An Investigation of the Formation and Venting of Flammable Mixtures Formed Within Liquid Fuel Vessels

1999 ◽  
Vol 121 (1) ◽  
pp. 68-73 ◽  
Author(s):  
R. Bunama ◽  
G. A. Karim ◽  
C. Y. Zhang
Keyword(s):  
Liquid Fuel ◽  
Cylindrical Vessel ◽  
Fuel Vapor ◽  
Combined Effects ◽  
Mass Energy ◽  
Fire Hazards ◽  
Fuel Surface ◽  
Fuel Tanks ◽  
High Volatility ◽  
Energy And Momentum

The paper describes results of a parametric study obtained while using an analytical model described earlier (Bunama and Karim, 1997b) investigating the combined effects of mass, energy, and momentum transfer with variable transport and thermodynamic properties on the formation of fuel vapor-air mixtures above a stagnant liquid fuel surface within the confines, of a vertical cylindrical vessel. This was done mainly to examine the establishment of the formation of flammable mixtures and their changes in size and location with time within liquid fuel tanks that are partially empty. The effects of changes in the ambient and wall temperatures, presence of liquid on the walls and vessel geometry were considered. Moreover, the results of a corresponding experimental investigation are presented. Much of the data relates to the high volatility fuel n-pentane that represents the lighter fuel fractions in commercial fuels which through their early evaporation contribute much to the fire hazards in fuel tanks.

An Investigation of the Formation and Venting of Flammable Mixtures Formed Within Liquid Fuel Vessels

1998 ◽  
Author(s):  
R. Bunama ◽  
G. A. Karim ◽  
C. Y. Zhang
Keyword(s):  
Liquid Fuel ◽  
Cylindrical Vessel ◽  
Combined Effects ◽  
Mass Energy ◽  
Fire Hazards ◽  
Fuel Surface ◽  
Fuel Tanks ◽  
High Volatility ◽  
Energy And Momentum ◽  
Fuel Vapour

The paper describes results of a parametric study obtained while using an analytical model described earlier (Bunama and Karim, 1997b) investigating the combined effects of mass, energy and momentum transfer with variable transport and thermodynamic properties on the formation of fuel vapour-air mixtures above a stagnant liquid fuel surface within the confines of a vertical cylindrical vessel. This was done mainly to examine the establishment of the formation of flammable mixtures and their changes in size and location with time within liquid fuel tanks that are partially empty. The effects of changes in the ambient and wall temperatures, presence of liquid on the walls and vessel geometry were considered. Moreover, the results of a corresponding experimental investigation are presented. Much of the data relates to the high volatility fuel n-pentane that represents the tighter fuel fractions in commercial fuels which through their early evaporation contribute much to the fire hazards in fuel tanks.

scholarly journals The Total Energy and Momentum Stored in a Particle

2017 ◽  
Vol 9 (2) ◽  
pp. 65
Author(s):  
Eyal Brodet
Keyword(s):  
Total Energy ◽  
Special Relativity ◽  
Decay Time ◽  
Rest Mass ◽  
Minimum Time ◽  
Mass Energy ◽  
Light Velocity ◽  
Extra Energy ◽  
Definition Of ◽  
Energy And Momentum

In this paper we reconsider the conventional expressions given by special relativity to the energy and momentum of a particle. In the current framework, the particle's energy and momentum are computed using the particle's rest mass, M and rest mass time, t_m=h/M c^2  where t_m has the same time unit as conventionally used for the light velocity c. Therefore it is currently assumed that this definition of time describes the total kinetic and mass energy of a particle as given by special relativity. In this paper we will reexamine the above assumption and suggest describing the particle's energy as a function of its own particular decay time and not with respect to its rest mass time unit. Moreover we will argue that this rest mass time unit currently used is in fact the minimum time unit defined for a particle and that the particle may have more energy stored with in it. Experimental ways to search for this extra energy stored in particles such as electrons and photons are presented.

scholarly journals Numerical investigations of stainless steel melt motions on the surface of uranium dioxide

2019 ◽  
Vol 196 ◽  
pp. 00005 ◽  
Author(s):  
Eduard V. Usov ◽  
Pavel D. Lobanov ◽  
Ilya A. Klimonov ◽  
Alexander E. Kutlimetov ◽  
Anton A. Butov ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Uranium Dioxide ◽  
Momentum Conservation ◽  
Mass Energy ◽  
Numerical Investigations ◽  
Fuel Rod ◽  
The Core ◽  
Fuel Pin ◽  
Energy And Momentum ◽  
Coolant Velocity

The paper contains the results of numerical simulation of stainless steel melt motions on the surface of uranium dioxide. The investigations are performed for purposes of understanding of the fuel rod behavior during the core disruptive accident in the fast reactors. The systems of mass, energy and momentum conservation equations are solved to simulate melt motion on the surface of the fuel pin. Heat transfer and friction between melt and pin's surface and melt and coolant flow are taken into consideration. The dependences of mass of the melt and the features of the melt motion on coolant velocity and contact angle between melt and surface of the fuel rod are presented.

Emulsified Fuel for Military Aircraft

1968 ◽  
Author(s):  
J. Nixon ◽  
T. J. Wallace ◽  
Alan Beerbower
Keyword(s):  
Liquid Fuel ◽  
Military Aircraft ◽  
Fire Hazards ◽  
Temperature Range ◽  
Emulsified Fuel ◽  
Flow Through ◽  
Made In

An analysis of statistics of aircraft crashes shows that approximately 70 percent of the fatalities are due to fire. The fire hazards in a crash situation are largely associated with liquid fuel. These problems may be either minimized or eliminated by thickening the fuel. This paper summarizes work carried out under an Army contract (DA 44-177-AMC-387(T)) aimed at the formulation of JP-4 fuel emulsions which reduce the fire hazards associated with liquid JP-4. Two JP-4 emulsions (designated WSX-7063 and WSX-7165) which appear to meet the study contractual requirements possess 99 percent of the fuel value associated with JP-4; they reduce the rate at which combustible vapors are released; they have yield stresses which will retard flow through a tank puncture; they are stable over the temperature range of −20 F to 130 F (WSX-7165 is stable over the range of −65 F to 160 F); and they are compatible with aircraft materials of construction. WSX-7165 is being made in 1000-gal batches and it is under evaluation by various engine manufacturers. The fuel has also been tested in several simulated crash situations and the results were quite favorable.

Assessing Fuel Property Effects on Cavitation and Erosion Propensity Using a Computational Fuel Screening Tool

2019 ◽  
Author(s):  
Gina M. Magnotti ◽  
Sibendu Som
Keyword(s):  
Liquid Fuel ◽  
Screening Tool ◽  
Performance Metrics ◽  
Fuel Injection ◽  
Fuel Properties ◽  
Fuel Vapor ◽  
Strong Negative Correlation ◽  
Initial Development ◽  
Fuel Property ◽  
Pressure Surface

Abstract To advance compression ignition combustion strategies, researchers have evaluated fuel property effects and their impact on achieving higher efficiencies and lower emissions levels relative to current capabilities. Within the Department of Energy’s Co-Optima initiative, there has been a recent focus on understanding the influence of fuel properties on fuel injection performance. To help identify candidate fuels that can meet desired injector performance metrics, a computational fuel screening tool is under development that can link fuel properties with the tendency of a given fuel to cavitate and lead to cavitation-induced erosion. In the initial development of this tool, five liquid fuel properties were selected to represent candidate fuels, namely density, viscosity, vapor pressure, surface tension, and heat of vaporization. A design of experiments methodology was employed to generate a set of pseudo-fuel cases, which can represent the main effects and interactions among the fuel properties and be related to cavitation erosion predictions. Large eddy simulations were performed using a mixture modeling approach to predict the cavitation and erosion propensity of these pseudo-fuels in terms of the mean fuel vapor mole fraction and stored impact energy from repeated cloud collapse events. The low order regression models generated from this study revealed the importance of liquid fuel density on cavitation formation, whereas liquid viscosity was found to have a strong negative correlation with erosion severity. The surrogate models were then used in the fuel screening tool to rank the cavitation and erosion tendency of four candidate single-component fuels: methyl decanoate, iso-octane, ethanol and n-dodecane. While the fuel screening tool was not able to quantitatively predict the cavitation and erosion response metrics, the tool was able to accurately rank the relative cavitation and erosion propensity of the four fuels. Overall, ethanol and iso-octane were observed to produce the highest levels of cavitation and erosion, respectively.

Assessment of Fire Hazards and Mitigation Methods in Locomotive Fuel Tanks

2011 ◽  
Author(s):  
Basant K. Parida ◽  
James Carter ◽  
Abdullatif K. Zaouk ◽  
John Punwani
Keyword(s):  
Diesel Fuel ◽  
Fire Hazard ◽  
Normal Operation ◽  
Vapor Concentration ◽  
Potential Hazard ◽  
Partial Recovery ◽  
Fire Hazards ◽  
Operational Conditions ◽  
Fuel Loss ◽  
Fuel Tanks

Diesel fuel carriage in locomotives, while safe in normal operational conditions, presents a potential hazard in the event of serious accident or derailment. Development of an effective mitigation method against this hazard requires an understanding of operational conditions that lead to fuel spill and fire. This paper describes a study of fire hazard stemming from rail accidents and potential approaches to mitigation. Data for the study was obtained from a large sample of National Transportation Safety Board (NTSB) investigation reports for accidents involving both freight and passenger locomotive accidents over a 10-year period. Approximately 25% of the events reviewed resulted in fuel release. In addition, of the events that resulted in fuel loss, a large majority (almost 70%) resulted in fire. Most cases with major fires led to loss of life and/or property, including destruction of multiple locomotives. Typical road locomotives carry 3,000–4,500 gallons of diesel fuel during normal operation. As the locomotive consumes fuel, large volumes are available for vapor generation within the tank. In a post-collision scenario, the vapor that vents to the atmosphere at temperatures close to flash point of the fuel presents a significant fire hazard. Further, flammable mists can be generated by the sprays that develop due to fuel leaks from the post-impact movement of a train. Previous laboratory tests on a scaled tank demonstrated that fire in a fuel-rich vapor can flash back inside the tank causing an explosion or a large fire. This paper also assesses potential technologies to prevent or mitigate fire hazards in locomotive fuel tanks. These include fuel tank leak prevention or reduction of outflow from breached fuel tanks, monitoring vapor concentration within fuel tanks, and limiting vapor concentrations inside tank to maintain levels below the Lower Explosive Limit (LEL). Potential benefits of the latter method include minimization of pollution from escaping vapor as well as partial recovery of reusable fuel from vapor.

scholarly journals Real-Time Interface Model Investigation for MCFC-MGT HILS Hybrid Power System

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2192 ◽  
Author(s):  
Chen Yang ◽  
Kangjie Deng ◽  
Hangxing He ◽  
Haochuang Wu ◽  
Kai Yao ◽  
...  
Keyword(s):  
Power System ◽  
Real Time ◽  
Molten Carbonate Fuel Cell ◽  
Prototype System ◽  
Interface Model ◽  
Mass Energy ◽  
Molten Carbonate ◽  
Hybrid Power System ◽  
Hybrid Power ◽  
Energy And Momentum

The research on the control strategy and dynamic characteristics of the Molten Carbonate Fuel Cell-Micro Gas Turbine (MCFC-MGT) hybrid power system has received much attention. The use of the Hardware-In-the-Loop Simulation (HILS) method to study the MCFC-MGT hybrid power system, where the MCFC is the model subsystem and the MGT is the physical subsystem, is an effective means to save development cost and time. The difficulty with developing the MCFC-MGT HILS system is the transfer of the mass, energy, and momentum between the physical subsystem and the model subsystem. Hence, a new Simulation–Stimulation (Sim–Stim) interface model of the MCFC-MGT HILS hybrid power system to achieve a consistent mass, energy, and momentum with the prototype system of the MCFC-MGT hybrid power system is proposed. In order to validate the Sim–Stim interface model before application in an actual system, both a real-time model of the MCFC-MGT hybrid power system and the MCFC-MGT HILS hybrid power system based on the Sim–Stim interface model were developed in the Advanced PROcess Simulation (APROS) platform. The step-up and step-down of the current density, which were strict for the Sim–Stim interface model, were studied in these two models. The results demonstrated that the Sim–Stim interface model developed for the MCFC-MGT HILS hybrid power system is rapid and reasonable.

STUDY OF CIRCULATING COAL FLUIDIZED BOILERS

2015 ◽  
Vol 3 (6) ◽  
pp. 396 ◽  
Author(s):  
Sugato Hajra ◽  
Abhishek Aditya Patra
Keyword(s):  
Heat Transfer ◽  
Mathematical Models ◽  
Domain Knowledge ◽  
Regulatory Compliance ◽  
Mass Energy ◽  
Survey Paper ◽  
Design Changes ◽  
Energy And Momentum ◽  
Technological World ◽  
Steam Production

In the days of modernization, industrialization, technological world we find out a new method of steam production with help of coal. This state of act systems are manufactured over a range of 500 TPH.This boilers are highly efficient, multi coal firing capacity, less emission of so2 and nox gases, utilize high ignite cokes, petcoats,washery rejects. This survey paper is intended to comprehensively give an account of domain knowledge related to CFBC boiler. The authors touch upon the design changes which are introduced in the component levels in order to ease the operation, enhance the performance and to meet the regulatory compliance. In addition, salient correlations related to hydrodynamics, heat transfer and combustion are narrated to facilitate the control and system engineers to develop mathematical models using conservation of mass, energy and momentum equations.

Post-Combustion In-Cylinder Vaporization During Cranking and Startup in a Port-Fuel–Injected Spark Ignition Engine

2005 ◽  
Vol 128 (2) ◽  
pp. 397-402 ◽  
Author(s):  
Jim S. Cowart
Keyword(s):  
Combustion Chamber ◽  
Liquid Fuel ◽  
Combustion Process ◽  
Spark Ignition ◽  
Liquid Films ◽  
Spark Ignition Engine ◽  
Fuel Vapor ◽  
Intake Port ◽  
Warm Up ◽  
Flame Ionization

During port-fuel–injected (PFI) spark-ignition (SI) engine startup and warm-up fuel accounting continues to be a challenge. Excess fuel must be injected for a near stoichiometric combustion charge. The “extra” fuel that does not contribute to the combustion process may stay in the intake port or as liquid films on the combustion chamber walls. Some of this combustion chamber wall liquid fuel is transported to the engine’s oil sump and some of this liquid fuel escapes combustion and evolves during the expansion and exhaust strokes. Experiments were performed to investigate and quantify this emerging in-cylinder fuel vapor post-combustion cycle by cycle during engine startup. It is believed that this fuel vapor is evaporating from cylinder surfaces and emerging from cylinder crevices. A fast in-cylinder diagnostic, the fast flame ionization detector, was used to measure this behavior. Substantial post-combustion fuel vapor was measured during engine startup. The amount of post-combustion fuel vapor that develops relative to the in-cylinder precombustion fuel charge is on the order of one for cold starting (0 °C) and decreases to ∼13 for hot starting engine cycles. Fuel accounting suggests that the intake port puddle forms quickly, over the first few engine cranking cycles. Analysis suggests that sufficient charge temperature and crevice oxygen exists to at least partially oxidize the majority of this post-combustion fuel vapor such that engine out hydrocarbons are not excessive.

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