Wei Zhong¹, Zhenfang Xin², Lihua Wang^1,*, Haiping Liu²

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.2, pp. 1427-1453, 2024, DOI:10.32604/cmes.2023.031271

Abstract Flash boiling atomization (FBA) is a promising approach for enhancing spray atomization, which can generate a fine and more evenly distributed spray by increasing the fuel injection temperature or reducing the ambient pressure. However, when the outlet speed of the nozzle exceeds 400 m/s, investigating high-speed flash boiling atomization (HFBA) becomes quite challenging. This difficulty arises from the involvement of many complex physical processes and the requirement for a very fine mesh in numerical simulations. In this study, an HFBA model for gasoline direct injection (GDI) is established. This model incorporates primary and secondary atomization, as well as vaporization and… More >

Renganathan Manimaran^a, Rajagopal Thundil Karuppa Raj^b,*

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-9, 2014, DOI:10.5098/hmt.5.2

Abstract Diesel engine combustion modeling presents a challenging task with the formation and breakup of spray into droplets. In this work, 3D-CFD computations are performed to understand the behaviour of spray droplet diameter and temperature during the combustion by varying the swirl ratio and injection timing. After the validation and grid and time independency tests, it is found that increase in swirl ratio from 1.4 to 4.1 results in peak pressure rise of 8 bar and an advancement of injection timing from 6 deg bTDC to 20 deg bTDC results in increase of peak pressure by 15 %. More >

Vijayakumar Thulasi, R. Thundil Karuppa Raj^*

Frontiers in Heat and Mass Transfer, Vol.10, pp. 1-9, 2018, DOI:10.5098/hmt.10.33

Abstract Diethyl ether is one of the potential alternative fuels for the high speed compression ignition engines that can replace the existing neat diesel fuel. It is well known that the combustion characteristic of a compression ignition engine is highly influenced by the fuel spray structure formed during the injection process. In this paper the spray structure formation for the diethyl ether fuel is studied numerically, using the discrete phase model and it is compared with the neat diesel fuel. The spray is investigated in a constant volume chamber maintained at 30 bar pressure. The fuel is injected into the chamber… More >

Dongling Yu¹, Huiling Zhang¹, Xu Zeng¹, Dahai Liao^1,*, Nanxing Wu^2,*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.3, pp. 569-586, 2021, DOI:10.32604/fdmp.2021.014711

Abstract In order to reveal the intrinsic fluid-dynamic mechanisms of a pressure-swirl nozzle used for Si₃N₄ dry granulation, and effectively predict its external spray characteristics, the dynamics of air-atomized liquid two-phase flow is analyzed using a VOF (Volume of Fraction) method together with the modified realizable k-ε turbulence model. The influence of nozzle orifice shape on velocity distribution, pressure distribution is studied. The results show that the pressure difference in a convergent conical nozzle is the largest with a hollow air core being formed in the nozzle. The corresponding velocity of atomized liquid at nozzle orifice is the largest. Using a… More >

Mikhail G. Shatrov¹, Valery I. Malchuk², Andrey Y. Dunin^1,*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.4, pp. 747-760, 2020, DOI:10.32604/fdmp.2020.08991

Abstract This paper reports a laboratory investigation of the fuel injection process in a diesel engine. The atomization process of the considered fuel (a hydrocarbon liquid) and the ensuing mixing with air is studied experimentally under high-pressure conditions. Different types of injector nozzles are examined, including (two) new configurations, which are compared in terms of performances to a standard injector manufactured by the Bosch company. For the two alternate con- figurations, the intake edges of one atomizing hole (hole No. 1) are located in the sack volume while for the other (hole No. 2) they are located on the locking cone… More >

M.S. Raju & Dan Bulzan

The International Conference on Computational & Experimental Engineering and Sciences, Vol.19, No.4, pp. 109-110, 2011, DOI:10.3970/icces.2011.019.109

Abstract The paper presents the results from a validation study undertaken as a part of the NASA's fundamental aeronautics initiative on high altitude emissions in order to assess the accuracy of several atomization models used in both sub-cooled and superheat spray calculations. As a part of this investigation we have undertaken the validation based on four different cases to investigate the spray charactereristics of (1) a ashing jet generated by the sudden release of pressurized R134A from cylindrical nozzle, (2) a liquid jet atomizing in a subsonic cross ow, (3) a Parker-Hannin pressure swirl atomizer, and (4) a single-element LDI (Lean… More >

Hun Jung¹, Jin Seok Kim¹, Jeong Soo Kim², Jeong Park³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.11, No.4, pp. 125-126, 2009, DOI:10.3970/icces.2009.011.125

Abstract An injector plays an important role in the process of an efficient combustion in liquid-rocket engines (LRE) because it affects the evaporation rate of liquid fuel through spatial distribution and atomization of spray droplets. This paper is focused on the injection performance of a small LRE-Injector by employing the spray characteristic parameters made up of the velocity components, mean diameter, turbulence intensity, span (width of drop size distribution), number density, and volume flux of spray droplets. An experimental investigation is carried out with the aid of a dual-mode phase Doppler anemometry (DPDA) according to the injection pressure variation and along… More >

Ashraf Balabel¹

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.4, pp. 283-302, 2013, DOI:10.3970/cmes.2013.095.283

Abstract This paper presents the numerical results obtained from the numerical simulation of turbulent liquid jet atomization due to three distinctly different types of liquid jets/air orientations; namely, coflow jet, coaxial jet and the combined coflow-coaxial jet. The applied numerical method, developed by the present authors, is based on the solution of the Reynolds-Averaged Navier Stokes (RANS) equations for time-dependent, axisymmetric and incompressible two-phase flow in both phases separately and on regular and structured cell-centered collocated grids using the control volume approach. The transition from one phase to another is performed through a consistent balance of the interfacial dynamic and kinematic… More >

Chun-Lang Yeh¹

CMES-Computer Modeling in Engineering & Sciences, Vol.39, No.2, pp. 179-200, 2009, DOI:10.3970/cmes.2009.039.179

Abstract In this research, the atomization process of a nanojet is investigated by molecular dynamics simulation. Liquid argon nanojet made of 44000 Lennard-Jones molecules is examined under various simulation parameters to study their influence on the nanojet atomization process. Snapshots of the molecules, evolution of the density field, and evolution of the intermolecular force are analyzed. The present simulation results can provide insight into the fundamental mechanism of the atomization process and will be helpful for the design of nanojet devices such as nano-printer or nano-sprayer. More >