Effect of Stabilized Water-Diesel Emulsions on External Combustion Characteristics

2013 ◽  
Author(s):  
Mohammad O. Hamdan ◽  
Mohamed Y. E. Selim ◽  
S.-A. B. Al Omari ◽  
Emad Elnajjar ◽  
Mamdouh Ghannam
Keyword(s):  
Heat Release ◽  
Water Content ◽  
Flame Temperature ◽  
Combustion Efficiency ◽  
Strong Impact ◽  
Optimum Water Content ◽  
Small Furnace ◽  
Fuel Nozzle ◽  
The One ◽  
External Combustion

This study presents an experimental investigation of emulsified fuels with water content of 10%, 20% and 30% by volume, using a small furnace under steady combustion conditions. Pure diesel is used as a baseline in the conducted external combustion for comparison purposes. The study found that water content in the emulsion has strong impact on the flame temperature, the flame heat release and the combustion efficiency. The 20% water-diesel emulsion showed a lower flame temperature and higher combustion efficiency. Using the proper water-diesel emulsion, 20%, the heat release rate of the emulsified fuels is comparable to the one obtained in the pure diesel case. The highest flame temperature and heat flux transfer to water jacket is achieved at pure diesel (0% water content). The optimum water content in diesel emulsion strongly depends on the liquid fuel nozzle design.

scholarly journals Effects of Jet Flow Pulsation on Diffusion Flame Performance

2020 ◽  
Vol 9 (4) ◽  
pp. 444-451
Keyword(s):  
Heat Transfer ◽  
Heat Release ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Turbulent Flame ◽  
Flame Temperature ◽  
Combustion Efficiency ◽  
Heat Fluxes ◽  
Pulsating Flow ◽  
Flow Pulsation

The objective of the current research is the experimental investigation of the pulsating flow effects on the combustion performance in terms of the flame temperature distribution, the heat transfer rate, the combustion efficiency and the exhaust gas analysis. The flow pulsation provided through a rotary ball valve in accordance with a variable speed motor arrangement increased the flame temperature fluctuation and the magnitude of heat release. The flow pulsation provides a highly turbulent flame wherein the vortices are enlarged. Increasing Strouhal number [St] of the LPG fuel and air flow increases the time-averaged flame temperature of the pulsating flame up to a saturation level that is dictated by the heat transfer rate enhancement. The maximum average flame temperature is 1263oC at St= 0.041, r= 0 mm and 100 mm from the burner inlet. In addition, increasing the pulsating flow amplitude increases the convection and radiation heat fluxes from the pulsating flame. While increasing the pulsation decreases the exhaust UHC due to increasing the turbulent kinetic energy across the pulsating flame, the exhaust NOx slightly increases due to increasing the heat release rate and the flame temperatures. Pulsation thus enhances the combustion efficiency inside the industrial combustors

The Effect of Elevated Water Content on Ethanol Combustion: A Feasibility Study

2011 ◽  
Author(s):  
Baine B. Breaux ◽  
Sumanta Acharya
Keyword(s):  
Water Content ◽  
Fuel Injection ◽  
Flame Temperature ◽  
Nox Formation ◽  
Financial Return ◽  
Optimum Water Content ◽  
Ethanol Combustion ◽  
Elevated Water ◽  
Hydrous Ethanol ◽  
Optimum Water

In order to make ethanol economically competitive, market forces are demanding that the fuel deliver more energy per dollar invested. The process of distillation accounts for as much as 37% of the energy cost associated with producing bio-ethanol. This paper investigates the possibility of sustaining a combustion reaction with fuel that has a higher water content than is currently accepted as standard. The use of such aqueous fuel in lieu of the more energy expensive alternative could reduce the overhead of producing the fuel and lead to a better financial return. In this study, hydrous ethanol is burned in a continuous flame using a swirl-stabilized combustor with a dump diffuser at the inlet and pressure-orifice atomizing nozzles for fuel injection. The flame is observed as air flow rate is held constant and water content varies from 0% to 40% water. Fundamental relationships between water content and flame temperature, NOx formation, and lean blow out conditions are presented. By characterizing these relationships effectively it may be possible to establish an optimum water content that yields the highest energy delivered per dollar invested.

scholarly journals Combustion Thermodynamics of Ethanol, n-Heptane, and n-Butanol in a Rapid Compression Machine with a Dual Direct Injection (DDI) Supply System

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2729
Author(s):  
Ireneusz Pielecha ◽  
Sławomir Wierzbicki ◽  
Maciej Sidorowicz ◽  
Dariusz Pietras
Keyword(s):  
Heat Release ◽  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Direct Injection ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Injection System ◽  
Rapid Compression Machine ◽  
Process Indicators ◽  
Rapid Compression

The development of internal combustion engines involves various new solutions, one of which is the use of dual-fuel systems. The diversity of technological solutions being developed determines the efficiency of such systems, as well as the possibility of reducing the emission of carbon dioxide and exhaust components into the atmosphere. An innovative double direct injection system was used as a method for forming a mixture in the combustion chamber. The tests were carried out with the use of gasoline, ethanol, n-heptane, and n-butanol during combustion in a model test engine—the rapid compression machine (RCM). The analyzed combustion process indicators included the cylinder pressure, pressure increase rate, heat release rate, and heat release value. Optical tests of the combustion process made it possible to analyze the flame development in the observed area of the combustion chamber. The conducted research and analyses resulted in the observation that it is possible to control the excess air ratio in the direct vicinity of the spark plug just before ignition. Such possibilities occur as a result of the properties of the injected fuels, which include different amounts of air required for their stoichiometric combustion. The studies of the combustion process have shown that the combustible mixtures consisting of gasoline with another fuel are characterized by greater combustion efficiency than the mixtures composed of only a single fuel type, and that the influence of the type of fuel used is significant for the combustion process and its indicator values.

A Spray-Droplet Model for Diesel Combustion

1969 ◽  
Vol 184 (10) ◽  
pp. 28-35 ◽  
Author(s):  
J. Shipinski ◽  
P. S. Myers ◽  
O. A. Uyehara
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Heat Release ◽  
Engine Speed ◽  
Chamber Pressure ◽  
Gas Temperature ◽  
Single Droplet ◽  
Burning Rates ◽  
Burning Model ◽  
The One

A spray-burning model (based on single-droplet theory) for heat release in a diesel engine is presented. Comparison of computations using this model and experimental data from an operating diesel engine indicate that heat release rates are not adequately represented by single-droplet burning rates. A new concept is proposed, i.e. a burning coefficient for a fuel spray. Comparisons between computations and experimental data indicate that the numerical value of this coefficient is nearly independent of engine speed and combustion-chamber pressure. However, the instantaneous value of the spray burning coefficient is approximately proportional to the instantaneous mass-averaged cylinder gas temperature to the one-third power.

Numerical simulation of coupled liquid water, stress and heat for frozen soil in the thawing process

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wei Xiao ◽  
Enlong Liu ◽  
Xiao Yin ◽  
Guike Zhang ◽  
Chong Zhang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Water Content ◽  
Coupled Model ◽  
Frozen Soil ◽  
Water Migration ◽  
Overburden Pressure ◽  
Content Type ◽  
Thawing Process ◽  
Sample Water ◽  
The One

PurposeThe purpose of this paper is to perform the thermo-hydro-mechanical (THM) numerical analysis in order to study the thawing process for frozen soil and to predict the thawing settlement.Design/methodology/approachA new one-dimensional multi-field physical coupled model was proposed here to describe the thawing process of saturated frozen soil, whereby the void ratio varied linearly with effective stress (Eq. 10) and hydraulic conductivity (Eq. 27b). The thawing process was simulated with different initial and boundary conditions in an open system with temperature variations. The mechanical behavior and water migration of the representative cases were also investigated.FindingsThe comparisons of representative cases with experimental data demonstrated that the model predicts thawing settlement well. It was found that the larger temperature gradient, higher overburden pressure and higher water content could lead to larger thawing settlement. The temperature was observed that to distribute height linearly in both frozen zone and unfrozen zone of the sample. Water migration forced to a decrease in the water content of the unfrozen zone and an increase in water content at the thawing front.Research limitations/implicationsIn this study, only the one-directional thawing processes along the frozen soil samples were investigated numerically and compared with test results, which can be extended to two-dimensional analysis of thawing process in frozen soil.Originality/valueThis study helps to understand the thawing process of frozen soil by coupled thermo-hydro-mechanical numerical simulation.

Importance of water content and motion in the one-dimensional conductorK2Pt(CN)4Cl0.3·nH2O

1974 ◽  
Vol 10 (5) ◽  
pp. 1778-1783 ◽  
Author(s):  
M. A. Butler ◽  
H. J. Guggenheim
Keyword(s):  
Water Content ◽  
One Dimensional ◽  
The One

scholarly journals Fuel Effects on the TF30 Engine (Alternate Test Procedure)

1984 ◽  
Author(s):  
P. A. Karpovich ◽  
A. I. Masters
Keyword(s):  
Test Procedure ◽  
Engine Performance ◽  
Combustion Efficiency ◽  
Fuel Properties ◽  
Secondary Importance ◽  
Turbine Engine ◽  
Main Burner ◽  
Alternate Test ◽  
Fuel Nozzle ◽  
Fuel Effects

The objective of the Alternate Test Procedure (ATP) is to develop the capability to qualify new fuels for Navy aircraft use with a minimum of testing. The effect of fuel composition and properties on engine performance and component life has been shown to vary significantly from one engine configuration to another. The P&WA approach to the ATP has been to define fuel effects on the TF30 engine and then apply the methodology to other engines of interest to the Navy. Investigations of the TF30 conducted under the ATP Program and other Navy and Air Force Contracts have produced one of the most complete fuel effect characterizations available for any gas turbine engine. Major fuel effects which have been quantified are the relationships of lubricity to main fuel control reliability, viscosity and volatility to main burner and augmentor ignition limits, and hydrogen content to smoke and combustor life. The effects of fuel properties and composition on combustion efficiency and elastomeric seal life were found to be of secondary importance. Remaining uncertainties are the effects of fuel properties on turbine life and fuel nozzle fouling rate.

scholarly journals Metals and Alloys Additives as Enhancer for Rocket Propulsion: A Review

2021 ◽  
Vol 90 (1) ◽  
pp. 1-9
Author(s):  
Izham Izzat Ismail ◽  
Norhuda Hidayah Nordin ◽  
Muhammad Hanafi Azami ◽  
Nur Azam Abdullah
Keyword(s):  
Specific Impulse ◽  
Flame Temperature ◽  
High Energy ◽  
Combustion Efficiency ◽  
High Energy Density ◽  
Regression Rate ◽  
High Entropy ◽  
Rocket Propulsion ◽  
Wide Range ◽  
Metal Additives

A rocket's engine usually uses fuel and oxygen as propellants to increase the rocket's projection during launch. Nowadays, metallic ingredients are commonly used in the rocket’s operation to increase its performance. Metallic ingredients have a high energy density, flame temperature, and regression rate that are important factors in the propulsion process. There is a wide range of additives have been reported so far as catalysts for rocket propulsion. The studies show that the presence of metal additives improves the regression rate, specific impulse and combustion efficiency. Herein, the common energetic additives for rocket propulsion such as metal and light metals are reviewed. Besides the effect of these energetic particles on the regression behaviors of base (hybrid) fuel has been exclusively discussed. This paper also proposed a new alloy namely high entropy alloys (HEAs) as a new energetic additive that can potentially increase the performance of the rocket propellant system.

Fuel Effects on the TF30 Engine (Alternate Test Procedure)

1985 ◽  
Vol 107 (3) ◽  
pp. 769-774
Author(s):  
P. A. Karpovich ◽  
A. I. Masters
Keyword(s):  
Test Procedure ◽  
Engine Performance ◽  
Combustion Efficiency ◽  
Fuel Properties ◽  
Secondary Importance ◽  
Turbine Engine ◽  
Main Burner ◽  
Alternate Test ◽  
Fuel Nozzle ◽  
Fuel Effects

The objective of the Alternate Test Procedure (ATP) is to develop the capability to qualify new fuels for Navy aircraft use with a minimum of testing. The effect of fuel composition and properties on engine performance and component life has been show to vary significantly from one engine configuration to another. The P&WA approach to the ATP has been to define fuel effects on the TF30 engine and then apply the methodology to other engines of interest to the Navy. Investigations of the TF30 conducted under the ATP Program and other Navy and Air Force Contracts have produced one of the most complete fuel effect characterizations available for any gas turbine engine. Major fuel effects which have been quantified are the relationships of lubricity to main fuel control reliability, viscosity and volatility to main burner and augmentor ignition limits, and hydrogen content to smoke and combustor life. The effects of fuel properties and composition on combustion efficiency and elastomeric seal life were found to be of secondary importance. Remaining uncertainties are the effects of fuel properties on turbine life and fuel nozzle fouling rate.

(Post-)colonial Myths in German History Textbooks, 1989–2015

2021 ◽  
Vol 39 (1) ◽  
pp. 79-99
Author(s):  
Florian Helfer
Keyword(s):  
World War I ◽  
Public Debate ◽  
History Textbooks ◽  
German History ◽  
Strong Impact ◽  
Post Colonial ◽  
The Public ◽  
Textbook Series ◽  
Curricular Framework ◽  
The One

This article examines the evolution of textbook representations of colonialism in two North Rhine-Westphalian textbook series for the Sekundarstufe II since 1989. On the one hand, the article shows that the developing post-colonial discourse in the German public debate had a particularly strong impact on schoolbooks in the mid-2000s. Textbooks reacted quickly to changes in the public debate and have increasingly attempted to deconstruct colonial narratives. However, implicit mental conceptions of African “backwardness” continue to exert some influence even on today’s textbook generation. On the other hand, the article identifies the distortions that appear when colonialism as a global phenomenon is discussed within a curricular framework that focuses on national and European history. Because of the close curricular link between High Imperialism and World War I, textbooks strongly focus on the global rivalry of the European powers, whereas other aspects of colonialism come up short.

Sign in / Sign up

Export Citation Format

Share Document