A phenomenological correction to an equation of state for the critical region

Chou, Grace F.; Prausnitz, John M.

doi:10.1002/aic.690350909

Cited by 86 publications

(28 citation statements)

References 29 publications

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“…Enfin, d'autres auteurs comme Mathias et al (1989) ou Chou et Prausnitz (1989) ont proposŽ des mŽthodes de translation de volume fonction de la tempŽrature et de la densitŽ. Cette approche fait perdre ˆ l'Žquation d'Žtat son caract•re cubique ˆ cause de la dŽpendance en densitŽ (le volume n'est plus obtenu par une Žquation polynomiale de degrŽ 3).…”

Section: Les Mƒthodes De Translation De Volumeunclassified

Prédiction des propriétés volumétriques des hydrocarbures par une translation de volume améliorée

Ungerer

Batut

1997

Rev. Inst. Fr. Pét.

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Ë la suite des travaux de PŽneloux et al. (1982), plusieurs auteurs (Soreide, 1989 ;Magoulas et Tassios, 1990 ;Coniglio, 1993) Ë l'exception de la rŽgion pŽri-critique, la prŽcision reste bonne ˆ basse pression. La nouvelle mŽthode de translation de volume permet de supprimer les incohŽrences des mŽthodes existantes et, ˆ l'opposŽ de cellesci, s'av•re cohŽrente avec les r•gles de mŽlange quand l'on regroupe plusieurs constituants en un pseudo-constituant. Son application aux mŽlanges pŽtroliers appara"t donc prometteuse. (Soreide, 1989;Magoulas and Tassios, 1990;Coniglio, 1993). The present work aims at improving these predictions, particularly in the case of oil and gas reservoirs (temperature up to 200¡C and pressures as high as 120 MPa), using the Peng-Robinson equation of state. As volume translation methods sometimes show inconsistencies at high pressure (e.g., negative thermal expansion coefficient) we had to develop an original expression. For this purpose, we used high pressure density measurements instead of saturated liquid densities. Several pure hydrocarbons from various families were considered: C 6 to C 40 n-alkanes, cyclohexane, C 6 to C 12 monoaromatics.Within a good approximation, the volume translation c is thus shown to follow a linear dependancy with temperature and with molecular weight:where c is in cm 3 /mol, T in K and MW in g/mol.When this expression is used, average errors at high pressure are low (less than 3% for the C 6 to C 13 hydrocarbons investigated With the exception of the near-critical region, the method is still accurate at low pressure. The method does not display the inconsistencies of previous methods, and it is also shown to be consistent with mixing rules when several pure components are lumped into a single pseudo-component. As a consequence, its application to real fluids looks promising. PREDICCION DE LAS PROPIEDADES VOLUMƒTRICAS DE LOS HIDROCARBUROS POR UNA TRANSLACIîN DE VOLUMEN MEJORADAA ra'z de los trabajos de PŽneloux y sus colaboradores (1982), diversos autores (Soreide, 1989 ; Magoulas y Tassios, 1990 y Coniglio, 1993, propusieron mŽtodos de translaci-n de volumen para calcular de mejor modo los pesos espec'ficos de los l'quidos por medio de ecuaciones de estado. El presente trabajo tiene por prop-sito mejorar estas predicciones, y fundamentalmente, en las condiciones reinantes en los yacimientos petroleros (temperaturas hasta 200 ¡C y presiones que alcanzan los 120 MPa), por implementaci-n de la ecuaci-n de estado de Peng-Robinson. Habida cuenta que los mŽtodos existentes son incoherentes en ciertas condiciones (ej. coeficiente de expansi-n tŽrmica negativo) hemos desarrollado una expresi-n original para la translaci-n de volumen. Con este objeto, hemos utilizado las mediciones de peso espec'fico en alta presi-n, y no los pesos espec'ficos del l'quido en saturaci-n. Se han estudiado as' diversos hidrocarburos de distintas familias : n-alcanos de C 6 a C 40 , ciclohexano, y asimismo, monoarom ‡ticos de C 6 a C 12 . La translaci-n de volumen c obedece, aproxi...

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Section: Les Mƒthodes De Translation De Volumeunclassified

Prédiction des propriétés volumétriques des hydrocarbures par une translation de volume améliorée

Ungerer

Batut

1997

Rev. Inst. Fr. Pét.

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“…The PR EoS is an adequate choice for temperatures above and close to the critical temperature, however, in the transcritical regime considerable deviations from experimental data can be observed [11]. In the present work, we therefore employ the volume-translation method of Abudour et al method of Chou and Prausnitz [15] that considerably improves the accuracy of the density prediction at minimal extra computational cost. The basic principle is to shift the thermodynamic state of the fluid along its volume axis keeping pressure and temperature constant.…”

Section: Real-gas Thermodynamicsmentioning

confidence: 99%

“…These methods have the advantage to improve the predictive quality of cubic EoSs for near-critical conditions without a significant degradation of their good computational performance. In the present work, we employ the volume-translation method of Abudour et al [14] which is based on the work of Chou and Prausnitz [15]. This method has already been used in our previous LES studies of supercritical nitrogen injection [16] as well as of inert coaxial LN 2 /GH 2 injection [17].…”

Section: Introductionmentioning

confidence: 99%

A flamelet model for transcritical LOx/GCH₄flames

Müller

Pfitzner

2017

J. Phys.: Conf. Ser.

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Abstract. This work presents a numerical framework to efficiently simulate methane combustion at supercritical pressures. A LES flamelet approach is adapted to account for real-gas thermodynamics effects which are a prominent feature of flames at near-critical injection conditions. The thermodynamics model is based on the Peng-Robinson equation of state (PR-EoS) in conjunction with a novel volume-translation method to correct deficiencies in the transcritical regime. The resulting formulation is more accurate than standard cubic EoSs without deteriorating their good computational performance. To consistently account for pressure and strain fluctuations in the flamelet model, an additional enthalpy equation is solved along with the transport equations for mixture fraction and mixture fraction variance. The method is validated against available experimental data for a laboratory scale LOx/GCH 4 flame at conditions that resemble those in liquid-propellant rocket engines. The LES result is in good agreement with the measured OH * radiation. IntroductionTodays main stage liquid-propellant rocket engines (LRE) typically operate at supercritical pressures, i.e., at chamber pressures that exceed the critical pressure of the propellants, and at cryogenic injection temperatures. One or both of the propellants are thus injected at near-critical conditions and mixing, ignition and combustion are affected by non-ideal thermodynamic effects. In particular, the thermodynamic-and transport properties, e.g., density, enthalpy, viscosity, are highly non-linear functions of temperature and pressure. Moreover, the experiments of Mayer et al. [1,2] showed that the surface tension between liquid and vapor is diminished at sufficiently high pressures and mixing is characterized by continuous-phase diffusion rather than by two-phase spray atomization. In these diffusion mixing layers, the fluid properties change drastically and the density may vary by two orders of magnitude within a few micrometers.Such configurations pose a serious challenge for numerical as well as for experimental studies. At the same time, their investigation is important to better understand the involved processes and to develop tools that help in the design of LREs, but also of other high pressure combustion devices, such as novel Diesel motors or gas turbines. The topic received considerable attention in the last decade and several valuable experiments were carried out. Thorough overviews are given, for instance, by Oschwald et al. [5] focusing on the Mascotte testing facility. Along with the better understanding that has been generated by the experimental efforts, several groups developed models and numerical tools to perform simulations of near-critical mixing and combustion allowing for a detailed view on the flow. Among the first to conduct large-eddy simulations (LES) of supercritical injection was Oefelein and Yang [6] and later Zong et al. [7] as well as Oefelein [8]. These studies showed that the accurate treatment of thermodynamic non-idealities are ke...

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“…The true critical molar volume is needed for the volume translation method, proposed by Chou and Prausnitz (Chou and Prausnitz, 1989). For the binary system methanen-decane, the Chueh-Prausnitz correlation (Chueh and Prausnitz, 1967) was used.…”

Section: Appendix C Correlation Of the Critical Molar Volume Of A Mumentioning

confidence: 99%

“…In addition to the original RKS equation, a volume translation for this equation of state, proposed by Chou and Prausnitz (Chou and Prausnitz, 1989), was used to correlate drop-out curves for the methane -Kensol-16 system. The unknown true critical volumes of the mixture, which are important input data for the volume translation, were estimated using an empirical method (Appendix C).…”

Section: Multicomponent Systemmentioning

confidence: 99%

Correlation of high‐pressure phase equilibria in the retrograde region with three common equations of state

1991

Self Cite

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Phase equilibria in the retrograde regions were calculated for the methane — n‐decane binary system and for a realistic natural‐gas system (methane ‐ Kensol‐16). Calculations were performed using three equations of state (EOS): Peng‐Robinson, Redlich‐Kwong‐Soave and Perturbed‐Hard‐Chain; calculations were compared to experiment. Liquid‐drop‐out curves and pressure‐temperature diagrams were calculated between 301 and 369 K and pressures to 90 MPa. The binary system was represented best by the Peng‐Robinson EOS. For the natural‐gas system, the Perturbed‐Hard Chain equation yielded the best results, although all equations of state showed appreciable deviations. Good results could only be obtained when binary coefficients were fitted to the experimental retrograde data.

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A phenomenological correction to an equation of state for the critical region

Cited by 86 publications

References 29 publications

Prédiction des propriétés volumétriques des hydrocarbures par une translation de volume améliorée

Prédiction des propriétés volumétriques des hydrocarbures par une translation de volume améliorée

A flamelet model for transcritical LOx/GCH₄flames

Correlation of high‐pressure phase equilibria in the retrograde region with three common equations of state

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A phenomenological correction to an equation of state for the critical region

Cited by 86 publications

References 29 publications

Prédiction des propriétés volumétriques des hydrocarbures par une translation de volume améliorée

Prédiction des propriétés volumétriques des hydrocarbures par une translation de volume améliorée

A flamelet model for transcritical LOx/GCH4flames

Correlation of high‐pressure phase equilibria in the retrograde region with three common equations of state

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A flamelet model for transcritical LOx/GCH₄flames