Thermal stability and decomposition of diesel fuel under subcritical and supercritical conditions

Lin, Ronghong; Tavlarides, Lawrence L.

doi:10.1016/j.supflu.2012.12.026

Cited by 25 publications

(6 citation statements)

References 24 publications

(33 reference statements)

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“…This observation is in accordance with the results of the investigation by Lin and Tavlarides. 28 Thus, data collected during the cooling period could not be taken into account for the estimation of the critical temperature of the fluid.…”

Section: Methodsmentioning

confidence: 99%

Transition of diesel spray to a supercritical state under engine conditions

Wensing

Vogel

Götz³

2015

International Journal of Engine Research

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Process operating conditions of modern internal combustion engines can exceed the thermodynamic critical point of an injected liquid fuel. This raises the question of whether the fuel, or at least some of its components, transition to a supercritical state, even in the presence of an ambient gas. Further investigation is required for a better understanding of heat and mass transfer during the process of fuel injection in diesel engines. This article investigates the phase behavior of fuels and their components under supercritical conditions or when injected into such. After a brief review of the current state of research on the topic, we present our study of the phase behavior of three single-component liquids (n-heptane, n-dodecane, n-hexadecane) and their binary mixtures under supercritical conditions in a nitrogen environment using equations of state. In first experiments, these liquids along with a diesel fuel were successfully transitioned to supercritical states by applying engine-relevant but steady state conditions inside a high-pressure, high-temperature constant volume chamber. No influence of the ambient nitrogen on the phase behavior of the examined fluids was found. For further investigation, multicomponent fuels were injected into the chamber in a transient injection process and at typical engine-relevant time scales using a production-type diesel injector. The fuel sprays were examined with Mie scattering, laser-induced fluorescence, and shadowgraphic imaging. The information obtained confirms the presence of a supercritical state and a transcritical phase change. Areas of high density with pronounced fluctuations were visible. The theoretical review in combination with the results obtained from the experiments indicate that fuel injected under the high-pressure and high-temperature conditions, that are present in modern diesel engines at higher loads, does not evaporate but rather shows transition to a supercritical state with a disappearing phase border, but without boiling or changing density.

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Section: Methodsmentioning

confidence: 99%

Transition of diesel spray to a supercritical state under engine conditions

Wensing

Vogel

Götz³

2015

International Journal of Engine Research

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“…Also, effects of flow passage expansion and contraction and heat-transfer deterioration caused by surface coking deposition were conducted using the experiments and computational fluid dynamics (CFD) modeling. , Moreover, Eser and co-workers − have performed massive experiments on the surface decomposition coking deposition for various tube inner surface treatment methods, and the activity order of the tube surfaces toward carbon deposition was obtained. In recent years, thermal cracking of hydrocarbon fuels and biodiesel under sub- and supercritical conditions is still the hot point, especially on the surface influences and mechanism kinetics. − …”

Section: Introductionmentioning

confidence: 99%

Thermal and Element Analyses for Supercritical RP-3 Surface Coke Deposition under Stable and Vibration Conditions

Tao

et al. 2015

Energy Fuels

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Surface coke deposition mechanism on the supercritical aviation kerosene RP-3 was studied under stable and vibration conditions. The flowing RP-3 kerosene is pressurized to 5MPa, and heated from 400K to 723K in a stainless tube (I.D. =1.8mm, O.D. =2.2 mm, Length=1800mm) with a constant heat flux. The experimental mass flow rate is fixed at 3g/s (1180kg/ (m 2 s)) and the working fuel flows downward through the test tube. One-hour stable, one-hour with 600Hz vibration and long-duration with 566Hz vibration tube jam experiments were performed. The two vibration frequencies are close to the main frequencies of the combustion chamber vibration when it works. Flow resistance, heat transfer characteristics, coking amount and component analysis were compared between stable and vibration conditions. The results indicate that vibration can affect the coking distribution much more uniformly and extend the tube working time. Also, vibration inhibits the exponential growth of flow resistance by changing coke formation compared with the stable condition. Three obvious regions for heat transfer are considered during the long-duration vibration experiments. For coking elements analysis, trace elements of Cu have more apparent catalytic effects under vibration conditions. The elements Fe and Cr have higher content in the downstream section of the tube due to crushing caused by vibration. Nomenclature D diameter (m) f vibration frequency (Hz) h heat transfer coefficient (W m -2 K) L tube length (m) m mass flow rate (g/s) P pressure (kPa) q heat flux (kW/m 2 ) R(t) electronic resistivity (Ω m) T temperature (K) t time (min) x location position (m) Subscripts i inside o outside Pc pseudo critical s stable condition v vibration w wall

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“…Physical parameters of colloids, including phase stability, can be examined with the use of an optical sensing method, such as UV-VIS, spectroscopy, turbidimetry, and dynamic light scattering [ 60 , 61 , 62 , 63 ]. Besides the physical phase of colloid stability, the thermo-stability and photostability of diesel fuel are under investigation [ 64 ]. The examination method of photostability is at the proposition phase [ 65 ].…”

Section: Introductionmentioning

confidence: 99%

Automotive Diesel Fuel Internal Stability Testing with the Use of UV and Temperature as Degradation Factors

2022

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Diesel fuel stability can be considered from many points of view, of which the two considered most important are stability in contact with the environment and internal stability. Fuel stability in touch with the environment is often defined as oxidation stability, of which measurement procedures are well developed. The presented paper shows that fuel’s internal stability can also be important. The internal stability of diesel fuel with the local use of thermal and ultraviolet radiation (UV) as degradation factors and fluorescence signals as a probe is presented in this paper. We show that the internal degradation of fuel with temperature use differs from that with UV and simultaneous both factors use. Our study shows that using temperature as a degradation factor introduces significant fluorescence fading. Moreover, the fluorescence signal restores significantly later than the sample stabilizes at room temperature. The novelty proposed based on examination is hybrid degradation and an examination cycle that enables the simultaneous use of degradation factors and fluorescence reading. For this purpose, a dedicated measurement setup of signal control and processing was constructed and programmed. The measurement procedure of the data series for specific wavelength enables calculation of signal shifts that allow the internal stability classification of diesel fuel samples in less than 30 min with the cost of a single disposable capillary probe and one polymer plug. Premium and regular fuel examination results show that internal fuel stability can be related to polycyclic aromatic hydrocarbons (PAH) concentrations and can be modified with dedicated additives.

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Thermal stability and decomposition of diesel fuel under subcritical and supercritical conditions

Cited by 25 publications

References 24 publications

Transition of diesel spray to a supercritical state under engine conditions

Transition of diesel spray to a supercritical state under engine conditions

Thermal and Element Analyses for Supercritical RP-3 Surface Coke Deposition under Stable and Vibration Conditions

Automotive Diesel Fuel Internal Stability Testing with the Use of UV and Temperature as Degradation Factors

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