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Full-Text Articles in Heat Transfer, Combustion
From Spark To Wildfire: Predicting Wildfire Origins And The Efficacy Of “Fire Safe” Cigarettes In California Grasslands, Trevor Blackwell Haltermann
From Spark To Wildfire: Predicting Wildfire Origins And The Efficacy Of “Fire Safe” Cigarettes In California Grasslands, Trevor Blackwell Haltermann
Cal Poly Humboldt theses and projects
As wildfires in North America increase in size and frequency, the societal impacts become greater as well. With greater risk and high fire suppression costs it is pertinent to improve fire investigation methods and limit the potential for human caused ignitions. Two distinct studies were carried out to assess the accuracy of fire pattern indicators and the efficacy of “fire safe” cigarette technology in lowland grass fuel types in California. The first study utilized 24 experimental small-scale fires within a wind tunnel to examine the accuracy of microscale fire pattern indicators and the factors that influence the accuracy of predictions …
High-Pressure Ignition And Flame Propagation – An Experimental And Numerical Study, James Shaffer
High-Pressure Ignition And Flame Propagation – An Experimental And Numerical Study, James Shaffer
Graduate Theses, Dissertations, and Problem Reports (ETD)
The next generation of advanced combustion devices is being developed to operate under ultra-high-pressure conditions, to improve combustion efficiency and reduce pollutant emissions. However, at such extreme conditions, flame tends to become unstable, and measurement of fundamental properties becomes challenging. The laminar burning speed ( ) is among those properties, as it is required for the validation of kinetic models and the modeling of turbulent combustion. One potential method to resolve this issue and achieve measurement at very high pressures (i.e., 20-50 atm), is focusing on ignition affected region. The flame kernel in this region is more resistant to perturbations …
Statistical Uncertainty Of The Ignition Time, Burning Rate, And Extinction Characteristics Of Engineered Timber Products, Jacob David
Master's Theses
The characterization of flammability parameters such as time to ignition, mass loss rate (MLR), and extinction criteria is critical for understanding ignition and burning behavior of timber products. These parameters, often determined with bench scale experiments, have previously been presented in literature. However, standard test methods generally use relatively low trial quantities (e.g., n=3) which can potentially cause large variation in reported values. This study investigates the influence of trial quantity on observed statistical variation in key flammability metrics for timber products (e.g., ignition time, peak MLR, MLR at extinction). Using a conical heater, 100 repeat trials were conducted …
Direct Numerical Simulation Of Supercritical Co2 Mixing And Combustion, Syed Mohammad Ovais
Direct Numerical Simulation Of Supercritical Co2 Mixing And Combustion, Syed Mohammad Ovais
All Dissertations
The supercritical CO2 power cycle (sCO2 ) is a relatively new technology, which promises to reduce CO2 emissions with potentially higher efficiencies. However due to challenging conditions posed by supercritical pressures, the mixing and ignition phenomena in sCO2 combustion is relatively less understood and studied. The primary objective of the current study is to investigate these fundamental processes using homogeneous ignition calculations (HMI) and direct numerical simulations (DNS). Broadly, the study is divided into two major parts. In the first part supercritical mixing in sCO2 relevant conditions is investigated. To achieve this, DNS of temporally …
The Effect Of Orientation On The Ignition Of Solids, David Morrisset
The Effect Of Orientation On The Ignition Of Solids, David Morrisset
Master's Theses
The ignition of a solid is an inherently complex phenomenon influenced by heat and mass transport mechanisms that are, even to this day, not understood in entirety. In order to use ignition data in meaningful engineering application, significant simplifications have been made to the theory of ignition. The most common way to classify ignition is the use of material specific parameters such as such as ignition temperature (Tig) and the critical heat flux for ignition (CHF). These parameters are determined through standardized testing of solid materials – however, the results of these tests are generally used in applications …
High Injection Pressure Dme Ignition And Combustion Processes: Experiment And Simulation, Xiucheng Zhu
High Injection Pressure Dme Ignition And Combustion Processes: Experiment And Simulation, Xiucheng Zhu
Dissertations, Master's Theses and Master's Reports
With nearly smokeless combustion, Dimethyl Ether (DME) can be pressurized and used as a liquid fuel for compression-ignition (CI) combustion. However, due to its lower heating value and liquid density compared with diesel fuel, DME has a smaller energy content per unit volume. To obtain an equivalent energy content of diesel, approximately 1.86 times more quantity of DME is required. This can be addressed by a larger nozzle size or higher injection pressure. However, the effect of high injection pressure on DME spray combustion characteristics have not yet been well understood. In order to fill this gap, spray and combustion …
Low Temperature Split Injection Spray Combustion: Ignition, Flame Stabilization And Soot Formation Characteristics In Diesel Engine Conditions, Ahmed Abdul Moiz
Low Temperature Split Injection Spray Combustion: Ignition, Flame Stabilization And Soot Formation Characteristics In Diesel Engine Conditions, Ahmed Abdul Moiz
Dissertations, Master's Theses and Master's Reports
The aim of the PhD work is to investigate the fundamental differences in combustion behavior when split injections are used in low temperature combustion regime. In this thesis, the first injection is also called as pilot injection and second injection is also called as main injection. The broad aspects which are studied encompassing the investigation is to study the ignition delay, lift-off and soot formation of such a double split spray combustion. The mechanisms of ignition, lift-off and soot production are to be studied since the main ignition and lift-off were found to differ from the pilot which effect net …
Heat Transfer Characteristics In Wildland Fuelbeds, Justin English
Heat Transfer Characteristics In Wildland Fuelbeds, Justin English
Theses and Dissertations--Mechanical and Aerospace Engineering
The fundamental physics governing wildland fire spread are still largely misunderstood. This thesis was motivated by the need to better understand the role of radiative and convective heat transfer in the ignition and spread of wildland fires. The focus of this work incorporated the use of infrared thermographic imaging techniques to investigate fuel particle response from three different heating sources: convective dominated heating from an air torch, radiative dominated heating from a crib fire, and an advancing flame front in a laboratory wind tunnel test. The series of experiments demonstrated the uniqueness and valuable characteristics of infrared thermography to reveal …