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Questions tagged [combustion]

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18 views

Input Parameters for Combustion Chamber

I am doing a column breakup study. But for a better study I need air velocity, turbulence intensity (not primarily needed though),temperature, pressure and same parameter for injected liquid fuel. I ...
0 votes
0 answers
31 views

Why do engines with cylinder offset not suffer from increased frictional losses on the compression and exhaust strokes?

I recently watched the D4A YouTube video on cylinder offset, and for the most part it makes sense. Longer power and intake strokes, lower frictional losses on the power and intake strokes, greater ...
2 votes
1 answer
57 views

How much coal is needed to generate electricity for 1 person?

In one month a person uses $852$ kWh of electricity. Using a fossil-fueled vapor power plant, find how much coal is needed for one person. The assumptions are: Boiler efficiency of the Rankine cycle ...
0 votes
4 answers
2k views

Throttle position as a function of engine torque and speed

In the figure attached showing the throttle position versus an IC engine produced torque, I didn't understand why does the torque value at a specific rpm vary for different throttle positions. My ...
0 votes
0 answers
25 views

Enthalpy of Fuels

I am running some analysis on an engine cycle through matlab using TMATS with Cantera. I am looking to change the fuel from the default to a blend of ammonia and hydrogen. In order to do this I have ...
0 votes
1 answer
32 views

Why is the compression considered as isentropic in Otto cycle?

We know the ideal Otto cycle is modeled by the two ideal processes isentropic (compression and expansion) and isochoric (heat addition and heat rejection). But why the compression and expansion ...
0 votes
0 answers
10 views

How estimate the error of chemkin 2.55 results?

I've been using chemkin 2.55 for preliminary calculations of premixed laminar H_2 and CH_4 combustion and in some of the calculations, the solver fails. There is a way to hypothesize the calculation ...
0 votes
0 answers
11 views

Need for diaphragm carburetors in small internal combustion engines that run on gasoline

I have seen that hobby internal combustion engines that run on gasoline always use diaphragm carburetors instead of the very simple carburation system used by glow engines that generally consist only ...
0 votes
0 answers
33 views

Unstuffed to Stuffed Two Stroke Engine

I'm working on a Puch e50 Engine. The original engine used an unstuffed crank that had bushings instead of bearings. I've rebuilt the engine using new seals, bearings, and an aftermarket stuffed ...
1 vote
3 answers
3k views

How do you prevent ignition of the gas-air mixture before it reaches the burner nozzle?

I believed that the flame propagates over the place where fuel contacts the oxygen. If it contacts a fule+O2 mixture, the mixture inflames as well, and so on and on and on until there is no more ...
0 votes
0 answers
26 views

Would there be a flame front in this case of combustion

Suppose a piston enclosing an amount of air-fuel mixture and then this piston compresses the mixture to the point of auto ignition, if every part of the mixture ignite simultaneously is it safe to say ...
0 votes
1 answer
122 views

NOx emissions in diesel engines

What are the specific challenges and potential solutions for reducing NOx emissions in diesel engines without sacrificing fuel efficiency, considering the trade-offs between various aftertreatment ...
1 vote
3 answers
155 views

If it is more fuel efficient to mechanically inject gasoline into a high compression cylinder, why is it not done?

By the thermodynamics of the internal combustion engine (Carnot cycle), the higher the compression ratio, the more mechanical work is derived from the gasoline burned. So why is it not common practice ...
4 votes
3 answers
581 views

What is the maximum possible compression with fuel injection in a gasoline combustion engine?

Maximum possible compression in a gasoline engine was originally determined by knocking in engines with carburetor. With fuel injection the fuel could be injected after compression and thus eliminate ...
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0 answers
49 views

How much CO2 is produced by wood biomass under complete combustion?

If I have a one tonne (equivalent to 1.167 m3) of residual wood product used in a suspension burner at 3% moisture. The wood consists of a mixture of softwood by-products. How much CO2 would be ...
-1 votes
3 answers
124 views

Combusting engine braking: is part throttle more effective than no throttle?

A counterintuitive question. An engine when in overrun generates a braking torque. This is generally considered to be because the engine is working as an air pump past a closed throttle. However that ...
0 votes
0 answers
272 views

Are internal combustion engine more efficient than steam turbines

From what i understand the indicated thermal efficiency of an ic engine is measured at the fly wheel and is the measure of the amount of thermal energy being converted to mechanical energy please ...
1 vote
0 answers
175 views

Fastest possible mean (peak?) piston speed on a Diesel engine

On a Diesel engine running distillate fuel (the kind you run in cars, SUV's, trucks, trains, boats, and smaller ships), what are the theoretical and practical limits to maximum mean piston speed you ...
0 votes
0 answers
79 views

How to calculate the amount of fuel required and time to preheat a furnace's combustion air to 850 C

I am designing an incinerator to combust MSW producing a flue gas of 1000 °C. A requirement of the furnace is that the air inside must be preheated to 850 °C through the use of auxiliary fuel burners ...
0 votes
0 answers
134 views

What methods should I use to calculate the size of a moving grate incinerator

I have been tasked with calculating the size of a moving grate incinerator for a college project. I have calculated the mass and energy balances for the waste to be burned on the grate, but I am ...
0 votes
2 answers
101 views

Why this engine can work without a timing belt? [closed]

Is it possible that this tiny engine work without timing belt? I have seen the schematics of it and it pretty much rely on holes in the middle of piston to get the hot gas out whereas the ignition is ...
2 votes
1 answer
1k views

Out of the three types of Stirling Engines, which one is the most efficient and delivers the most amount of power?

I was thinking that the beta Stirling engine would be the most efficient as it has a displacer to block heat transfer from the hot to cold regions in between thermodynamic cycles. However, I heard ...
1 vote
2 answers
1k views

How can I turn home gas (LPG) from liquid to gas?

"LPG" is the term used here for a mixture of Propane & Butane sold for public use. The exact ratio varies depending on where you buy it and I think also with the season and is not known to me. I ...
2 votes
4 answers
1k views

Is high pressure combustion hotter than atmospheric pressure combustion

let's say i have the same quantity of coal and air. Will the combustion achieve higher temperature if the air is under pressure?
5 votes
1 answer
415 views

How do I choose a blower design for an induced draft brick kiln?

I am responsible for a brick kiln in the Punjab province of Pakistan. My government requires all brick kilns to be upgraded to match recent new standards, which include the addition of a blower near ...
2 votes
0 answers
42 views

Comparing EPA emission limits between wood stoves and wood furnaces

Emission limits set by the EPA were updated in 2020. Currently, "Wood-burning stoves" are allowed 2.5 grams/hour of smoke emission [1]. On the other hand, "Wood-burning forced-air ...
1 vote
1 answer
175 views

Theoretical maximum pressure from combusting LPG

I am curious how to find or estimate the theoretical maximum pressure that the combustion of a LP gas, such as propane, can produce inside of a constant volume, such as in a cylinder. I know what the ...
0 votes
1 answer
80 views

Magnetohydrodynamics, ionizing combustion exhaust then converting its kinetic energy to electricity

I am trying to understand how to make generation of electrical power more efficient by using Faraday's law to directly convert the kinetic energy of the ionized or easily ionizable exhaust gases of ...
3 votes
1 answer
97 views

Can we currently achieve 55 MPG on Non-Hybrid vehicles using internal combustion engines?

With recent debates, one frequently hears that it's currently not possible for car manufacturers to meet the 55 MPG energy efficiency rating required by 2025. So, is there something physically ...
1 vote
0 answers
153 views

A Variable Valve Timing (VVT) engine with exhaust GT added, with and without Turbo Charger applied to the crankshaft?

This topic is the follow-up to the original topic: Why are turbo compound engines not more widely used? Why are turbo compound engines not more widely used? Please, do understand that I am a pure ...
2 votes
1 answer
69 views

Ash size particle dependency of initial coal particle size in fluidized bed combustors

I'm looking for information on coal ash size in fluidized beds. How dependent is it on the initial coal particle size? Would I expect ash from 5mm coal particles to be significantly larger than ash ...
1 vote
2 answers
106 views

What is the purpose of combustor in a gas turbine

I have read online that a gas turbine converts the chemical energy in the fuel gas to mechanical energy of the turbine blades. The way I see it, because of this hot air one would have to go for heat ...
1 vote
1 answer
41 views

Can I increase the range of a howitzer by using more propellant?

The muzzle velocity of a firearm can, all else equal, be increased by lengthening the barrel of the weapon which can theoretically be extended up to the point that friction and air resistance would ...
3 votes
2 answers
1k views

Why is soot produced in diesel exhaust, since diesel runs lean?

Since diesel runs lean, why is soot produced in diesel exhaust? Soot is carbon particles due to incomplete combustion. But, since diesel runs lean with plenty of oxygen, why does this happen?
8 votes
5 answers
3k views

Why do some diesel engines run on diesel fuel and others on fuel oil?

Trucks and smaller vehicles with diesel engines run on diesel fuel which looks more or less like kerosene - less flammable than gasoline, low viscosity liquid. However larger diesel engines like this ...
2 votes
1 answer
42 views

Recovering mechanical energy from natural gas water boiler

Is there any heat energy lost to the mechanical force of pushing a piston in a combustion engine? In other words, would a natural gas burning as a flame produce more heat than the same amount of ...
1 vote
1 answer
950 views

Trouble with Valveless PulseJet

My friend and I are working on building a valveless pulsejet out of sheet metal. We initially built a small one (a few feet in length) using the below dimensions: The issue was that we were unable to ...
3 votes
3 answers
3k views

Preheating Diesel before injection?

Significant amount of heat is lost from an engine by various means, so to recoup the energy, is it possible to increase efficiency via heating of diesel fuel prior to injection using waste engine heat ...
-1 votes
1 answer
1k views

Calculating Mass Fractions of a Hydrogen and Oxygen Gas Mixture Pre Ignition

I am trying to calculate mass fractions of a Hydrogen Oxygen gas mixture as a function of equivalence ratio before ignition. My work is the following: Equivalence Ratio: $$\phi=\frac{FA}{FA_s}=\frac{\...
2 votes
1 answer
172 views

Effect of Pressure on Combustion efficiency (of hydrogen) in excess air

Can somebody explain relation between combustion efficiency and pressure in lean mixtures using any kind of chart or mathematical equations? At first glance I thought, combustion efficiency increases ...
2 votes
1 answer
922 views

Engine Combustion Cylinder Wall Thickness

Been referencing this website for some time but now need to seek specific help. I am not an engineering student but rather a DIY hack who loves engineering and machining neither of which I am ...
0 votes
1 answer
81 views

What are the non-practical features of a sterling engine that cause the internal combustion engine to be used instead?

What are the non-practical features of a sterling engine that cause the internal combustion engine to be used instead (in a car)? (e.g. price, size, the power to weight ratio, etc.) Can you name any ...
1 vote
0 answers
50 views

Search for comprehensive term for plants with heat generation with heat storage and operating states

My master thesis deals with systems with several operating states that generate heat and store it in a heat storage. Thereby I analyze combined heat and power plants with combustion engines, but also ...
14 votes
3 answers
4k views

What happens when you put the wrong type of fuel in an internal combustion engine?

What happens to the working of petrol engine when it is emptied and filled with diesel or to a diesel engine emptied and filled with petrol? Will the engine be able to operate and, if not, why not?
1 vote
3 answers
16k views

How to filter outside air during wildfire to safe breathable level?

I've had an experience of having outside air heavily polluted by wildfire smoke, and now I'm reading up on the wildfire happening in Southeast Asia. When the air outside got too polluted to breathe, I ...
1 vote
2 answers
187 views

Where the Water Have Gone from Engine from a Combustion Process (C8H18+12.5O2==>8CO2+9H2O)?

During studying engine's exhaust as I asked here, I have to go far. The thing I though is quite simple, the fact is complicated. Thence I knew that there is water produced in combustion process. The ...
1 vote
1 answer
90 views

Why to compress the hydrogen + air mixture in Hydrogen ICE engines when combustion efficiency of hydrogen at 1 atm is already high?

ICE Engines are designed to burn the fuel and air mixtures at high pressures to increase the combustion efficiency. But hydrogen combustion efficiency is already high at 1 atm and at constant Volume ...
1 vote
0 answers
225 views

Measurement of ICE torque

I'm seeking a precise description of engine torque. We talk about torque in terms of the twisting force that the piston exerts on the crankshaft with a radius equivalent of the rod throw. Assume these ...
3 votes
3 answers
65 views

Advice on simple spark ignition system

I'm looking for any tips on a simple and cheap means of generating a regular spark for ignition of propane in air, could be electrical or other but needs to be simple and fairly reliable. Criteria ...
1 vote
0 answers
24 views

Heat of Combustion, Vaporization tables

It's my first time posting on this specific forum. I hope I'm doing this right. I am currently modeling fire spreading through different buildings via FDS, but I lack the properties of the materials ...