Combustion of Liquid and Gaseous Fuels

Combustion of Liquid and Gaseous Fuels

  • Kamil Duda added an answer:
    What is most effective; EGR, or water injection, to reduce NOx, and what are the reasons for either one?

    Nowadays, a lot of action that making by researches to reduce the NOfor make our life free from the pollution. Therefore, the NOx will be reduce due to decrease of temperature in internal combustion engine and which one is more effective?

    Kamil Duda

    I will share with You with another issue. Fuel in CI engines ignites because high pressure and temperature conditions, water introduced into combustion chamber collect heat and deteriorate ignition parameters making fuel combustion harder to obtain.

  • Michael Pfitzner added an answer:
    Is there any fuel injector that can handle supercritical fuel injection into the combustion chamber?

    Is there any fuel injector that can handle supercritical fuel injection into the combustion chamber?

    Michael Pfitzner

    The thermodynamic state of the fluid (supercritical) has to be separated in mind from the chemical fact that diesel fuel cokes at high enough temperature. Does the needle not lift due to coking? Then the reason is chemical and not thermodynamical. There are many diesel fuel injectors which operate at supercritical conditions (regarding pressure).

    If the fuel gets too hot due to heat transfer from the combustor, you need to use an injector with sufficient thermal insulation. Such injectors are used in gas turbines (e.g. Parker-Hannifin). If diesel fuel gets too hot inside the injector, there is little you can do against the coking. Partial cavitation can help to keep the injector holes clean.

    What type of combustor are you using? Internal combustion engine like or gas turbine like or industrial burner like or something else?

  • Kamal Nasreldin Abdalla added an answer:
    How does mixed air & fuel ratio from carburetor affect the reading of flame speed obtained through Ion Probe Testing on Four Stroke Engine Model?

    Ionization probe contain signals that obtained in auto ignition zone and in burned gas at different amplitude. Obtained probe current-voltage characteristics showed that in auto ignition area the current to probe is formed by the drift of positive or negative ions, depending on the polarity of bias voltage.

    Kamal Nasreldin Abdalla

    In an engine using a carburetor ignition starts at the spark plug and the frm there flame will spread through the mixture of fuel and air. The speed or intensity of the flame depends on the Air/Fuel ratio. The fastest speed will occur if this ratio is soichiometric . If the ratio becomes very rich or very poor the rate of combustion will slow down.

  • Hanasoge Mukunda added an answer:
    How can I define a flame in numerical combustion?

    I am running an opposed jet case, where a stream of fresh reactants is opposed to a stream of burnt products. I am looking at the effects of stratification on the flammability limits of methane. 

    In some cases, in the reaction zone, the heat release is about 10^3-10^4 lower than compared to my reference case, which is far from the lean or rich flammability limits. Since I am sitting on or close to those limits, it is important for me to define one (or multiple) parameter for which I can say that the fuel is indeed burning.

    Here is my reasoning right now, but it might be incomplete or even erroneous. To check if the fuel is indeed burning, I have been looking at the distribution of key radicals. If the mass fraction of say H2, does not have peak in the reaction zone and only diffuses from one stream to another, then I can definitely say there is no flame. But a contrario, if there is a peak, can I definitely say there is a flame? And how big does this peak needs to be compared to its corresponding value in the reactant and products stream? (I am guessing at least one full order of magnitude). 

    If there is a standard definition of a flame in numerical combustion, please share it, preferably with an attached reference. 

    Hanasoge Mukunda

    The problem needs to be defined more precisely  before you can receive a useful meaningful answer. Please define the stoichiometry of the fresh mixture, temperature of burnt products that you are setting in your calculations of OJDF.. There is a  golden principle (not so golden though!) hat minimum flame temperature is about 1000 C. If this helps do use it. If not, you need to define the problem in some detail.

  • Maqsood Iqbal added an answer:
    How can I find average temperature in situ burning at sea water for heavy crude oil?

    I need to in situ burning temperature range

    Maqsood Iqbal

    Should be the same procedure, considering a certain temperature gradient within the water table/bed.

  • Siva Kumar added an answer:
    What are the effects of volumetric efficiency on combustion temperature?

    As is known, evelating the intake temperature can reduce volumetric efficiency in diesel engines. Likewise, boosting intake pressure can increase volumetric efficiency. 

    Higher volumetric effcinecy means stronger thermal capacity of in-cylinder mixutre. Hence, it is supposed that lower increase of in-cylinder temperature is obtained with higher volumtric efficiency when same amount of heat is released in the cylinder. 

    Would anybody show me some references about the relationship between volumetric efficiency and combustion temperature?

    Thank you for your help and attention.

    Siva Kumar


    Increasing in volumetric efficiency is essential in case of a naturally aspirated engines where the engines produces very less sp power. other way to increase it to switch to turbocharged.

    The relationship between the combustion temperature and Volumetric eff is proportional.

    Higher the Air flow , can inject the more fuel with better lambda ( >1.4 ) values, where the smoke levels are in control. However the Structural stability of cyl head and block to be taken care of when we moved to higher specific power.

    Hope you got some information.

    Have a nice time.



  • Ali Attia added an answer:
    What is the difference between knocking and detonation in internal combustion engines ?

    what is the difference between knocking and detonation in internal combustion engine, is one of them occurs with the gasoline and the other with the  diesel engines or both of them has the same meaning?

    Ali Attia

    I need to write that the engine knock is a result of opposed pressure waves that may lead to engine damage due to occurrence of abnormal combustion processes among of them is detonation (in addition to the pre-ignition and/or surface ignition). Detonation itself has a definition of high propagating flame, but for ICE it indicates the auto-ignition of hot spots that already possess high turbulent intensity and so the generated reaction proceed very fast. Finally it is right to say that the successive occurrence of detonation can lead to (the formation of hot regions at cylinder wall due to high rate of heat transfer associated with high turbulence and so pre-ignition on these regions is generated)  the engine knock.

  • Roberto Vizcón Toledo added an answer:
    How do catalyst help to reduce fouling on boiler?

    In some papers it is mentioned that catalyst (dolomite, lime, silica, etc.) help to reduce tar fouling on heating surface (boiler wall) in biomass combustion. But don't clearly mention how it works. Please share the science behind the fouling reduction process.

    Roberto Vizcón Toledo

    I will try to translate it for send you a copy then. I´sorry.

  • Giuma Fellah added an answer:
    How do we explain why low temperature combustion engines achieve higher thermal efficiency?
    It seems to violate the Carnot efficiency for heat engines. Low temperature combustion engines have gained significant interest in engine research due to lower average burning temperature, lowering heat loss that contributes to the reduction of thermal efficiency. However, according to the Carnot heat engine thermal efficiency definition, increasing source temperature increases thermal efficiency.
    Giuma Fellah
    In this case we should reduce the amount of heat rejected to surroundings, i.e. we should reduce the ratio of heat rejected to heat supplied to the engine. This can be done be reducing the average temperature of the exhaust gases. However, the exhaust temperature must be always greater than the dew point. We may need larger surface areas to insure the desired rate of the heat transfer for closed systems.
  • Andrew P. Wandel added an answer:
    What's the difference between flame blow off and flame blow out?

    what's difference between flame blow off and flame blow out???? plz help

    Andrew P. Wandel

    Hello Mohamed,

    "Blow off" is when the flow speed is so high, the flame cannot be stabilised (kept at a fixed location), and so you can watch the flame propagate downstream and eventually extinguish.

    I haven't used "blow out" in a technical sense, but colloquially you "blow out a candle".  I would describe this phenomenon as a very high flow speed that quenches the flame, so that it extinguishes at that location.

    For "blow off", there is some flow to sustain the flame and the cause of the blow off is additional (but not excessive) speed in the same direction so that the flame can continue to burn as it moves because there is a combustible mixture.  For "blow out", there is an enormous speed of flow, coming from any direction, which quenches the flame immediately because the temperature is quickly reduced and the mixture becomes excessively lean (normally) or excessively rich, so that there is no longer a combustible mixture.


  • Paul Gateau added an answer:
    Can any one suggest how to couple CSTR , WSTR and PFR for simulation of gas turbine combustion chamber?

    I am planning to simulate gas turbine combustion chamber as a reactor. But reactor modelling is suggesting various theories for different thermodynamic conditions such as constant volume reactor, constant pressure reactor, well stirred reactor and plugged flow reactor. how to couple them to simulate gas turbine combustion chamber?

    Paul Gateau

    To complete Manish Shah's answer.

    It's true that CFD simulation is a good method (may be the more appropriate) but it can be complicate.

    Chemkin is also complicate if you don't have the software. If you have the software Chemkin or another like Comsol you can simulate with the GRIMECH data for gaz combustion.

    The Borghi diagram is interesting to see the theorical situation in combustion for a perfectly stirred reactor.

    There are many papers dealing with combustion and perfectly stirred reactors.

    CFD : the kinetics are rather simple but you can obtain the temperature and velocity repartition in 3D

    Perfectly stirred : you can simulate very complex kinetics.

  • Amitav Chakraborty added an answer:
    Can we blend LPG and diesel fuel inside the cylinder?
    Through intake manifold can we inject LPG and mixing with diesel particle during the compression stroke?
    Amitav Chakraborty

    I agree to Mr Ekenechukwu C Okafor partially if we go for increasing the cetane number of LPG in diesel platform with some additives it may reduce the HC emissions,but on other hand the PM emission will try to shoot up due to rise in temperature in the cylinder

  • Alexandria Marie Noble added an answer:
    Does anyone know which type of ethanol blend is most effective in motorcycles?
    Different percentage mixes of ethanol and petrol used to drive motorcycles, have a significant impact on emissions and fuel consumption.
    Alexandria Marie Noble

    According to the US Department of Energy, E15 is prohibited for use in motorcycles and other small engines.The Renewable Fuels Association (RFA) has recognized concerns
    of the small engine community (ethanol degrades engine parts and hoses and essentially gums up the works). The RFA outlined possibilities to allow for the use of E15 for on-road applications to the EPA, specifically passenger vehicles. According to the EPA there is insufficient evidence to determine whether E15 emissions will cause or contribute to non-road vehicles and non-road engines failing to meet emission standards, but it was suggested that the EPA grant a waiver for E15 limited to passenger vehicles/vehicles with large on road engines.

    Some of these publications below, they may be of use to you, good luck. 

    + 5 more attachments

  • Alliche Mounir added an answer:
    How to model a simple 1D flame propagation in a SI engine?
    I want to model the propagation of a flame front using MATLAB. What model can be used? Any references from where I can get information?
    Alliche Mounir

    I think you can use the book of Turns "An Introduction to Combustion”, McGraw-Hill, 2000, it is Very appropriate for this case and for your Library. You must use a multi scale method for detecting the flame region (corresponging to Tmax), for example the multigrid method.

  • Zol Bahri Razali added an answer:
    How can one get product reaction rate of each species from output files when using the "FlameMaster"?

    The process needs some information such as mass fraction and product reaction rate of each species at a given point. Steady laminar flamelet model and a certain PDF is applied. But in the FlameMaster outputfile(e.g. FlameMaster\FlameManRun\Diff\Steady\H2\OutMixFrac\H2_p01_0chi1.73414tf0300to0300), I cannot find reaction rate of required species, except for Z, T, massfraction- , W, chi, et al.

  • Awajiogak Anthony Ujile added an answer:
    Standard temperature-rise curves for jet fuels, where can I find them?

    Hi everyone, 

    I'm new in the jet fuel world, I would like to have some info about temperature-rise curves of jet fuels (kerosine...) as a function of pressure and air temperature.

    Thank you.

    Awajiogak Anthony Ujile

    Please consider the combustion reaction equation of kerosene (jet fuel). Check the thermodynamics of the process with respect to enthalpy and entropy charts. With these correlations, you should be able to obtain the temperature rise curve of jet fuel. I hope your objective is to evaluate the cost effectiveness of the jet fuel?

  • Mohammed Saber Gad added an answer:
    What are the properties of glass used for combustion diagnostics application and how to measure the properties of the glass?
    Glass used for optical engines
    Mohammed Saber Gad

    i think this glass resists the thermal and mechanical stresses. Quartz glass resists high pressures in internal combustion engines. 

  • Mitja Kožuh added an answer:
    What are the hazards and risks from an offshore LNG production and storage facility?

    I am researching on the harzards and risk from FLNG and how they compare with other more familiar related technologies. Relevant literatures as well as your thoughts would be appreciated.

    Mitja Kožuh
    Regarding explosion there was explosion in production facility in Skikda in Algiers (2004.01.19). The other problems are pool and jet fire and possibly late ignition of the cloud after leaking into the water (reference Sandia documents). Rapid Phase Transition explosion in the tank.
  • Gabriel Negreanu added an answer:
    How are gas turbine cycles affected by oxygen enrichment in the air?
    see above
    Gabriel Negreanu

    Usualy, the air excess coefficient in the combustion chamber of gas turbines is quite high (2,5-4) in comparison with regular furnaces (1,2-1,5 with 6% oxygen in the flue gasses).  It's a lot of oxygen in the flue gasses, so it's possible to make also a post combustion without supplementary air injection. In conclusion, the air enrichment with oxygen should not affect the cycle parameters too much.

  • Joseph F McDonald added an answer:
    How can I measure the higher lambda value above 1.8 from a lambda sensor?
    1.Typical Lambda sensor range is between 0.2 to 1.8. How to measure higher lambda value more than 1.8 in experiments. i.e to measure very lean equivalence ratio? Can Brett schneider equation be used for low temperature combustion when the lambda value is more than 1.8. or brett schneider equation is valid only for lambda value closer to 1?
    2. whether lambda sensor is available for different ranges with digital display and connection to ECU for control?
    3. Fuel to be used diesel and gasoline.
    Joseph F McDonald

    In my experience, UEGO sensors can be calibrated out to the O2 concentration in air if necessary. If you are on a tight budget, you can use OE Bosch or NGK automotive sensors and a either a UEGO controller or DIY kit from:

    We used the Horiba MEXA units (Bosch sensors if memory serves me) and also one-off instrumentation with NGK sensors.  We typically calibrated UEGO sensors using a capillary gas divider and a mixture of 2.6% H2 - 6.6% CO - 10 % CO2 - balance N2 for calibrating rich and then chose an oxygen concentration for lean calibration based on the application.  The rich calibration mixture gave us a rich-span value equivalent to approximately 0.81 lambda.  For lean calibration, 4.7% O2 spanned at about 1.27 lambda (fine for most stoichiometric gasoline applications) and 9.7% O2 spanned at about 1.91 lambda (fine for many lean-burn applications) - just choose the oxygen concentration to span to the lean lambda value that you are looking for. 

  • Михаил Андронов added an answer:
    What is the environmental impact of fuel consumption in air pollution?
    What is the amount of Co produced for one liter of fuel combustion?
    Михаил Андронов

    CO and CO2 - a little dangerous components of pollutions. The least dangerous component, of course, is CO2, if you ignore the thermal pollution.

    The most dangerous components (ascending danger): hydrogen - carbon,

    nitrogen oxides NOx and benzoalfapiren.

    In diesel engines, of course, very dangerous nitrogen oxides NOx and soot (smoke).

  • Tamilalagan Natarajan added an answer:
    Can anyone help with power transformer dataset (DGA test results)?

    I am in urgent need of data from transformer DGA test results. I have some transformer dga test results with only key gases and hydrocarbon gases. 

    I need some DGA results with additional features such as moisture, oil breakdown values , acidity etc. All data will be kept confidential and will be used for research only. Please help.

    Tamilalagan Natarajan

    Hi, I am not sure if I was clear. I am in need of a dataset from transformer DGA for testing. I am planning to use a combination of IEEE/IEC methods for fault diagnosis. If you happen to have any DGA results that contain more features, please share it with me. The more features, the better.

  • Petra Roosen added an answer:
    How much actual (practically) air is required for 1kg/hr coal combustion?

    How much actual (practically) air is required for 1kg/hr coal gasification?

    Petra Roosen

    @Rasool: You are right, but I was trading oxygen against ashes - at least for the 1st order approximation. :-)

  • Arun Kishore Eswara added an answer:
    What is the optimum acidity level of a bio-diesel for IC engine operation?
    Which components of the IC engine are affected?
    Arun Kishore Eswara
    Every engine manufacturer sets his own specification on the type of fuels and lubes that can be used. There are rules framed like in Maritime applications (by IMO) that the fuels should be free of inorganic acids. This is something to do with the health of the crew. Further if you refer some international standards like the EN 14214:2003 standard for bio-diesels, the maximum acidity specified is 0.5 mg KOH/g. While that of crude liquid bio fuels is 15mg KOH/g. The acidity is more important as to the suitability for the engine considering the type of materials used in the fuel systems, combustion and exhaust components and exhaust heat recovery units.
    The conclusion is TAN is mere acceptance to the engine hence quoted as maximum mg KOH/g.
  • Per Tunestal added an answer:
    Why is cycle to cycle fluctuation in HCCI /PCCI engine very high, how can it be controlled?
    This is for gasoline PCCi engine running with gasoline alone without diesel injection at TDC.
    Per Tunestal

    In general, cycle to cycle variations for HCCI/PCCI engines are high when the engine is operated at limit of ignitability. This means that for each speed/load operating point with a given fuel there is a certain acceptable region of combinations of inlet temperature, compression ratio, air/fuel ratio and EGR that provides stable combustion. If you are near the edge of this stability region you can run into either excessive cycle to cycle variation or knock.

  • Mohammad Faisal added an answer:
    What is a good way to validate CFD results (i.e. exhaust velocity, temperature, pressure etc) for Rocket combustion for propulsion system?
    For aerodynamic design (aircraft or aerofoil or any body), we have wind tunnel tests which validate the CFD simulated results for aerodynamic design. Similarly for automotive combustion chamber, we can carry out experimentation of fuel combustion inside the chamber upto certain extent for the cfd simulated results.
    But for the cfd simulation like combustion chamber design or combustion modelling in rocket propulsion system, how the simulated results are validated as experimentation of propulsion is not possible or it gives a huge cost. What is the method of validation and comparison of simulated data as we do in external aerodynamics?
    Mohammad Faisal
    Thanks a lot. It was really helpful.
  • Harjeet Nath added an answer:
    How can I measure the fluoride amount of a gas sample? Which is the best equipment and why?
    How can I measure gaseous Fluoride?
    Harjeet Nath
    Thank You, GC can be used??
  • Aimen Zeiny added an answer:
    Why is Naphtha not used as a fuel for Spark Ignition Engines?
    Can anyone tell me the main reasons that prevent the use of Naphtha as a fuel in SI engines?
    Aimen Zeiny
    Thank you Gautam. But I did a piece of research on using Naphtha in SI engine. I found that adding 7 vol.% of methanol to Naphtha enhances the engine performance and reducing emissions even better than using gasoline as fuel. Also, I measured the noise of the engine and I found that at this percentage the noise is lower than the noise generated when using Gasoline.
    What do you think?
    I would be grateful if I can hear your comment.
  • Marek Flekiewicz added an answer:
    Is there any study on the rate of natural gas loss in natural gas engines through piston rings? To what extend does this affect the performance?
    When gasoline or diesel engines are converted to natural gas, one obvious result is the reduction in power due to volumetric loss and slower flame speed. In addition, the charge heating value is reduced from the sipping out of natural gas through the piston rings during compression stroke. All these lead to power loss.
    Marek Flekiewicz
    I think the best way is to ask M.A.N directly. The report explains among other why the rings and piston have a different design. I do not know any other publications on this subject.

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