Combustion Definition and 348 Threads

Homework Statement Biomass with a heating value of 15 MJ/kg burns in steam generator at a temperature of 1200K and all of the heat is given to the steam at a temperature of 600K. The ambient temperature is 300K. Calculate exergy of combustion products, steam and the loss of exergy.Homework...

Hello friends, The balanced chemical equation for the combustion of carbon is: C(solid) + O2(gas) -> CO2(gas) Now, the lower and higher heating value of hydrocarbon fuels (such as methane) exists because in the LOWER heating value, you are subtracting away the latent heat of vaporization of...

Dear PF Forum, I have read this link in Wiki. But I don't understand what it means. Can someone help me? https://en.wikipedia.org/wiki/Heat_of_combustion A: Heat of combustion of CH4 is 50.09 MJ/kg https://en.wikipedia.org/wiki/Standard_enthalpy_change_of_formation_(data_table) B: Enthalpy of...

Hi guys, I want to design a gas burner and combustion chamber. I use natural gas as fuel. I want to control air to fuel ration, so air flow has to control. I have an air compressor as air flow source. Clearly, it's needed a mixture tube before the combustion chamber. Now I have some...

I'm not a chemist, but I'm interested in it. What I am trying to understand is why its so hard to get energy from fossil fuels without being able to sequester the carbon released in some kind of liquid form. I understand how piston engines use the expansion of gases (through combustion) to work...

hi, i want to ask about 4 time combustion engine torque. in my example we simulate a single cylinder gasoline 4 time engine which works 1000-4000 rpms and always have same fuel and air mixture in cylinder and so same burn pressure in each power time. these are the rules of question now i want...

Like in a topic. I just got this question and I am looking for some help. I found this one http://wikieducator.org/The1stLawofThermodynamicsLesson5 I don't know, is the heat of combustion is the same as entalphy?

Hi, I'm currently doing a small racing game where I allow players to tweak their car's engine (control number of cylinders, cylinder bore/stroke, turbo chargers, etc). I've understood the very basics of how combustion engines work but I'm still struggling on how to calculate engine torque...

let's take the combustion of an hydrocarbon CH4 + O2 = CO2 + H20 the products of this reaction is: 1) large heat 2) large amount of gases 3) high kinetic velocity of gases 4) heat of gases what is the exact thing we take advantage in internal combustion engines? the large amount of gases...

Hi Everyone. I am trying to simulate a rocket combustion chamber. The question I have is this. Is the ignition (by any means) in the rocket combustion chamber only used for increasing the temperature of the cryogenic propellant to a state where it can ignite and burn? If you are using an...

hello! what is the atomic mechanism of combustion that makes it so exothermic? what makes O2 so reactive with hydrocarbons for example and why is the reaction exothermic? thanks

Hello guys, I'm currently working on a car simulation just for fun, but I'm stuck... The force to move a car is generated by burning fuel ( to be more percise, diesel or gasolin). But there are more variables: Pressure (i know this because of turbos and such) amount of fuel amount of air (or...

Lets say if i have a bell nozzle rocket engine such as this one : http://www.braeunig.us/space/pics/fig1-04.gif and inside the combustion chamber i have an average pressure of around 300 psi. If i wanted to feed in liquid fuel into it while the fuel pump is only able to supply 100 psi of fuel...

Homework Statement there is an expandable container with 1m3 of hydrogen and 1/2 m3of oxygen at stp. the gas is ignited.what is th final volume if there is no heàt lost and the pressure outside the container is 1atm? assume complete combustion Homework Equations other than the ideal gas...

Question: is it possible to have any of the following - 1. Steam engine in a car 2. A steam internal combustion engine 3. A hydrogen internal combustion engine Background info Hi all, I am working on a fiction short story for fun. It is set in a parallel universe so history and a few...

Why does or how does combustion of fuel and air in a combustion chamber in a brayton cycle is idealized by a CONSTANT pressure. I remember that in a diesel cycle, it was idealized by constant pressure because as P increases by ignition but the volume increase offsets this increase. However, in...

hello we know that there is 42% limitation in the efficiency of internal combustion engine, thermodynamically calculated by Carnot and we can never overcome this can someone explain me in few simple words why this is true? also, does this apply to the energy from internal combustion to...

can anyone suggest me the sites where i can find the methods to improve the efficiency of IC engines?

Would it be possible to build an engine that runs primarily off a petrol but has a steam engine that captures all the heat lost from the combustion (70%) and applies it towards powering the engine? Looking for ideas, opinions and attitudes on whether or not it is a practical idea.

hello! I tried to find online but no luck can you tell me please what is exactly the energy from a combustion? let's say of 1 mole of gasoline is it mechanical waves? it is light? is it temperature? I need to know the details, how much of it in the various types of energy, and what exactly...

hello I am interested to know in detail, how internal combustion engines work dynamically, ie. as the demand for speed and torque change what happens exactly? I know that when we want more speed/torque, we push the gas pedal, but what happens exactly between that moment and the increased rpm...

Homework Statement The efficiency of a heat machine is ##E=\frac{Q_2-Q_1}{Q_2}## where Q2 is the heat inserted because of the explosion and Q1 is the heat that leaves through the exhaust. It says in the book that E can be derived from the volumes ratio V1/V2: $$E=1-\frac{1}{\left(V_1/V_2...

Hi there, Could someone explain to me why fossil fuels, such as coal and oil, produce fewer particulate matter emissions than natural gas? Also, how would you expect the combustion temperature of these fuels to affect particulate emissions? Would a higher temperature lead to a more complete...

Hello everyone, i need to find reported transfer functions of internal combustion engines for a project, i would appreciate the model of a four cylinder engine. If anyone knows about a book or some article which i can use, please let me know. thank you very much. the topic is related with...

Can an electric arc(such as this one http://upload.wikimedia.org/wikipedia/commons/7/7a/Electric_arc.jpg ) cause a combustion or fire if a 91 percent alcohol solution is sprayed on it?Thanks

Homework Statement For the following calculations, assume a typical electric car will need to apply a constant forc of 165 N to maintain a typical highway speed of 100 km/hr (27.7778 m/s). A: What power (watts) is needed to maintain this speed? B: What energy (Joules) is needed to travel 100...

< Moderator Note -- Thread moved here to Homework Help forum > One volume of CH4 is mixed with V volumes of air (78 vol.% N2,21 vol.% O2,1 vol.% Ar) at 1 atm and 25°C; then the mixture is ignited. Find the temperature of adiabatic combustion (the adiabatic flame temperature). The volume of air...

Hi am a bit stuck on understanding how these two correlations can be similar I am wondering if anyone can ahead any light Can anyone solve Correlation for heat transfer by natural convection from a horizontal pipe to atmosphere is; Nu = 0.53Gr^0.25Pr^0.25 Nu = hd / k Where, Gr =...

Hello, Can the heat of combustion only be found experimentally? I am looking on this page at the heat of combustion of ethanol http://www.ausetute.com.au/heatcomb.html and I see that ##\Delta H^{o}_c = 1368 \hspace{0.05 in} kJ/mol##. But if you calculate from its constituents ##C_{2}H_{6}O...

just how effecient is the internal combustion engine. please tell me(any/all you know/ or can find online), efficency of an average engine, best achieved ever effecincey(ideal scenario), and the maximum theoritical efficency.. i am talking about energy put in vs the amount that is useable.(by...

i'm trying to model the combustion of a pressurized gas (nitrous oxide) inside of a paraffin ring. What I'm trying to figure out is the amount of paraffin that will be burning per unit time. What I'm assuming is that the gas is totally covering the inside of the wax ring and Ideal Gas law. I'm...

I always like to be specific when talking about "energy released". It is too vague for me, there is what to specify there. Take the example of the ATP molecule. When you break the bond, it will be the phosphate groups repelling each other, so it will be their kinetic energy that results in...

I have been interested in (the concept of) large frame industrial combustion turbine supercharging since the early 90's. However, although I believe the concept has merit and has been done successfully in at least one location nearly 3 or 4 decades ago, the concept has not evolved since...

Homework Statement according to the model ans, the volime of oxygen produced is 25x 24 dm^3 ... where does the 25 come from ?? or someone can show me other step of getting the ans ? thanks in advance! according to the model ans, the volime of oxygen produced is 25x 24...

Homework Statement Which would have the most negative heat of combustion? Consider only the best conformer. cis-1,3-dimethylcyclohexane trans-1,4-dimethylcyclohexane Homework Equations The more negative the heat of combustion, the more exothermic the combustion. We are...

Question: 1 kmol of gaseous methane (CH 4) is mixed with the correct amount of air in a closed vessel. The pressure and temperature of the mixture are 1 bar and 298 K respectively. The mixture is ignited. Estimate the adiabatic temperature of combustion. Answer: ~2743 K OK, so first I...

In this diagram,non-ideal combustion in a diesel engine takes-up a lot of the fuel energy. Why is this so? Also intrigues me that there is a lot more non-ideal combustion at low load than higher loads. Is this because the diesel engine operates with a lower compression ratio at lower loads? This...

For a ramjet engine, combustion occurs at a finite Mach number M. If we know the ambient conditions like free stream Mach number and pressure and the ratio between the stagnation temperature at the inlet and exit of the combustor, how can we derive the thrust? How can we incorporate the...

I've heard that fire creates a vacuum due to the consumption of oxygen. Obviously, combustion results in other gases being released (CO2 and H2O vapor). Some have said that there is no vacuum; others have said there is in fact a partial vacuum. I assume that it depends on the relative...

Hello I am interested in self-teaching basic combustion concepts. Is there a good textbook available that introduces combustion at an undergraduate level for someone with high school chemistry knowledge? Thanks very much

http://www.huffingtonpost.com/2013/10/01/frank-baker-spontaneous-combustion_n_4024833.html Frank Baker faced death while earning two Purple Hearts in Vietnam, but the scariest moment of his life came in June 1995. Baker was in his home in Vermont, when he suddenly burst into flames, an...

Homework Statement The sun has a mass of 2*10^30kg and gives off energy at a rate of 3.9*10^26 watts. If the source of the sun's energy energy were ordinary combustion of methane how long will it last. Homework Equations delta Enthalpy of the combustion of methane is -802 kj...

$$C_{5}H_{12} + O_{2} → ... $$ What would be the product? Please show in steps how you're getting your answer, and what oxidation state you're using for C, I don't understand why Carbon and Hydrogen are bonded in this ratio, please explain. Also, please provide any advice/strategies on...

Hello everybody, I am working on the whole vehicle calculations, engine, brakes, suspension and engine simulation, using that software, take a look: http://www.speed-wiz.com/calculations/engine-simulation/engine-simulation-conditions.htm That software, you input the values at the top...

what is difference between rapid combustion and turbulent combustion

Hello, Please help me with the following problem. Homework Statement 0.10 Liter of Methane (CH4) gas, at a temperature of 25C and pressure of 744mmHg, react with Oxygen (O2) gas, at constant pressure. The heat released during the process is then transferred to an "ice...

Homework Statement Given the following enthalpies calculate the molar heat of combustion of C2H2. Heat of formation of liquid water: -285.8 kJ/mol Heat of formation of C2H2 (gas): -26.7 kJ/mol Heat of formation of CO2 (gas): -393.5 kJ/mol Homework Equations Heat of combustion is...

Hello everyone! I have a question: Let's say we have a 6g sample of a compound that has C, H and O. This sample is burned with excess oxygen. I want to know if it is possible to recover the mass of O in the original compound from the mass of H2O and CO2 that will be produced (from...

How do I tell if a certain species will not react or combust with O2 gas regardless of the conditions? I am trying to deduce which species will have standard enthalpy (or entropy or Gibbs' free energy) of combustion of 0, besides obviously O2 itself. e.g. CO2, H2O, perhaps ...?

Hello. I've gone round and round in my studies of engines and related technologies and I've come to the point where I would benefit from a better understanding of how combustion reactions occur and are sustained in gasoline engines. I have been looking for some basic introductory level...