scholarly journals The dissociation of carbon dioxide at high temperatures

1927 ◽  
Vol 115 (771) ◽  
pp. 318-333 ◽  
Keyword(s):  
Carbon Dioxide ◽  
High Temperatures ◽  
Combustion Engine ◽  
Initial Pressure ◽  
Simple Relation ◽  
Maximum Temperature ◽  
Maximum Pressure ◽  
Complete Combustion ◽  
Explosion Pressure ◽  
Rich Mixture

The power of an internal combustion engine is greatest when operating with a “rich” mixture, that is to say, with a mixture which contains more fuel than is necessary for complete combustion. Similarly, it is found that if mixtures of carbon monoxide and air in varying proportions are exploded in a closed bomb at constant initial temperature and pressure, the explosion pressure is greatest when the ratio CO/O 2 is greater than 2. These phenomena are known to be connected with the dissociation of carbon dioxide at high temperatures, for if there were no dissociation we should expect the explosion pressure to be greatest when CO/O 2 = 2. No attention appears, however, to have been paid to the position of the maximum. It can be shown in the following way that there is a very simple relation between the composition of the mixture giving maximum pressure on explosion, and the dissociation of carbon dioxide at the maximum explosion temperature. Let the initial composition be represented by the expression 2 (1 + a ) CO + O 2 + b N 2 (Total mols = 3 + 2 a + b ), and let P i , T i represent the initial pressure and temperature; P e the maximum pressure observed after explosion, and T e the corresponding maximum temperature.

scholarly journals Gaseous combustion at high pressures. Part III.-The energy absorbing function and activation of nitrogen in the combustion of carbon monoxide

1923 ◽  
Vol 103 (721) ◽  
pp. 205-232
Keyword(s):  
Carbon Monoxide ◽  
High Pressures ◽  
Initial Pressure ◽  
Heat Energy ◽  
Maximum Temperature ◽  
Maximum Pressure ◽  
Complete Combustion ◽  
Large Influence ◽  
Energy Absorbing ◽  
Carbon Monoxide Combustion

In the previous paper of the series* on the explosion of isothermic hydrogen-air and carbon monoxide-air mixtures in the theoretical proportions for complete combustion, at an initial pressure of 50 atmosphere it was shown- (1) that whereas in the case of hydrogen-air mixtures, the maximum pressure was always attained in about 0·005 second after the commencement of combustion, and the cooling set in almost immediately thereafter, in the case of the corresponding carbon monoxide-air mixtures, the time similarly taken for the attainment of maximum pressure was about forty times longer (namely, between 0·18 and 0·24 second), and cooling was delayed for quite an appreciable interval, showing that heat energy was still being liberated long after the maximum temperature had been reached; and (2) that the replacement, even in very small properties, of carbon monoxide bu its equivalent of hydrogen in the mixture 2CO+O 2 +4N 2 had an altogether disproportionately large influence in accelerating the rise of pressure on explosion; indeed, it seemed as though the hydrogen had imposed its own character upon the whole course of the Carbon monoxide combustion, even to the extract of suppressing the aforesaid marked evolution of heat after the attainment of maximum pressure.

scholarly journals Gaseous combustion at high pressures.—Part XIII. The molecular heats of nitrogen, steam, and carbon dioxide at high temperatures

1929 ◽  
Vol 125 (796) ◽  
pp. 119-134 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Energy Distribution ◽  
Quantitative Estimate ◽  
High Pressures ◽  
Maximum Temperature ◽  
Maximum Pressure ◽  
Closed Vessel ◽  
Explosion Products ◽  
The Mean ◽  
The Moment

The only information available concerning the internal energy of gases at temperatures higher than 2000° C. or so is that provided by the results of explosion experiments in which the energy liberated during the combustion serves to raise the products and any other gases that may be present in the medium to some definite maximum temperature. By varying the proportions of the reacting gases, or by adding suitable quantities of some diluent gas, this temperature may be varied between comparatively wide limits. In a previous paper of this series the method of calculating the mean maximum temperature attained during a gaseous explosion in a closed vessel was discussed, and those calculated from our experiments for theoretical CO-air and H 2 -air explosions at initial pressures of between 3 atmospheres and 175 atmospheres were given. At Prof. Bone's request I have recently reviewed and analysed the mass of data accumulated during these researches, together with others resulting from the supplementary experiments described herein, with a view to seeing how far it is possible to deduce, not only a quantitative estimate of the energy distribution at the moment of maximum pressure in typical explosions at high pressures, but also the mean heat capacities of the various explosion products over a temperature range from 15° C. up to various definite points between 2600° and 3000° C. The results of this investigation are described in the present paper.

scholarly journals Temperature effect on explosion parameters of hydrogen-air deflagrations in presence of water vapor

2016 ◽  
Vol 7 (3) ◽  
pp. 39-44
Author(s):  
Marcin Grabarczyk ◽  
Mateusz Żbikowski ◽  
Łukasz Mężyk ◽  
Andrzej Teodorczyk
Keyword(s):  
Water Vapor ◽  
Initial Temperature ◽  
Volume Fraction ◽  
Initial Conditions ◽  
Initial Pressure ◽  
High Water ◽  
Maximum Pressure ◽  
Explosion Pressure ◽  
Maximum Explosion Pressure ◽  
And Shifts

Results of investigation of hydrogen-air deflagrations phenomenon in closed vessel in various initial temperatures and volume fraction of water vapor are presented in following paper. Tests were performed in apparatus which construction complies with EN 15967 recommendations—20-litre sphere. Studied parameters were explosion pressure (Pex) and maximum explosion pressure (Pmax). Defining the influence of the initial conditions (temperature and amount of water vapor) on the maximum pressure of the hydrogen-air deflagration in a constant volume was the main aim. Initial temperatures were equal to 373K, 398K and 413K. Initial pressure was ambient (0.1 MPa). Hydrogen volume fraction differed from 15% to 80%, while humidity volume fraction from 0% to 20%. Ignition source was placed in geometrical center of testing chamber and provided energy between 10-20J from burnout of fuse wire with accordance to abovementioned standard. Common features of all experimentally obtained results were discussed. Maximum explosion pressure (Pmax) decreases with increasing the initial temperature. Furthermore, addition of the water vapor for constant initial temperature decreases value of Pmax and shifts the maximum peak to the direction of lean mixtures. Data provided in paper can be useful in assessment of explosion risk of industry installations working with hydrogen-air atmospheres with high water vapor addition.

Effect of Chemical Hythane Composition on Pressure in Combustion Chamber of Engine

2019 ◽  
pp. 36-42
Author(s):  
A. P. Shaikin ◽  
I. R. Galiev
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Power Plants ◽  
Engine Speed ◽  
Combustion Engine ◽  
Fuel Mixture ◽  
Maximum Pressure ◽  
Chamber Volume ◽  
Excess Air ◽  
Scientific Papers

The article analyzes the influence of chemical composition of hythane (a mixture of natural gas with hydrogen) on pressure in an engine combustion chamber. A review of the literature has showed the relevance of using hythane in transport energy industry, and also revealed a number of scientific papers devoted to studying the effect of hythane on environmental and traction-dynamic characteristics of the engine. We have studied a single-cylinder spark-ignited internal combustion engine. In the experiments, the varying factors are: engine speed (600 and 900 min-1), excess air ratio and hydrogen concentration in natural gas which are 29, 47 and 58% (volume).The article shows that at idling engine speed maximum pressure in combustion chamber depends on excess air ratio and proportion hydrogen in the air-fuel mixture – the poorer air-fuel mixture and greater addition of hydrogen is, the more intense pressure increases. The positive effect of hydrogen on pressure is explained by the fact that addition of hydrogen contributes to increase in heat of combustion fuel and rate propagation of the flame. As a result, during combustion, more heat is released, and the fuel itself burns in a smaller volume. Thus, the addition of hydrogen can ensure stable combustion of a lean air-fuel mixture without loss of engine power. Moreover, the article shows that, despite the change in engine speed, addition of hydrogen, excess air ratio, type of fuel (natural gas and gasoline), there is a power-law dependence of the maximum pressure in engine cylinder on combustion chamber volume. Processing and analysis of the results of the foreign and domestic researchers have showed that patterns we discovered are applicable to engines of different designs, operating at different speeds and using different hydrocarbon fuels. The results research presented allow us to reduce the time and material costs when creating new power plants using hythane and meeting modern requirements for power, economy and toxicity.

Effects of Natural Gas Compositions on Engine In-Cylinder Process

2015 ◽  
Vol 1092-1093 ◽  
pp. 498-503
Author(s):  
La Xiang ◽  
Yu Ding
Keyword(s):  
Natural Gas ◽  
Alternative Fuels ◽  
Combustion Process ◽  
Engine Performance ◽  
Maximum Temperature ◽  
Maximum Pressure ◽  
Test Bed ◽  
Promising Alternative ◽  
Natural Gas Engines ◽  
Lower Maximum

Natural gas (NG) is one of the most promising alternative fuels of diesel and petrol because of its economics and environmental protection. Generally the NG engine share the similar structure profile with diesel or petrol engine but the combustion characteristics of NG is varied from the fuels, so the investigation of NG engine combustion process receive more attentions from the researchers. In this paper, a zero-dimensional model on the basis of Vibe function is built in the MATLAB/SIMULINK environment. The model provides the prediction of combustion process in natural gas engines, which has been verified by the experimental data in the NG test bed. Furthermore, the influence of NG composition on engine performance is investigated, in which the in-cylinder maximum pressure and temperature and mean indicated pressure are compared using different type NG. It is shown in the results that NG with higher composition of methane results in lower maximum temperature and mean indicated pressure as well as higher maximum pressure.

scholarly journals Gaseous combustion at high pressures. —Part X. The co-volume corrections, maximum temperatures and dissociation of steam and carbon dioxide in explosions

1928 ◽  
Vol 119 (782) ◽  
pp. 464-480
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Internal Energy ◽  
High Temperatures ◽  
High Pressures ◽  
Internal Combustion ◽  
Systematic Survey ◽  
Explosion Method ◽  
Maximum Temperatures ◽  
Very High

During the researches upon high-pressure explosions of carbonic oxide-air, hydrogen-air, etc., mixtures, which have been described in the previous papers of this series, a mass of data has been accumulated relating to the influence of density and temperature upon the internal energy of gases and the dissociation of steam and carbon dioxide. Some time ago, at Prof. Bone’s request, the author undertook a systematic survey of the data in question, and the present paper summarises some of the principal results thereof, which it is hoped will throw light upon problems interesting alike to chemists, physicists and internal-combustion engineers. The explosion method affords the only means known at present of determining the internal energies of gases at very high temperatures, and it has been used for this purpose for upwards of 50 years. Although by no means without difficulties, arising from uncertainties of some of the assumptions upon which it is based, yet, for want of a better, its results have been generally accepted as being at least provisionally valuable. Amongst the more recent investigations which have attracted attention in this connection should be mentioned those of Pier, Bjerrum, Siegel and Fenning, all of whom worked at low or medium pressures.

Active site separation of photocatalytic steam reforming of methane using Gas‐Phase Photoelectrochemical system

2021 ◽  
Author(s):  
Tomoki Kujirai ◽  
Akira Yamaguchi ◽  
Takeshi Fujita ◽  
Hideki Abe ◽  
Masahiro Miyauchi
Keyword(s):  
Carbon Dioxide ◽  
Gas Phase ◽  
High Temperatures ◽  
Steam Reforming ◽  
Active Site ◽  
Side Reaction ◽  
System P ◽  
Steam Reforming Of Methane

Steam reforming of methane (SRM) requires high temperatures to be promoted, and the production of carbon dioxide from the side reaction has also become a problem. In this study, we...

Thermal Hydraulic Analysis of Severe Accident in PFBR

2010 ◽  
Author(s):  
K. Velusamy ◽  
P. Chellapandi ◽  
G. R. Raviprasan ◽  
P. Selvaraj ◽  
S. C. Chetal
Keyword(s):  
Atmospheric Pressure ◽  
Fluid Dynamic ◽  
Hydraulic Modeling ◽  
Severe Accident ◽  
Maximum Temperature ◽  
Maximum Pressure ◽  
Dynamic Calculation ◽  
Thermal Hydraulic Modeling ◽  
Thermal Hydraulic Analysis ◽  
Design Pressure

During a core disruptive accident (CDA), the amount of primary sodium that can be released to Reactor Containment Building (RCB) in Prototype Fast Breeder Reactor (PFBR) is estimated to be 350 kg/s, by a transient fluid dynamic calculation. The pressure and temperature evolutions inside RCB, due to consequent sodium fire have been estimated by a constant burning rate model, accounting for heat absorption by RCB wall, assuming RCB isolation based on area gamma monitors. The maximum pressure developed is 7000 Pa. In case RCB isolation is delayed, then the final pressure inside RCB reduces below atmospheric pressure due to cooling of RCB air. The negative pressure that can be developed is estimated by dynamic thermal hydraulic modeling of RCB air / wall to be −3500 Pa. These investigations were useful to arrive at the RCB design pressure. Following CDA, RCB is isolated for 40 days. During this period, the heat added to RCB is dissipated to atmosphere only by natural convection. Considering all the possible routes of heat addition to RCB, evolution of RCB wall temperature has been predicted using HEATING5 code. It is established that the maximum temperature in RCB wall is less than the permissible value.

A Compact External Combustion Engine With High Part-Load Efficiency

2010 ◽  
Author(s):  
Robert Bourque
Keyword(s):  
Combustion Engine ◽  
Front Wheel ◽  
Good Efficiency ◽  
Complete Combustion ◽  
Part Load ◽  
Gasoline Engines ◽  
Full Power ◽  
And Performance ◽  
External Combustion ◽  
External Combustion Engine

An external combustion engine design using steam is described which has good efficiency at full power and even better efficiency at the low power settings common for passenger vehicles. The engine is compact with low weight per unit power. All of its components fit in the engine compartment of a front-wheel drive vehicle despite the space occupied by the transaxle. It readily fits in a rear-drive vehicle. Calculated net efficiencies, after accounting for all losses, range, depending on engine size, from 28–32% at full power increasing to 33–36% at normal road power settings. A two-stage burner, 100% excess air, and combustion temperature below 1500°C assure complete combustion of the fuel and negligible NOx. The engine can burn a variety of fuels and fuel mixes, which should encourage the development of new fuels. Extensive software has been written that calculates full power and part-load energy balances, structural analysis and heat transfer, and performance in specified vehicles including using SAE driving cycles. Engines have been sized from 30 to 3200 hp. In general, fuel consumption should be at least 1.5 times lower than gasoline engines and about the same as diesels operating at low to moderate load settings. Due to this analysis, a prototype, when built, should perform as expected.

scholarly journals Numerical Analysis of Diesel Engine with Modified Inlet Valve

2019 ◽  
Vol 8 (6) ◽  
pp. 2378-2380
Keyword(s):  
Numerical Analysis ◽  
Combustion Engine ◽  
Air Flow ◽  
Valve Lift ◽  
Intake Manifold ◽  
Compression Ignition Engine ◽  
Inlet Valve ◽  
Complete Combustion ◽  
Single Cylinder ◽  
Flow Motion

The Internal combustion engine is one of the widely used mechanical system. The primary aspect of all types of engines is the amount of power produced which, is affected by the complete combustion of a mixture of air and fuel. The objective of this present work is to outline the improved performance of single-cylinder Compression Ignition engine with the aid of geometrical modifications of Inlet manifold. The Study is performed on Kirlosakr CI engine. For modeling of engine assembly, CATIA V5 Software has been used. The Numerical simulations are performed with Ansys 14.5 and solver used as CFX. In this work, two different engine models such as Conventional valve and Modified valve with plate is being considered for CFD analysis. The simulation study of air flow motion with a valve lift of 4 mm, 6 mm and 8 mm is performed for both valve configurations. This numerical analysis aims to maximize the air velocity in the inlet valve with minimum turbulence which in turn improves the engine performance. The study is performed on the single cylinder four-stroke variable compression ratio diesel engines. In the present study, the air flow motion inside the intake manifold of an engine is simulated and investigations are performed by considering the six conditions of the intake valve. The results obtained acts as a basis for further investigation of a variety of valve geometry.

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