Semi-empirical analysis of liquid fuel and fuel vapor distributions downstream of a plain-orifice injector with cross-stream air flow

1985 ◽  
Author(s):  
J. CHIN ◽  
A. LEFEBVRE
Keyword(s):  
Empirical Analysis ◽  
Liquid Fuel ◽  
Air Flow ◽  
Fuel Vapor ◽  
Semi Empirical

scholarly journals Semi-Empirical Analysis of Liquid Fuel Distribution Downstream of a Plain Orifice Injector Under Cross-Stream Air Flow

1982 ◽  
Author(s):  
Cao Ming-hua ◽  
Jiang Hong-kun ◽  
Chin Ju-shan
Keyword(s):  
Ambient Temperature ◽  
Empirical Analysis ◽  
High Velocity ◽  
Liquid Fuel ◽  
Air Flow ◽  
Liquid Sheet ◽  
Preliminary Design ◽  
Fuel Injector ◽  
Fuel Distribution ◽  
Semi Empirical

An improved semi-empirical analysis is presented for the liquid fuel distribution downstream of a plain orifice fuel injector under cross-stream airflow of uniform high velocity and constant ambient temperature. The analysis is based on a simplified “flat-fan spray” model (ε – ψ model). The ε – ψ model is proposed which assumes that the fuel injected through the orifice forms a flat-fan liquid sheet with an average fan angle 2 ψ0. Once the droplets have been formed, the trajectory of individual droplets determines the fuel distribution downstream. The validity of the analysis is confirmed by comparison of calculations based on the ε – ψ model and test data obtained from fuel distribution experiments under cross-stream air flow of ambient temperature. The agreement is shown to be very good. The semi-empirical analysis presented offers a very useful approach in the preliminary design of the fan air flow path portion of turbo-fan after-burners.

Forced ignition of dispersions of liquid fuel in turbulent air flow

2017 ◽  
Author(s):  
Pedro M. de Oliveira ◽  
Epaminondas Mastorakos ◽  
Patton M. Allison
Keyword(s):  
Liquid Fuel ◽  
Air Flow ◽  
Turbulent Air Flow

scholarly journals Calculation of flow characteristics of liquid fuel supplied through pressure jet atomizers of small-sized gas turbine engines

2021 ◽  
Vol 20 (2) ◽  
pp. 19-35
Author(s):  
N. I. Gurakov ◽  
I. A. Zubrilin ◽  
M. Hernandez Morales ◽  
D. V. Yakushkin ◽  
A. A. Didenko ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Liquid Fuel ◽  
Cone Angle ◽  
Flow Characteristics ◽  
Design Parameters ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Semi Empirical

The paper presents the results of studying the flow characteristics of liquid fuel in pressure jet atomizers of small-sized gas turbine engines with nozzle diameters of 0.4-0.6 mm for various operating and design parameters. The study was carried out using experimental measurements, semi-empirical correlations and CFD (computational fluid dynamics) methods. The Euler approach, the volume- of- fluid (VOF) method, was used to model multiphase flows in CFD simulations. Good agreement was obtained between experimental and predicted data on the fuel coefficient and the primary spray cone angle at the nozzle outlet. Besides, the assessment of the applicability of semi-empirical techniques for the nozzle configurations under consideration is given. In the future, the flow characteristics in question (the nozzle flow rate, the fuel film thickness, and the primary spray cone angle) can be used to determine the mean diameter of the droplets (SMD) required to fully determine the boundary conditions of fuel injection when modeling combustion processes in combustion chambers of small-sized gas turbine engines.

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.

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.

Semiempirical Analysis of Liquid Fuel Distribution Downstream of a Plain Orifice Injector Under Cross-Stream Air Flow

1982 ◽  
Vol 104 (4) ◽  
pp. 788-795 ◽  
Author(s):  
Ming-hua Cao ◽  
Hong-kun Jiang ◽  
Ju-shan Chin
Keyword(s):  
Ambient Temperature ◽  
Test Data ◽  
High Velocity ◽  
Liquid Fuel ◽  
Air Flow ◽  
Liquid Sheet ◽  
Flow Path ◽  
Preliminary Design ◽  
Fuel Injector ◽  
Fuel Distribution

An improved semiempirical analysis is presented for the liquid fuel distribution downstream of a plain orifice fuel injector under a cross-stream air flow of uniform high velocity and constant ambient temperature. The analysis is based on a simplified “flat-fan spray” model (ε–ψ model). A ε–ψ model is proposed which assumes that the fuel injected through the orifice forms a flat-fan liquid sheet with an average fan angle 2ψ0. Once the droplets have been formed, the trajectory of individual droplets determines the fuel distribution downstream. The validity of the analysis is confirmed by comparison of calculations based on the ε–ψ model and test data obtained from fuel distribution experiments under cross-stream air flow of ambient temperature. The agreement is shown to be very good. The semiempirical analysis presented offers a very useful approach in the preliminary design of the fan air flow path portion of turbofan afterburners.

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