Effects of Injection Conditions and Oxygen Mole Fraction on Ignition Process of a Fuel Spray

Surface tensions of electromagnetically levitated liquid Ti-samples were measured under the influence of oxygen. For this purpose, Ti-O samples were prepared by adding different amounts of TiO2 powder to pure Ti. The surface tension was found to strongly depend on the bulk oxygen mole fraction determined by chemical analysis. The results could be described by a simple model presented in the present work. In this model the Butler equation is applied and the formation of TiO2 – associates are taken into account. Non-ideal interactions ΔH≠0 between titanium and the associates also need to be taken into account. Good agreement with the experimental data is evident and also with a different model developed earlier by us.

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Effects of intake oxygen mole fraction on the near-stoichiometric combustion and emission characteristics of a CI (compression ignition) engine

Energy ◽

10.1016/j.energy.2014.12.023 ◽

2015 ◽

Vol 80 ◽

pp. 677-686 ◽

Cited By ~ 5

Author(s):

Junepyo Cha ◽

Sungjun Yoon ◽

Seokhwon Lee ◽

Sungwook Park

Keyword(s):

Mole Fraction ◽

Emission Characteristics ◽

Compression Ignition ◽

Compression Ignition Engine ◽

Oxygen Mole Fraction

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C110 Modeling of Ignition Process in a Diesel Fuel Spray

Proceedings of thermal engineering conference ◽

10.1299/jsmeptec.2001.0_119 ◽

2001 ◽

Vol 2001 (0) ◽

pp. 119-120

Author(s):

Hidenori KOSAKA ◽

Tomohiro MINAGAWA ◽

Takeyuki KAMIMOTO

Keyword(s):

Diesel Fuel ◽

Fuel Spray ◽

Ignition Process

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Ignition process of fuel spray injected into high pressure high temperature atmosphere

Symposium (International) on Combustion ◽

10.1016/s0082-0784(88)80301-1 ◽

1988 ◽

Vol 21 (1) ◽

pp. 695-702 ◽

Cited By ~ 15

Author(s):

Jun'ichi Sato ◽

Katsuyuki Konishi ◽

Hiroshi Okada ◽

Takashi Niioka

Keyword(s):

High Pressure ◽

High Temperature ◽

Fuel Spray ◽

Ignition Process ◽

High Pressure High Temperature

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A Model of CoO Oxidation

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19932853 ◽

1993 ◽

Vol 58 (12) ◽

pp. 2853-2866

Author(s):

Marcela Tkadlecová

Keyword(s):

Experimental Data ◽

Temperature Dependence ◽

Mole Fraction ◽

Rate Constant ◽

Surface Reaction ◽

Energy Of Activation ◽

The Given ◽

Oxygen Mole Fraction

A model of CoO oxidation was proposed which assumes the diffusion of cobalt atoms from the bulk of crystalline to its surface and the surface reaction of these atoms with surrounding oxygen. It depends on the comparison of expressions D/a20 and kxox/a0 to what extent these two processes will manifest themselves for the given temperature and oxygen mole fraction xox. The value of diffusivity D and its temperature dependence were estimated from the data in literature and the size of crystallites a0 from roentgenographic measurements. The value of rate constant of surface reaction k and its energy of activation were evaluated from experimental data for CoO oxidation.

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Effect of Oxygen Mole Fraction on Static Properties of Pressure-Sensitive Paint

Sensors ◽

10.3390/s21041062 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1062

Author(s):

Tomohiro Okudera ◽

Takayuki Nagata ◽

Miku Kasai ◽

Yuji Saito ◽

Taku Nonomura ◽

...

Keyword(s):

Partial Pressure ◽

Mole Fraction ◽

Ambient Pressure ◽

Low Pressure ◽

Pressure Sensitive Paint ◽

Partial Pressure Of Oxygen ◽

Static Properties ◽

Pressure Sensitive ◽

High Partial Pressure ◽

Oxygen Mole Fraction

The effects of the oxygen mole fraction on the static properties of pressure-sensitive paint (PSP) were investigated. Sample coupon tests using a calibration chamber were conducted for poly(hexafluoroisopropyl methacrylate)-based PSP (PHFIPM-PSP), polymer/ceramic PSP (PC-PSP), and anodized aluminum PSP (AA-PSP). The oxygen mole fraction was set to 0.1–100%, and the ambient pressure (Pref) was set to 0.5–140 kPa. Localized Stern–Volmer coefficient Blocal increased and then decreased with increasing oxygen mole fraction. Although Blocal depends on both ambient pressure and the oxygen mole fraction, its effect can be characterized as a function of the partial pressure of oxygen. For AA-PSP and PHFIPM-PSP, which are low-pressure- and relatively low-pressure-type PSPs, respectively, Blocal peaks at PO2ref<12 kPa. In contrast, for PC-PSP, which is an atmospheric-pressure-type PSP in the investigated range, Blocal does not have a peak. Blocal has a peak at a relatively high partial pressure of oxygen due to the oxygen permeability of the polymer used in the binder. The peak of SPR, which is the emission intensity change with respect to normalized pressure fluctuation, appears at a lower partial pressure of oxygen than that of Blocal. This is because the intensity of PSP becomes quite low at a high partial pressure of oxygen even if Blocal is high. Hence, the optimal oxygen mole fraction depends on the type of PSP and the ambient pressure range of the experiment. This optimal value can be found on the basis of the partial pressure of oxygen.

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The Evolutions in Time of Probability Density Functions of Polydispersed Fuel Spray-The Continuous Mathematical

10.21203/rs.3.rs-777585/v1 ◽

2021 ◽

Author(s):

Shlomo Hareli ◽

OPhir Nave ◽

Vladimir Gol'dshtein

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Combustion Process ◽

The Self ◽

Fuel Spray ◽

Ignition Process ◽

Simplified Models ◽

Short Period ◽

The Mean

Abstract The dynamics of the particle-size distribution of the polydispersed fuel spray are important for the evaluation of the combustion process. In this paper, we presented the particle-size distribution change in time which gives a new insight into the behavior of the droplets during the self-ignition process. Semenov was the first to shows that self-ignition in the homogeneous case can be qualitatively and even quantitatively described by simplified models \cite{first_Math_Semenov_1928}. A simplified model of the polydisperse spray is used for a study of combustion processes near the initial region. This model involves a time-dependent function of the particle-size distribution. Such simplified models are particularly helpful in understanding qualitatively the effect of various sub-processes. Our main results show that during the self-ignition process, the droplets' radii decrease as expected, and the number of smaller droplets increases in inverse proportion to the radius. An important novel result (visualized by graphs) demonstrates that the mean radius of the droplets, at first increases for a relatively short period of time, and that is then followed by the expected decrease. It means that the maximum of the mean radius is not located at the beginning of the process as expected. We only have a heuristic explanation of this phenomenon, but an analytic study is planned for the future. Our modified algorithm is superior to the well known `parcel' approach because it is much more compact, it permits an analytical study since the right-hand sides are smooth, and thus eliminates the need for a numerical algorithm transitioning from one parcel to another, The method explain herein can be applied to any approximation of the particle-size distribution, and it involves comparatively negligible computation time.

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The Evolutions in Time of Probability Density Functions of Polydispersed Fuel Spray—The Continuous Mathematical Model

Applied Sciences ◽

10.3390/app11209739 ◽

2021 ◽

Vol 11 (20) ◽

pp. 9739

Author(s):

Shlomo Hareli ◽

Ophir Nave ◽

Vladimir Gol’dshtein

Keyword(s):

Mathematical Model ◽

Combustion Process ◽

Computation Time ◽

Fuel Spray ◽

Ignition Process ◽

Experimental Distribution ◽

Elegant Method ◽

Short Period ◽

The Right ◽

The Mathematical Model

The dynamics of the particle size distribution (PSD) of polydispersed fuel spray is important in the evaluation of the combustion process. A better understanding of the dynamics can provide a tool for selecting a PSD that will more effectively meet the needs of the system. In this paper, we present an efficient and elegant method for evaluating the dynamics of the PSD. New insights into the behaviour of polydispersed fuel spray were obtained. A simplified theoretical model was applied to the experimental data and a known approximation of the polydispersed fuel spray. This model can be applied to any distribution, not necessarily an experimental distribution or approximation, and involves a time-dependent function of the PSD. Such simplified models are particularly helpful in qualitatively understanding the effects of various sub-processes. Our main results show that during the self-ignition process, the radii of the droplets decreased as expected, and the number of smaller droplets increased in inverse proportion to the radius. An important novel result (visualised by graphs) demonstrates that the mean radius of the droplets initially increases for a relatively short period of time, which is followed by the expected decrease. Our modified algorithm is superior to the well-known `parcel’ approach because it is much more compact; it permits analytical study because the right-hand sides of the mathematical model are smooth, and thus eliminates the need for a numerical algorithm to transition from one parcel to another. Moreover, the method can provide droplet radii resolution dynamics because it can use step functions that accurately describe the evolution of the radii of the droplets. The method explained herein can be applied to any approximation of the PSD, and involves a comparatively negligible computation time.

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