Begell House Inc.
Atomization and Sprays
AAS
1044-5110
27
12
2017
NUMERICAL SIMULATION OF HIGH-PRESSURE FUEL SPRAY BY USING A NEW HYBRID BREAKUP MODEL
999-1023
10.1615/AtomizSpr.2017019779
Wenliang
Qi
College of Power and Energy Engineering, Harbin Engineering University, Harbin 150001,
China
Wenping
Zhang
College of Power and Energy Engineering, Harbin Engineering University, Harbin 150001,
China
Pingjian
Ming
College of Power and Energy Engineering, Harbin Engineering University, Harbin 150001,
China
Ming
Jia
Key Laboratory of Ocean Energy Utilization and Energy Conservation of
Ministry of Education, School of Energy and Power Engineering, Dalian
University of Technology, Dalian, 116024, P.R. China
Ye
Peng
College of Power and Energy Engineering, Harbin Engineering University, Harbin 150001,
China
diesel spray
spray breakup model
numerical simulation
general transport equation analysis
The aim of this research is to develop a new hybrid breakup model by considering the influence of turbulence inside
the nozzle and modifying the second breakup model. The model distinguishes between primary breakup and secondary
breakup. In modeling primary breakup, the turbulence perturbation was characterized by the turbulence characteristic length and time scales, and the weight coefficient was used when incorporating into the primary breakup model (KH). For secondary breakup, a competition between the Kelvin–Helmholtz (KH) and Rayleigh–Taylor (RT) breakup mechanisms was adopted. In addition to the two breakup mechanisms above, the Taylor analogy breakup (TAB) was also selected as a third competing mechanism in this process. The modified FVM (finite volume method) method was used to solve fluid-flow equations and numerical simulations were performed with the in-house software GTEA (General
Transport Equation Analysis). Four breakup models including the TAB, cascade atomization and drop breakup (CAB),
Kelvin–Helmholtz Rayleigh–Taylor (KH-RT) and the new hybrid breakup (hybrid) were implemented in GTEA software.
In order to validate the new hybrid model, comparisons of the predictions from the present model with experimental
data and predictions from the other three models were conducted. The results indicate that prediction from the
new hybrid model gives better agreement with experimental measurements than those of the previous model.
A PARAMETRICAL STUDY OF THE BREAKUP AND ATOMIZATION PROCESS OF TWO IMPINGING LIQUID JETS
1025-1040
10.1615/AtomizSpr.2017020941
Can
Ruan
School of Aerospace Engineering, Xiamen University, Xiamen, Fujian, People's Republic of
China, 361005; Key Laboratory for Power Machinery and Engineering of M.O.E., Shanghai Jiao Tong University, Shanghai, People's Republic of China, 200240
Fei
Xing
School of Aerospace Engineering, Xiamen University, Xiamen, Fujian Province,
China, 361102
Yue
Huang
School of Aerospace Engineering, Xiamen University, Xiamen, Fujian, People's Republic of
China, 361005
Leilei
Xu
Key Laboratory for Power Machinery and Engineering of M.O.E., Shanghai Jiao Tong
University, Shanghai, People's Republic of China, 200240
Xingcai
Lu
Key Laboratory for Power Machinery and Engineering of M.O.E., Shanghai Jiao Tong
University, Shanghai, People's Republic of China, 200240
impinging jets
volume of fluid
liquid rocket engine
atomization
The breakup and atomization characteristics of two impinging liquid jets under various operating conditions were
numerically investigated with tree-based adaptive mesh refinement (AMR) and volume of fluid (VOF) methods. Jet
velocity, impingement angle, and jet momentum ratio were varied to provide a wide range of jet operating conditions.
Results indicate that the overall spray patterns vary dramatically with the change of jet velocity. The impingement angle has a great influence on the instability characteristics of the impact wave, and there exists an excessive impingement angle which may lead to the backflow of the liquid fuel, thus causing serious wall ablation when an impinging-type injector is used in liquid rocket engine combustors. Furthermore, the liquid sheet deviates from the symmetry axis when the velocities of the two jets are not the same, leading to a bow-shaped liquid sheet.
NONLINEAR SPATIAL INSTABILITY OF A SLENDER VISCOUS JET
1041-1061
10.1615/AtomizSpr.2018020689
Li-Jun
Yang
School of Astronautics, Beihang University, Beijing 100191, China; Beijing Advanced Innovation Center for Big Data-Based Precision Medicine,
School of Medicine and Engineering, Beihang University, Beijing 100083,
China
Tao
Hu
Beijing University of Aeronautics and Astronautics, Beijing, 100191, China
Pi-Min
Chen
AVIC Aviation Powerplant Research Institute, Zhuzhou, 412002, China
Han-Yu
Ye
Beijing University of Aeronautics and Astronautics, Beijing, 100191, China
spatial instability
one-dimensional equations
slender viscous jet
perturbation analysis
A perturbation analysis combined with one-dimensional equations is carried out to study the nonlinear spatial instability of a slender viscous jet. The solutions and wave profiles of the second order to third order have been presented. The result indicates that, as the perturbation expression proceeds to higher orders, the main swellings become narrow and the secondary swellings are flattened, resulting in the formation of a level liquid ligament. In addition, there exist two different nonlinear regions, named herein as the strong nonlinear region and the weak nonlinear region. The division of the two regions can be explained as a result of the interactions between the higher order harmonics transferred from lower orders and the inherent higher order disturbances. In addition, as Weber number decreases or Reynolds number increases, the growth rate of the jet increases significantly; the nonlinear amplitudes increase in the strong nonlinear region but remain constant in the weak nonlinear region, resulting in a shorter breakup length and a nearly identical waveform. The critical frequency, below which the jet is in the strong nonlinear region and above which it is in the weak nonlinear region, is not affected by Weber number but decreases noticeably as the Reynolds number reduces to less than 10. The theoretical waveforms are in agreement with previous experiments and simulations.
OPTIMIZATION OF THE SPRAY COOLING PARAMETERS FOR A HEAT SINK BY THE TAGUCHI METHOD
1063-1075
10.1615/AtomizSpr.2018019951
Faruk
Yesildal
Department of Mechanical Engineering, Agri Ibrahim Cecen University, Agri 04100, Turkey
Kenan
Yakut
Department of Mechanical Engineering, Atatürk University, Erzurum 25240, Turkey
spray cooling
air-assisted atomization
Taguchi experimental design
nonboiling regime
Spray cooling is among the most important technologies available for the removal of energy with high heat capacity.
Spray cooling has many geometrical and operational variable parameters. Therefore, the predictive capabilities are
quite limited and the exact mathematical expression is very difficult. For this reason, there is a need for experimental
studies using statistical methods. In this study, the spray cooling parameters with a hexagonal finned heat sink were
investigated in the nonboiling regime. Experiments were performed at a constant surface temperature. The effects of
the nozzle-to-heat-sink distance, the widths and heights of the fins, the distance between fins in the x and y directions, air-water flow rates, and spraying time on the heat transfer have been investigated by the Taguchi experimental design method. As a performance characteristic, the Nusselt number has been regarded and the L18 (21 × 37) orthogonal array chosen as an experimental layout for the eight parameters. The optimized results have been found to be a nozzle-surface distance of 400 mm, fin height of 10 mm, fin width of 36 mm, distance between fins of 15 mm in the x direction and 10 mm in the y direction, an air flow rate of 3.6 m3/h, water flow rate of 0.03 m3/h, and a spraying time of 5 s. The impact of ranking parameters on spray cooling heat transfer was examined. The most effective parameter was found to be spraying time.
SOOT FORMATION CHARACTERISTICS OF PALM METHYL ESTER SPRAY FLAMES IN COUNTERFLOW SUSTAINED BY METHANE/AIR PREMIXED FLAME
1077-1087
10.1615/AtomizSpr.2018021075
Jun
Hayashi
Department of Energy Conversion Science, Kyoto University, Yoshida-honmachi, Sakyo-ku,
Kyoto, 6068501, Japan; Department of Mechanical Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 5650871, Japan
Nozomu
Hashimoto
Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa,
2400196, Japan; Division of Mechanical and Space Engineering, Hokkaido University, Nishi 8, Kita 13, Kita-ku, Sapporo, Hokkaido, 0608628, Japan
Hiroyuki
Nishida
Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa,
2400196, Japan; Tokyo University of Agriculture and Technology, Koganei, Tokyo, 184-8588, Japan
Fumiteru
Akamatsu
Department of Mechanical Engineering, Osaka University, Japan
palm methyl ester
spray flames
counterflow
soot
two-dimensional laser-induced incandescence
To evaluate the potential of palm methyl ester (PME) as an alternative fuel, the characteristics of soot formation in PME spray flames were experimentally investigated. The spatial distribution of the soot volume fraction in a PME spray flame, which was stabilized in a laminar counterflow field using a stable lean premixed flame, was measured using
two-dimensional laser-induced incandescence (2D-LII). The structure of the PME spray flames and the characteristics
of the soot formation were compared with those of diesel fuel and n-dodecane. The results showed that PME and n-
dodecane exhibited similar structures of spray flame and indicated time-averaged and instantaneous characteristics of
soot formation, despite only PME containing oxygen in its molecular structure. In contrast, the time-averaged soot
volume fraction in the PME spray flame was much smaller than that of the diesel fuel because the diesel fuel contains
some polycyclic aromatic hydrocarbon components. These results suggest that the straight chain structure in PME is
the primary cause of the lower volume fraction of soot in the PME spray flames than that in the diesel fuel spray flames.
Index, Volume 27, 2017
1088-1096
10.1615/AtomizSpr.v27.i12.60