What is Fuel: Definition and 579 Discussions

A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but has since also been applied to other sources of heat energy such as nuclear energy (via nuclear fission and nuclear fusion).
The heat energy released by reactions of fuels is converted into mechanical energy via a heat engine. Other times the heat itself is valued for warmth, cooking, or industrial processes, as well as the illumination that comes with combustion. Fuels are also used in the cells of organisms in a process known as cellular respiration, where organic molecules are oxidized to release usable energy. Hydrocarbons and related oxygen-containing molecules are by far the most common source of fuel used by humans, but other substances, including radioactive metals, are also utilized.
Fuels are contrasted with other substances or devices storing potential energy, such as those that directly release electrical energy (such as batteries and capacitors) or mechanical energy (such as flywheels, springs, compressed air, or water in a reservoir).

View More On Wikipedia.org
Recent contents Top users
  1. J

    Can Someone Explain How Nuclear Fuel Rods Heat Water in a Reactor?

    Hi, I haven't studied much nuclear physics and would be very grateful if someone could answer a few basic questions I had about fission in the fuel rods on how the water is actually heated in the reactor core: 1) I don't know if I have this correct but is it that the way the water is heated in...
  2. J

    Understanding the chemical process in a fuel cell

    Hello, I'm taking an energy class and I'll be giving a presentation on fuel cells. I was wondering if I could get some help understanding the whole process of the paper below. Unfortunately, I can't post the article because of copyrights. To summarize, it's a one compartment H2O2 fuel cell with...
  3. parazit

    Mass of the fuel consumed at the reactor each year?

    Hi fellows. I am dealing with the following question and any help to solve it will be a huge favor. Let us consider a nuclear power plant which delivers 100 MWe. The plant is based on a Rankine cycle, where the steam exiting the reactor is at 350 C and water exits the condenser at 20 C. The...
  4. OmCheeto

    Fossil fuel reserves and home heating

    Given that: When will fossil fuel reserves be diminished? "The new formula is modified from the Klass model and thus assumes a continuous compound rate and computes fossil fuel reserve depletion times for oil, coal and gas of approximately 35, 107 and 37 years, respectively." [bolding mine] 36...
  5. M

    "Y plus" calculator value for a fuel bundle

    Hi everyone, I am using a online y plus calculator to work out the y plus value for a fuel bundle. http://www.pointwise.com/yplus/ In regards to the reference length, I have been told by peers to utilise the hydraulic diameter using 4A/P where A is the cross sectional area, and P is the wetted...
  6. S

    Automotive Idling or turning the engine off?

    Hi all, I am aware that idling is fuel inefficient and a waste of fuel, but I guess that it is not always convenient to turn the engine off, since the turning on requires more energy than idling. So, I think that for long periods, turning the engine off is more fuel efficient than idling, but...
  7. Delta Force

    Using Fuel as a Combustion Engine Coolant?

    Some jet and rocket engines use their own fuel as coolant. Hydrocarbons have even been used to cool electronics and nuclear reactors. Would it be viable for a combustion engine to use its own fuel as coolant instead of water or another liquid?
  8. S

    Auto/Motor Designing a fuel tank, need advice

    Hello everyone, So, I want to make a fuel tank for a motorcycle with a glass window in it. I have seen a custom bike with a completely pyrex tank, so I know it's not impossible. My current questions are: Are there any important regulations for fuel tank construction which I will need to...
  9. S

    Hydrogen to AC -- From the Fuel Cell to the Grid

    Fuel cells quickly provide electricity from H2 when switched on. But what exact steps get to Grid voltage? Are there many small inverters, and if so, how do they keep the output in step? What sort of efficiencies are there?
  10. T

    I Can Mummies Be Used as Fuel for Steam Locomotives?

    There was this myth that in 19th century steam locomotives used Egyptian mummies as fuel for steam locomotives, but in reality how good would dried human flesh be as that kind of a fuel for locomotive compared to coal?
  11. joker1319

    Automotive "Engine fuel consumption map" without the torque possible?

    Hello, I am currently facing a problem. I'm on a project and trying to create an "engine fuel consumption map (engine torque / engine speed)" among other things. Unfortunately, the engine torque is not measured in my measurements. More specifically, the "actual engine - percent torque (OBD PID...
  12. mastermechanic

    How is fuel pumped in fighter aircrafts? (F-16 etc.)

    In fighter aircrafts manoeuvrability is at high levels therefore fuel tanks are exposed different operating orientations and positions so is the fuel inside. How do they ensure that the fuel is pumped properly? There is picture always comes to my mind when I hear fuel tank, a straw sinked in a...
  13. Chincha40

    B Hp/Kw required to move 1.5L/m of diesel fuel at 17.2 Bar?

    How much Hp/Kw required to move 1.5L/m of Diesel fuel at 17.2 Bar? Please note this is for a real life problem.
  14. R

    Void Coefficient: Why Is It Negative in US Reactors?

    Why is the void coefficient in enriched US reactors negative?
  15. M

    B When a star exhausted it's nuclear fuel

    What powers a star?
  16. M

    MHB Optimizing Fuel Usage on a Circular Route with Squares: A Mathematical Proof

    Hey! :o I am looking at an exercise that is formulated as follows: Finite number k of squares on a circular route. The whole fuel in all is enough for 1 circle. Show that there is a way to integrate the circle however the squares and the fuel are distributed. There is also the following...
  17. Mackenzie Cobb

    Why isn't tungsten used in nuclear reactors?

    Me again, with another potentially ignorant nuclear science question: Why isn't tungsten used to prevent meltdown in nuclear reactors? If tungsten has a higher melting point of tungsten is almost 6200 degrees Fahrenheit, and nuclear meltdown happens when the uranium fuel is some 5200 degrees...
  18. A

    Fuel cell mass flow rate magnitudes

    Hello, Can you tell me please the mass flow rate of hydrogen and oxygen per unit of area of electrodes in fuel cells? Or if you have information on the mass flow rate of hydrogen and air per volume of fuel cell stack? I understand this may vary, but I am looking for publications or other...
  19. Andrew broome

    B What can be used to propel something in space without fuel?

    To specify, by fuel I mean fossil, nuclear, chemical and pressurized air. Want to build and design a satellite for my daughter with a camera in it (goPro) with an antenna to be able to view anytime she likes. Want to do a hexagonal approach with solar cells only for power. Want to power the...
  20. Timothy Schablin

    What is the fuel weight required for a Mars mission?

    I'm curious of what the weight of fuel would be to land and take off from Mars would be? I know it all depends on payload, but would it even be possible to blast a rocket from earth, with enough fuel to get to Mars, land on Mars, blast off from Mars, and then return to earth? My guess is that...
  21. chemisthypnos

    Automotive Hydrogen Car Fuel Tank: Preventing Permeation & Valve Check

    How do hydrogen powered cars prevent the permeation of hydrogen through the valve used to fill the car's tank with hydrogen? Is a regular check valve used or is the valve special in some way?
  22. G

    Maximizing rocket velocity - shoot fuel at once, or slowly?

    I stumbled upon a 3-year old article from Wired that poses this question on rockets: Suppose I have two rockets with a mass M and fuel mass m. Rocket A shoots all the fuel at once (again, like a nuclear propulsion engine) with a fuel speed of u and rocket B shoots two blobs of fuel—first a shot...
  23. C

    What is the combustion efficiency of liquid fuel rockets?

    How efficiently is the fuel burned in a typical liquid fuel rocket engine? I've heard numbers ranging from 95% to below 50%.
  24. B

    Calculating US Nuclear Reactor Fuel Supply

    Homework Statement i have a little confusion with this problem the problem is asking me to calculate "how long could you fuel the 99 current reactors in the US?" Homework Equations The problem is asking for an evaluation of fuel energy value in comparison to demand edit:(i forgot to add that i...
  25. C

    How to calculate Fuel Mass Flow Rate

    I'm having a brain storm, If I have an 8 cylinder 4 stroke engine running at 4000 rpm over a 10 minute test and it consumes 4.4 Kg of fuel, then is the fuel mass flow rate as simple as the 4.4 Kg divided by the time to give me an answer on Kg/sec ? Thanks,
  26. A

    Could a spacecraft refuel from the atmosphere?

    https://phys.org/news/2018-03-world-first-air-breathing-electric-thruster.html If it dipped into the atmosphere temporarily on an elliptical orbit, could the air gathered be stored for a long flight? Then maybe get more fuel from another planet's atmosphere or moon for the return trip?
  27. N

    Fluid Mechanics: Choosing a fuel line diameter for a required pressure drop

    Homework Statement [/B] Homework Equations - The pressure drop equation. [/B]The Attempt at a Solution
  28. Y

    Nuclear fuel cycle boc eoc boec eoec?

    Hello everyone! I have my first question in physics forum... When I read some reports I found those terms that can not be understood... 'BOC', 'EOC', 'BOEC', 'EOEC'... BOC and EOC are used frequently and I know those terms shortly but not exactly... but I can understand boec and eoec and...
  29. Ranku

    I Energy efficiency of nuclear and fossil fuel

    Can anyone give a percentage comparision of efficiency of energy conversion in nuclear fuel and fossil fuels like oil and coal?
  30. srinaath

    Why do we need to supply air to the cathode of a hydrogen fuel cell

    I am trying to understand the working of simple hydrogen fuel cell. We have anode (negative terminal), cathode (positive terminal), catalyst at anode to separate negative and positive ions of hydrogen atoms and electrolyte which allows only positive ions. We will be sending hydrogen fuel at...
  31. E

    Chinese fuel reprocessing plant, store Kr-85

    Hello everybody! Areva is supposed to build a plant in China to reprocess spent nuclear fuel (agreement hoped in Spring 2018). I should like to remind that the radioactive 85Kr fission product, which stays in the fuel rods until they're opened, can be stored easily until it has decayed, as I...
  32. G

    How Are BWR Fuel Assemblies Managed and Composed?

    Hi, now I watched a video that I knew before but this time I kind of thought I want to know for sure. The video is about fuel change in a BWR type reactor, now I have question to someone who knows about this or maybe has worked with it, are the rectangular fuel assemblies seen in the video...
  33. P

    I The physics of a missile with uniform rate of fuel loss

    Hello everyone! I'm at a loss trying to figure out the specific force that pushes a missile at rest off the ground, to the high sky. Considering a missile with constant mass, and an independent initial total fuel mass. The rate of fuel mass being expelled out of the missile is constant, in...
  34. J

    Microbiological Fuel Cell: Negative Voltage

    Hello! I've been working on a few soil based MFCs and I have been monitoring my voltage and energy output for a week now. I've made the electrodes by covering stainless steel metal meshes with activated carbon using epoxy. I've gotten some funky results as attached. As you can see... the...
  35. T

    Regression rate of fuel in rocket nozzle

    So we have: stability for n < 1 instability for n > 1 I assume to get the time growth, I have to integrate the above first eqn. However I also get ln(δpc) at the LHS from the integrating. However the above equation for time growth removed that ln(δpc) and thus I can't...
  36. King_Silver

    Sustainable Energy Calculation for Fossil Fuel Mix

    Homework Statement Homework Equations No equations used (to my knowledge). Just arithmetic and understanding of what is being asked. The Attempt at a Solution Was wondering if my solution/approach to this question is correct or not? I don't have any answers to compare it to so any...
  37. Kirk Truax

    BWR Fuel Assembly Question -- Why do BWRs have shrouds?

    Hey all, I was wondering if anyone could help me with a basic BWR question. Why do BWRs have shrouds? From what I've been able to find, this is a for "uniform cooling" but that's about it. My guess is that there are some thermal hydraulic benefits around maintaining nucleate boiling. Is...
  38. hilbert2

    Flame in a background atmosphere of fuel

    In combustion science, typical flames that are studied are premixed or diffusion flames, where a stream of methane, propane or some other fuel is released to an atmosphere of air or oxygen and ignited. Another scenario is a "pool fire", where a puddle of volatile solvent is burning in air and...
  39. bbbl67

    Automotive Gasoline Fuel Cells: Energy, Weight & Efficiency

    I understand that there is some research going on into gasoline (i.e. petrol) fuel cells (as opposed to the more typical hydrogen or alcohol fuel cells). How much energy can be released through a gasoline fuel cell, as opposed to simply burning it in an internal combustion engine? Will more...
  40. J

    Could UV lasers be used to split CO2 and H2O?

    I was wondering whether intense UV light, tuned to the correct wavelength, could be used to split carbon dioxide and water molecules as a first step towards synthesizing liquid fuels.
  41. O

    Unit cell conversion and shape of fuel pellet

    As you may know, below is the conversion process of square unit cell into circular shape in order to calculate the thermal utilization factor (f) for a lattice. As far as I know, it is really difficult to make a simulation for which a lattice is constructed as a circular fuel and square...
  42. mheslep

    Fuel rod leak (failure) frequency

    After reviewing some old threads (e.g. here), anecdotally I see that fuel rods do suffer failures on occasion, but it appears not very often, as is intended. My question is, why not more frequently? Given a power reactor neutron flux of 1014 n/cm2-s, it seems like every atom in the cladding...
  43. J

    Calculating Free Energy in Nuclear Fuel Reactions

    Homework Statement Calculate how much free energy in 1kg of nuclear fuel, assuming the most common reaction at a nuclear plant is 235U + n ---> 139Ba + 86Kr + 11n + 176 mev Homework Equations E= mc2 ? 1mol of 235U = 16.5 KJ The Attempt at a Solution Do I need to balance the equation? How...
  44. I

    How to calculate the efficiency of a fuel engine

    Homework Statement [/B] Im trying to find the efficiency of a gasoline engine regarded as a control volume. Am I right to use the HV as total energy input into the system? Assuming the enthalpy of formation of the fuel can't be found. I am really wondering if enthalpy of formation equals the...
  45. D

    Maximum mass value possible to fuel a spaceship

    Homework Statement We are given that a spaceship converts mass directly to light (emitted backwards) in order to accelerate. If an energy mc^2 has been converted to light ( from the Earth's reference frame) then what is the final speed of the ship (w.r.t. Earth) if the ship's rest mass is M and...
  46. infinitebubble

    I Micro Black Holes and Dark Matter as fuel for spaceship?

    I've been reading several ideas postulated by some researchers using either Dark Matter and or a micro Black Hole as energy sources to power a future spacecraft . 1) using dark matter as fuel to power a spacecraft by taking dark matter into a cavity and shrinking it to critical point using...
  47. D

    Getting rid of fuel cell / flow battery membrane

    I am aware of laminar flow but would like to look for some other ways. Is it possible to block ions from flowing in the "wrong" direction by applying a magnetic field to the electrolyte and let neutral molecules pass through?
  48. G

    I need an advice to prepare an alternate renewable fuel

    Hi! Can someone please guide me as to how can i convert inorganic waste to alternate fuel which can be used instead of regular fossil fuel or atleast can be blended with fossil fuels to prepare cleaner fuels.
  49. N

    Fuel Cells for Isolated Electric Generation

    Hello, I am researching about fuel cells that use Ethanol as a fuel, because I want to buy a equiptment of approximate 5 Kw (Electric) that uses Ethanol as a fuel for electric generation in anyplace, where yet there is not supply of electrical Energy by wire. Have you heard anything about this...
  50. P

    B How do Neutrons and U235 Nuclei get out of the fuel rod

    I understand that there are fuel rods, water control rods. I also understand that fuel rods are metal tubes filled with special U235 pellets. Finally, I understand that water slows the neutrons down enough to collide. How do the neutrons and U235 nuclei get out of the metal encased fuel rod...
Back
Top