Temporal properties of secondary drop breakup in the bag-stamen breakup regime

2013 ◽  
Vol 25 (5) ◽  
pp. 054102 ◽  
Author(s):  
Hui Zhao ◽  
Hai-Feng Liu ◽  
Jian-Liang Xu ◽  
Wei-Feng Li ◽  
Kuang-Fei Lin
Keyword(s):  
Drop Breakup ◽  
Temporal Properties ◽  
Secondary Drop

Secondary-Drop-Breakup Simulation Integrated With Fuel-Breakup Simulation Near Injector Outlet

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Eiji Ishii ◽  
Masanori Ishikawa ◽  
Yoshihiro Sukegawa ◽  
Hiroshi Yamada
Keyword(s):  
Liquid Film ◽  
Particle Method ◽  
Liquid Films ◽  
Fuel Spray ◽  
Fuel Injector ◽  
Drop Breakup ◽  
Free Surfaces ◽  
Collision Type ◽  
Automobile Engines ◽  
Secondary Drop

The fuel spray of an injector for automobile engines contains multiscale free surfaces: liquid films formed at the fuel-injector outlet, ligaments generated by liquid-film breakup, and droplets generated from the ligaments within the secondary-drop-breakup region. To simulate these multiscale free surfaces, we developed a method that combines two types of simulation. The liquid-film breakup near the injector outlet was simulated by using a particle method, and the secondary-drop breakup after the liquid-film breakup was simulated by using a discrete droplet model (DDM). The injection conditions of DDM were the distributions of droplet diameters and velocities calculated in the liquid-film-breakup simulation. We applied our method to simulate the spray from a collision-type fuel injector. The simulated liquid-film breakup near the injector outlet and behavior of the secondary-drop breakup qualitatively agreed with measurements. Furthermore, the errors of the mean droplet diameters between the simulations and the measurements were less than 12%. This shows that our method is effective for fuel spray simulation.

SECONDARY DROP BREAKUP IN SWIRL ATOMIZERS

2002 ◽  
Vol 12 (5-6) ◽  
pp. 615-628
Author(s):  
Yuriy Khavkin
Keyword(s):  
Drop Breakup ◽  
Secondary Drop

Short Spray Penetration for Direct Injection Gasoline Engines With Secondary-Drop-Breakup Simulation Integrated With Fuel-Breakup Simulation

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Eiji Ishii ◽  
Hideharu Ehara ◽  
Motoyuki Abe ◽  
Toru Ishikawa
Keyword(s):  
High Speed ◽  
Direct Injection ◽  
Grid Method ◽  
Liquid Column ◽  
Fuel Spray ◽  
Drop Breakup ◽  
Spray Penetration ◽  
Fuel Injectors ◽  
Gasoline Engines ◽  
Secondary Drop

Direct injection gasoline engines have both better engine power and fuel efficiency than port injection gasoline engines. However, direct injection gasoline engines also emit more particulate matter (PM) than port injection gasoline engines do. To decrease PM, fuel injectors with short spray penetration are required. More effective fuel injectors can be preliminarily designed by numerically simulating fuel spray. We previously developed a fuel-spray simulation. Both the fuel flow within the flow paths of an injector and the liquid column at the injector outlet were simulated by using a grid method. The liquid-column breakup was simulated by using a particle method. The motion of droplets within the air/fuel mixture (secondary-drop-breakup) region was calculated by using a discrete droplet model (DDM). In this study, we applied our fuel-spray simulation to sprays for the direct injection gasoline engines. Simulated spray penetrations agreed relatively well with measured spray penetrations. Velocity distributions at the outlet of three kinds of nozzles were plotted by using a histogram, and the relationship between the velocity distributions and spray penetrations was studied. We found that shrinking the high-speed region and making the velocity-distribution uniform were required for short spray penetration.

Temporal properties of drop breakup in the shear breakup regime

1997 ◽  
Vol 23 (4) ◽  
pp. 651-669 ◽  
Author(s):  
W.-H. Chou ◽  
L.-P. Hsiang ◽  
G.M. Faeth
Keyword(s):  
Drop Breakup ◽  
Temporal Properties

Auditory Training to Improve Speech Perception and Self-Efficacy in Aging Adults

2020 ◽  
Vol 63 (4) ◽  
pp. 1270-1281
Author(s):  
Leah Fostick ◽  
Riki Taitelbaum-Swead ◽  
Shulamith Kreitler ◽  
Shelly Zokraut ◽  
Miriam Billig
Keyword(s):  
Speech Perception ◽  
Self Efficacy ◽  
Temporal Order Judgment ◽  
Auditory Training ◽  
Intensity Discrimination ◽  
Training Design ◽  
Auditory Temporal Processing ◽  
Temporal Properties ◽  
Computer Based ◽  
Aging Adults

Purpose Difficulty in understanding spoken speech is a common complaint among aging adults, even when hearing impairment is absent. Correlational studies point to a relationship between age, auditory temporal processing (ATP), and speech perception but cannot demonstrate causality unlike training studies. In the current study, we test (a) the causal relationship between a spatial–temporal ATP task (temporal order judgment [TOJ]) and speech perception among aging adults using a training design and (b) whether improvement in aging adult speech perception is accompanied by improved self-efficacy. Method Eighty-two participants aged 60–83 years were randomly assigned to a group receiving (a) ATP training (TOJ) over 14 days, (b) non-ATP training (intensity discrimination) over 14 days, or (c) no training. Results The data showed that TOJ training elicited improvement in all speech perception tests, which was accompanied by increased self-efficacy. Neither improvement in speech perception nor self-efficacy was evident following non-ATP training or no training. Conclusions There was no generalization of the improvement resulting from TOJ training to intensity discrimination or generalization of improvement resulting from intensity discrimination training to speech perception. These findings imply that the effect of TOJ training on speech perception is specific and such improvement is not simply the product of generally improved auditory perception. It provides support for the idea that temporal properties of speech are indeed crucial for speech perception. Clinically, the findings suggest that aging adults can be trained to improve their speech perception, specifically through computer-based auditory training, and this may improve perceived self-efficacy.

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