Fuel Vapor Generation in LMFBR Core Disruptive Accidents

1975 ◽  
Vol 26 (2) ◽  
pp. 165-171 ◽  
Author(s):  
A. B. Reynolds ◽  
C. A. Erdman ◽  
M. Kirbiyik
Keyword(s):  
Trudy NAMI ◽  
2021 ◽  
pp. 74-86
Author(s):  
G. G. Ter-Mkrtich'yan

Introduction (problem statement and relevance). Hydrocarbon emissions from vaporizationtank fuel contribute significantly to the total emissions of hazardous substances from vehicles equipped with spark ignition engines. To meet the established standards for limiting hydrocarbon emissions caused by evaporation, all modern vehicles use fuel vapor recovery systems, the optimal parameters of which require the availability and application of mathematical models and methods for their determination.The purpose of the research was to develop a model of vapor generation processes in the car fuel tank and a methodology for determining the main quantitative parameters of the vapor-air mixture.Methodology and research methods. The analysis of the processes of vapor generation in the fuel tank was carried out. It was shown that the mass of hydrocarbons generated in the steam space was directly proportional to its volume and did not depend on the amount of fuel in the tank.Scientific novelty and results. New analytical dependences of the vaporization amount on the saturated vapor pressure, barometric pressure, initial fuel temperature and fuel heating during parking have been obtained.Practical significance. A formula was obtained to estimate the temperature of gasoline boiling starting in the tank, depending on the altitude above sea level and the volatility of gasoline, determined by the pressure of saturated vapors. Using the new equations, the vaporization analysis in real situations (parking, idling, refueling, explosive concentration of vapors) was carried out.


Author(s):  
Donna J. Michalek ◽  
Krista L. Stalsberg-Zarling ◽  
Lawrence W. Evers

Recently, additional scrutiny is being placed on all vapor releases to the environment from the fuel system of an automobile. In an effort to lower the overall release of fuel vapor, a preliminary study of the vapor formation processes that occur in a low pressure supply fuel rail was undertaken. The first objective of this work was to determine the means by which fuel vapor is generated within the fuel rail, particularly during hot soak conditions. Then, using this information, the next task was to develop a computational fluid dynamics (CFD) code which would model the vapor formation in the rail. An investigation of the fuel rail material and design revealed that the probable mechanism for vapor formation is nucleate boiling from cavities in the fuel rail surface and at the o-ring connections with the fuel injectors. Therefore, an experiment was constructed to investigate the vapor formation from artificial cavities on a metallic surface and at an o-ring interface. The data collected from the experiment included the departure diameter of the vapor bubbles, the bubble frequency, and the bubble rise velocity. These values, which are used to determine the vapor generation rate, were compared to the results predicted by various correlations available in the literature. Subsequently, a CFD model was constructed of the fuel rail, using Star-CD, by incorporating the appropriate vapor generation correlations as user-defined subroutines. The experimental observations clearly demonstrated that a large amount of vapor was generated at the o-ring interface and, to a lesser degree, from the cavities in the metallic surface. A CFD model was constructed to predict the vapor generated in a fuel rail from these cavities. Existing correlations that describe nucleate boiling adequately model this generation mechanism in the fuel rail. This CFD code can be used to determine the amount of vapor formed under various hot soak conditions. An analytical means of predicting the vapor formation at the o-ring interface will have to be developed in order to complete the CFD model.


2020 ◽  
Vol 4 ◽  
pp. 239784732097975
Author(s):  
Stéphanie Boué ◽  
Didier Goedertier ◽  
Julia Hoeng ◽  
Anita Iskandar ◽  
Arkadiusz K Kuczaj ◽  
...  

E-vapor products (EVP) have become popular alternatives for cigarette smokers who would otherwise continue to smoke. EVP research is challenging and complex, mostly because of the numerous and rapidly evolving technologies and designs as well as the multiplicity of e-liquid flavors and solvents available on the market. There is an urgent need to standardize all stages of EVP assessment, from the production of a reference product to e-vapor generation methods and from physicochemical characterization methods to nonclinical and clinical exposure studies. The objective of this review is to provide a detailed description of selected experimental setups and methods for EVP aerosol generation and collection and exposure systems for their in vitro and in vivo assessment. The focus is on the specificities of the product that constitute challenges and require development of ad hoc assessment frameworks, equipment, and methods. In so doing, this review aims to support further studies, objective evaluation, comparison, and verification of existing evidence, and, ultimately, formulation of standardized methods for testing EVPs.


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