scholarly journals Isobaric and Isochoric Heat Capacities of Imidazolium-Based and Pyrrolidinium-Based Ionic Liquids as a Function of Temperature: Modeling of Isobaric Heat Capacity

2017 ◽  
Vol 56 (9) ◽  
pp. 2592-2606 ◽  
Author(s):  
Edward Zorębski ◽  
Michał Zorębski ◽  
Marzena Dzida ◽  
Peter Goodrich ◽  
Johan Jacquemin
Keyword(s):  
Heat Capacity ◽  
Ionic Liquids ◽  
Heat Capacities ◽  
Isobaric Heat Capacity ◽  
Temperature Modeling

scholarly journals АНАЛИТИЧЕСКОЕ ОПРЕДЕЛЕНИЕ ИСТИННОЙ УДЕЛЬНОЙ ИЗОБАРНОЙ ТЕПЛОЁМКОСТИ КОМПОНЕНТ ВОЗДУХА И ПРОДУКТОВ СГОРАНИЯ С УЧЁТОМ ВЛИЯНИЯ ТЕМПЕРАТУРЫ И ДАВЛЕНИЯ И ЭФФЕКТА ТЕРМИЧЕСКОЙ ДИССОЦИАЦИИ

2019 ◽  
pp. 4-17
Author(s):  
Майя Владимировна Амброжевич ◽  
Михаил Анатольевич Шевченко
Keyword(s):  
Heat Capacity ◽  
Gas Turbine ◽  
Pressure Ratio ◽  
Thermal Dissociation ◽  
Combustion Products ◽  
Heat Capacities ◽  
Isobaric Heat Capacity ◽  
Working Fluid ◽  
Gas Temperature ◽  
Temperature And Pressure

The basic thermophysical parameter of the working fluid of all thermal machines without exception is isobaric heat capacity (specific heat at constant pressure). Traditionally, in engineering calculations of isobaric heat capacity are determined as a tabular value for average heat capacities, or approximated with a square parabola within a given temperature range. Isobaric heat capacity is a function of temperature only. At the current level of GTE development, when the overall compressor pressure ratio is already up to 50 and the tendency of its increase remains it is unacceptable to neglect the pressure. However, the turbine inlet gas temperature also rises that will inevitably lead to the effect of thermal dissociation in the combustion products of the gas turbine engine. The studies of the thermal dissociation effect influence on the parameters of the working process of advanced GTE show that this ignoring leads to computational errors. At the present time, there are mathematical models that allow calculating the isobaric heat capacity as a function of temperature and pressure (taking into account the effect of thermal dissociation) but they are laborious, which is not always practical when estimate calculations performing and program algorithms writing. Consequently, the authors posed the problem of obtaining of simple analytic relationships that make it possible to calculate the isobaric heat capacity as a function of temperature and pressure (taking into account the effect of thermal dissociation). Based on the tabular data for the main components of the gas turbine combustion products within a given range of pressures and temperatures (nitrogen: p = 1 ... 200 bar, T = 150 ... 2870 K, oxygen: p = 1 ... 200 bar, T = 210 ... 2870 K, argon: p = 1 ... 200 bar, T = 190 ... 1300 K, the water vapor: p = 0.1 ... 200 bar, T = 640 ... 1250 K and p = 0.1 ... 400 bar and T = 1250 ... 3200 K, carbon dioxide: p = 1 ... 200 bar, T = 390 ... 2600 K), analytical dependencies were obtained for the calculation of isobaric heat capacities as functions of temperature and pressure taking into account the effect of thermal dissociation. The results of the calculations were compared with tabulated experimental data.

scholarly journals EQUATIONS OF AVERAGE ISOBARIC HEAT CAPACITY OF AIR AND COMBUSTION GASES WITH INFLUENCE OF PRESSURE AND EFFECT OF THERMAL DISSOCIATION

2019 ◽  
pp. 18-29
Author(s):  
Maya Vladimirovna Ambrozhevich ◽  
Mikhail Anatol'evich Shevchenko
Keyword(s):  
Heat Capacity ◽  
Thermophysical Properties ◽  
Thermal Dissociation ◽  
Heat Capacities ◽  
Isobaric Heat Capacity ◽  
Information Storage ◽  
Working Fluid ◽  
Saturation Curve ◽  
Functional Dependencies ◽  
Temperature And Pressure

All properties of thermomechanical systems working substance are two-parameter that is determined by two parameters, the most often they are temperature and pressure which are easily measured by experiment. Representing the isobaric heat capacity as a function of temperature cp = f(T) become a thing of the past. Analytical and tabular ways are used to represent dependencies as a function of temperature and pressure. The tabular method is convenient for single calculations, but the analytical one is more convenient for a series of calculations. The advantages of an analytical description in comparison with a tabular one are obvious, namely, compactness of information storage without reference to node points, the ability to integrate and differentiate, dependencies can be embedded directly in the program body and don’t require special subroutines to access to the tables. Developers of the programs for calculating thermophysical properties, as a rule, use functional dependencies which may have a different appearance for temperature and pressure intervals of the same substance. This is explained by the fact that in the region close to the saturation curve, there is a steep change in all the thermophysical properties of substances including the isobaric heat capacity. In thermogasdynamic calculations of heat machines, the main physical parameter of the working fluid is its heat capacity, both true and average. The article presents the analytical dependencies of the average specific isobaric heat capacities of the main components of air and combustion products of hydrocarbon fuels which are united throughout the specified range of pressures and temperatures (nitrogen: p = 1 ... 200 bar, T = 150 ... 2870 K, oxygen: p = 1 ... 200 bar, T = 210 ... 2870 K, argon: p = 1 ... 200 bar, T = 190 ... 1300 K, the water vapor: p = 0,1 ... 200 bar, T = 700 ... 2600 K, carbon dioxide: p = 1 ... 200 bar, T = 390 ... 2600 K). The analytical dependencies were derived on the basis of previously obtained analytical expressions for the specific isobaric heat capacities of these gases. The average specific isobaric heat capacities of gases are also functions of temperature and pressure cp = f(T, P) and take into account the effect of thermal dissociation. Formulas for average specific isobaric heat capacities are obtained by integrating expressions for specific isobaric heat capacities. Verification of the obtained dependencies for different temperature ranges was done.

scholarly journals Thermal Analysis of Binary Mixtures of Imidazolium, Pyridinium, Pyrrolidinium, and Piperidinium Ionic Liquids

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6383
Author(s):  
Elena Gómez ◽  
Pedro Velho ◽  
Ángeles Domínguez ◽  
Eugénia A. Macedo
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Ionic Liquids ◽  
Thermal Behavior ◽  
Binary Mixtures ◽  
Heat Capacities ◽  
Viable Alternative ◽  
Transition Temperatures ◽  
Scanning Calorimetry

Ionic liquids (ILs) are being widely studied due to their unique properties, which make them potential candidates for conventional solvents. To study whether binary mixtures of pure ionic liquids provide a viable alternative to pure ionic liquids for different applications, in this work, the thermal analysis and molar heat capacities of five equimolar binary mixtures of ionic liquids based on imidazolium, pyridinium, pyrrolidinium, and piperidinium cations with dicyanamide, trifluoromethanesulfonate, and bis(trifluoromethylsulfonyl)imide anions have been performed. Furthermore, two pure ionic liquids based on piperidinium cation have been thermally characterized and the heat capacity of one of them has been measured. The determination and evaluation of both the transition temperatures and the molar heat capacities was carried out using differential scanning calorimetry (DSC). It was observed that the thermal behavior of the mixtures was completely different than the thermal behavior of the pure ionic liquids present, while the molar heat capacities of the binary mixtures were very similar to the value of the average of molar heat capacities of the two pure ionic liquids.

Development of the room temperature protocol based on room temperature ionic liquids and surfactant ionic liquids for the synthesis of derivatives of 2-amino-thiazoles and thermo-physical analysis of the synthesized derivatives using TGA-DSC.

2020 ◽  
Vol 10 ◽  
Author(s):  
Chandrakant Sarode ◽  
Sachin Yeole ◽  
Ganesh Chaudhari ◽  
Govinda Waghulde ◽  
Gaurav Gupta
Keyword(s):  
Thermal Analysis ◽  
Heat Capacity ◽  
Ionic Liquids ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Room Temperature ◽  
Heat Capacity Data ◽  
General Strategy ◽  
Capacity Data ◽  
Derivatives Of

Aims: To develop an efficient protocol, which involves an elegant exploration of the catalytic potential of both the room temperature and surfactant ionic liquids towards the synthesis of biologically important derivatives of 2-aminothiazole. Objective: Specific heat capacity data as a function of temperature for the synthesized 2- aminothiazole derivatives has been advanced by exploring their thermal profiles. Method: The thermal gravimetry analysis and differential scanning calorimetry techniques are used systematically. Results: The present strategy could prove to be a useful general strategy for researchers working in the field of surfactants and surfactant based ionic liquids towards their exploration in organic synthesis. In addition to that, effect of electronic parameters on the melting temperature of the corresponding 2-aminothiazole has been demonstrated with the help of thermal analysis. Specific heat capacity data as a function of temperature for the synthesized 2-aminothiazole derivatives has also been reported. Conclusion: Melting behavior of the synthesized 2-aminothiazole derivatives is to be described on the basis of electronic effects with the help of thermal analysis. Additionally, the specific heat capacity data can be helpful to the chemists, those are engaged in chemical modelling as well as docking studies. Furthermore, the data also helps to determine valuable thermodynamic parameters such as entropy and enthalpy.

Heat capacities and enthalpies of fusion and transformation for solvates of some salts with dimethyl sulfoxide and dimethylformamide

1988 ◽  
Vol 53 (12) ◽  
pp. 3072-3079
Author(s):  
Mojmír Skokánek ◽  
Ivo Sláma
Keyword(s):  
Heat Capacity ◽  
Phase Transformation ◽  
Phase Transformations ◽  
Dimethyl Sulfoxide ◽  
Liquidus Temperature ◽  
Molar Heat Capacity ◽  
Solid Phase ◽  
Zinc Nitrate ◽  
Heat Capacities ◽  
Liquid Phases

Molar heat capacities and molar enthalpies of fusion of the solvates Zn(NO3)2 . 2·24 DMSO, Zn(NO3)2 . 8·11 DMSO, Zn(NO3)2 . 6 DMSO, NaNO3 . 2·85 DMSO, and AgNO3 . DMF, where DMSO is dimethyl sulfoxide and DMF is dimethylformamide, have been determined over the temperature range 240 to 400 K. Endothermic peaks found for the zinc nitrate solvates below the liquidus temperature have been ascribed to solid phase transformations. The molar enthalpies of the solid phase transformations are close to 5 kJ mol-1 for all zinc nitrate solvates investigated. The dependence of the molar heat capacity on the temperature outside the phase transformation region can be described by a linear equation for both the solid and liquid phases.

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