back into a gas

I've been thinking about this question for the past few days, but I'm not very well versed in plasma physics. I am an aerospace engineering student in my senior year of college. A little while ago, I ...
Mattias's user avatar
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Why does hot oil inflame when windows are opened?

A Japanese Youtuber posted a video on her survival from burns on one side of her face. She said left oil heating on the stove and noticed it producing lots of black smoke- hit the smoke temperature ...
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How much UV does a hydrogen flame emit?

A hydrogen flame is invisible but emits ultraviolet (and infrared) radiation. How much UV does a hydrogen flame emit for a given reactant flow or a given heating power? Could a hydrogen flame be used ...
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What's the minimum time scale for a candle to be lit in order for it to establish a steady state?

My Understanding When a candle is lit initially, it goes through a few stages (see, e.g. this explanation from the National Candle Association): Wick burns. Crusted wax on wick melts, evaporates ...
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Fires with chlorine

could a fire with it's fuel consisting of mostly carbon like coal or wood use chlorine instead of oxygen. My thinking goes that when fire burns it sucks in oxygen and that bonds with carbon to make ...
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Flame under immense pressure and moderate temperature

Consider the flame inside a rocket engine's pre-burner, where the pressure is truly immense (400~600 bar) but the temperature is quite mild (<1500 K), and the flame is of the premixed type. Under ...
Meatball Princess's user avatar
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How does adding high energy density metallic nanoparticles increases the burning rate during a combustion process?

I have been reading about combustion and oxidation, and I have found out that by adding metallic nanoparticles (e.g aluminium nanoparticles) the burning rate of the propellant increases while the ...
dareToDiffer07's user avatar
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Breaking the Strain Rate into normal and tangential components

I was looking through a set of notes on combustion and I found this definition of the strain rate at a point on a flame surface: $K_s = -\mathbf n \cdot \mathbf E \cdot \mathbf n $ where $ \mathbf n$...
EPH's user avatar
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Is flame temperature and the temperature above the flame about the same?

This is a practical question that looks not that academic. I'm trying to design an integrated forge that can do heating and forging together. Blacksmiths usually make a forge kiln like Figure 2, as ...
iry's user avatar
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Why can't you blow out a smouldering reaction?

It's possible to blow out a candle flame so how come once it's blown out, if the wick is still smouldering, blowing on it just makes it glow brighter instead of stopping the smouldering reaction.
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Difference of density ratio in 1D detonation(C-J point) and 1D normal shockwave as p2/p1 goes infinite

1D detonation equations: $$ \rho_1u_1 = \rho_2u_2 $$ $$ p_1 + \rho_1u_1^2 = p_2+\rho_2u_2^2 $$ $$ c_pT_1 + \frac{1}{2}u_1^2 + Q = c_pT_2 + \frac{1}{2}u_2^2 $$ 1D normal shockwave equations: $$ \...
ArtificiallyIntelligent's user avatar
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What wavelengths of electromagnetic radiation are emitted by the LH2/LOX reaction?

Rocket engines such as the Rocketdyne Rocket System 68 and the Space Shuttle Main Engine use liquid hydrogen and liquid oxygen as propellants. The exhaust from this type of engine is notable in ...
RocketLauncher's user avatar
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Would a candle in very high gravity blow itself out?

A candle creates an upward draft of hot air, without which the flame would be spherical. The buoyancy generated is proportional to the density difference as well as the strength of gravity. Suppose a ...
Kevin Kostlan's user avatar
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Why does force decrease with increase in velocity in case power was constant?

Suppose an internal combustion engine burns the same amount of fuel every cycle (regardless of engine or car speed ) that means it creates the same pressure every cycle and the force on the piston due ...
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If the human eye can see green so well, why don't flames and such that emit a broad rangecof wavelengths ever appear green?

Similar questions have been posted many, many times before, but.... If a black body at the correct (average) temperature is 'centered' on the green, and human eyes our retinal cones) see best in the ...
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Why does a gunpowder makes sound when it burns but not like a candle?

My class teacher asked this question, when a fire-cracker ( which has gunpowder in it) burns, it explodes and make a sound while when a candle is burnt it doesn't, and I also want to know why does ...
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Why is the the temperature change due to the combustion of paraffin wax so high (10000 Kelvin)?

I'm trying to work out the temperature change (I got something like 10k Kelvin,hotter than the Sun's core...) caused by the combustion of paraffin wax which has a molar enthalpy of combustion $E^{wax}...
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Do gas-powered plants use Higher Heating Value(s) (HHV) or Lower Heating Value(s) (LHV)?

Does anyone know if natural gas power plants, and other utilities for that matter, obtain as much energy as (reasonably) possible from burning methane (or coal, or whatever)? Where would one find that ...
Kurt Hikes's user avatar
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Fighting wild fires with sub zero air

I understand this is probably too costly to be practical, but was intrigued how one might use the mechanism of fire combustion against itself. Fires produce their own retardants (water and carbon ...
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Equivalence between LHV and energy balance in combustion

I have seen in many textbooks the following equation for a combustion chamber $$ \eta \, m_{fuel} LHV = m_{out}h_{out}(T_{out}) - m_{in}h_{in}(T_{in}). \quad (1) $$ Consider now the stoichiometric ...
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Would it be correct to state that all the forms of everyday matter (mountains, tables, buildings, people, etc.) are in a metastable state?

We had a fire going in the backyard of a friends house this weekend, and after thinking about the chemical reactions occurring in the wood (and anything else we threw into the pit), I started to ...
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Where do combustibles(gas etc.) fit into the first law?

The first law can be written as $dU=dW + dQ$. As I understand it $W$, work, is mechanical energy from winding up springs, things spinning, flying etc. It's kinetic and potential. As I understand it $Q$...
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Oil Lamp Dynamics

Here is a photo of an oil lamp I am making. I am facing a few problems.first how its made. Its a glass bulb with a custom fit plug made out of aluminium.The bulb balances by way of a neodymium ...
Rupin's user avatar
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