Models for droplet transient heating: Effects on droplet evaporation, ignition, and break-up

Sazhin, Sergei; Abdelghaffar, W.A.; Sazhina, Elena; Heikal, Morgan

doi:10.1016/j.ijthermalsci.2005.02.004

Cited by 103 publications

(89 citation statements)

References 45 publications

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“…This was due to the fact that the effect of temperature became lower as the mass quantity (diesel+ CNG) increased. The findings of this work on penetration rate (liquid phase under evaporation) with time agree with both Kennaird et al [17] and Sazhin et al [16] who found that the penetration was linear with time. The main reasons for the vapour jet transport was the losses of the momentum of the jet by the surrounding air motion as suggested by [25], [26].…”

Section: E Spray Tip Penetration Measurementsupporting

confidence: 92%

“…(at 0.75 ms). At the upstream region, the discrepancy of the penetration was quite small between their different injection pressures (18,16, and 14 bar), but this differences became more significant as time elapsed. This phenomenon was thought to be caused by the high flow rate leading to a high momentum of the CNG jet.…”

Section: Diesel Spray Characteristic Calculationsmentioning

confidence: 93%

“…Fig. 4 shows the Schlieren images of the CNG jet under both ambient and different injection pressures (18,16, and 14 bar), the time intervals from 0.25 ms to 1.25ms at increments of 0.25 ms. As shown in the jet images, the injection pressure had a large influence on the jet structure as expected [10], [23], [24]. However, with increased of the injection pressures, the delivery time was reduced.…”

Section: Diesel Spray Characteristic Calculationsmentioning

confidence: 99%

“…Different methods were used in previous studies for achieving representative temperature conditions in the rig e.g. some used direct heating of the walls (bottom) of the test rig [16], while others used an electric heater inside the plate. In this study, a controlled electric heater was used to heat the bottom plate.…”

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confidence: 99%

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Spray Characteristics and Wall Impingement of Diesel-CNG Dual Fuel Jet Using Schlieren Imaging Technique

Ismael¹,

Heikal²,

Bahroom³

2015

IJMMM

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.my).the natural gas inside the engine. In addition, this system does not favor the two-stroke engine due to the escape of some of the natural gas fuel into the exhaust [3]. The second method of using natural gas in diesel engines is the direct injection of natural gas near to the diesel fuel spray into the combustion chamber [4]. Thus a full stratification of the fuel-air mixture can be obtained with good flammability over the entire load range.Recently, successful operation has been demonstrated by applying this method using a prototype co-injector [5], resulting in diesel-gas two phase mixtures which were then injected into the chamber. The authors recommended that the jet penetration should be imaged and characterized to further understand the complex two-phase flow phenomena. It appears that direct injection of natural gas with diesel pilot ignition is one of the most promising ways of meeting the energy crises and emissions regulation, analogous to the benefits provided by a common rail high pressure direct injection engine.Actually, the development of high performance natural gas DIEs is unclear as the macroscopic characteristics of the diesel-CNG dual fuel jet which differs considerably from that of diesel fueled compression ignition (CI) and spark ignition (SI) engines. In diesel-CNG dual fuel engine, the performance of the engine is influence significantly by the quality of the diesel fuel sprays and CNG jet propagation. Those characteristics can be classified into two basic categories: Macroscopic and microscopic. The first one, which involves spray tip penetration, spray cone-angle, and their derivatives and the second, involves droplet velocity, droplet size, size distribution and air fuel ratio [6]. Improvement of the diesel-CNG dual fuel jet characteristics such as jet tip penetration, jet cone angle and jet velocity in turn determine the diesel-CNG dual fuel combustion process and the associated formation of pollutants. In addition, these characteristics not only aim to improve the engine efficiency, but also assist the understanding of parameters used to judge fuel spray performance [7]. For example, the spray penetration length must neither be too long nor short in a combustion chamber. If too long, impingement could occur resulting in wetting of cylinder walls and/or piston crown [8]. Spray-wall impingement can be characterized into radial penetration along the wall and jet height. Improvement of those characteristics leads to enhance the mixture formation as well as the combustion process. The present work investigates the jet propagation of jets created by CNG and diesel injectors with aid of flow visualization. Based on the previous studies, it is well known that the injection strategy and the atomization play an important role for the diesel Materials, Mechanics and Manufacturing, Vol. 3, No. 3, August 2015 spray, and the mixture formation is largely dependent upon the droplet distribution and evaporation [9]. In contrast with diesel spray, natural gas does not have droplets and evapor...

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Section: E Spray Tip Penetration Measurementsupporting

confidence: 92%

Section: Diesel Spray Characteristic Calculationsmentioning

confidence: 93%

Section: Diesel Spray Characteristic Calculationsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Spray Characteristics and Wall Impingement of Diesel-CNG Dual Fuel Jet Using Schlieren Imaging Technique

Ismael¹,

Heikal²,

Bahroom³

2015

IJMMM

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“…The analysis by these authors was based on the numerical solution of the heat conduction equation inside droplets. An alternative approach was suggested and developed in [8][9][10][11][12][13]. In these papers both finite liquid thermal conductivity and recirculation inside droplets (via the effective thermal conductivity (ETC) model [14]) were taken into account by incorporating the analytical solution to the heat conduction equation inside the droplet into the numerical scheme.…”

Section: Introductionmentioning

confidence: 99%

Monodisperse monocomponent fuel droplet heating and evaporation

Kristyadi

Deprédurand

Castanet

et al. 2010

Fuel

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a b s t r a c tThe results of numerical and experimental studies of heating and evaporation of monodisperse acetone, ethanol, 3-pentanone, n-heptane, n-decane and n-dodecane droplets in an ambient air of fixed temperature and atmospheric pressure are reported. The numerical model took into account the finite thermal conductivity of droplets and recirculation inside them based on the effective thermal conductivity model and the analytical solution to the heat conduction equation inside droplets. The effects of interaction between droplets are taken into account based on the experimentally determined corrections to Nusselt and Sherwood numbers. It is pointed out that the interactions between droplets lead to noticeable reduction of their heating in the case of ethanol, 3-pentanone, n-heptane, n-decane and n-dodecane droplets, and reduction of their cooling in the case of acetone. Although the trends of experimentally observed droplet temperatures and radii are the same as predicted by the model taking into account the interaction between droplets, the actual values of the predicted droplet temperatures can differ from the observed ones by up to about 8 K, and the actual values of the predicted droplet radii can differ from the observed ones by up to about 2%. It is concluded that the effective thermal conductivity model, based on the analytical solution to the heat conduction equation inside droplets, can predict the observed average temperature of droplets with possible errors not exceeding several K, and observed droplet radii with possible errors not exceeding 2% in most cases. These results allow us to recommend the implementation of this model into CFD codes and to use it for multidimensional modelling of spray heating and evaporation based on these codes.

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Dynamic Decomposition of ODE Systems: Application to Modelling of Diesel Fuel Sprays

Bykov¹,

Goldfarb

Gol’dshtein

et al.

Model Reduction and Coarse-Graining Approaches for Multiscale Phenomena

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Models for droplet transient heating: Effects on droplet evaporation, ignition, and break-up

Cited by 103 publications

References 45 publications

Spray Characteristics and Wall Impingement of Diesel-CNG Dual Fuel Jet Using Schlieren Imaging Technique

Spray Characteristics and Wall Impingement of Diesel-CNG Dual Fuel Jet Using Schlieren Imaging Technique

Monodisperse monocomponent fuel droplet heating and evaporation

Dynamic Decomposition of ODE Systems: Application to Modelling of Diesel Fuel Sprays

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