scholarly journals Validation of the Jarzynski relation for a system with strong thermal coupling: An isothermal ideal gas model

2006 ◽  
Vol 74 (6) ◽  
Author(s):  
A. Baule ◽  
R. M. L. Evans ◽  
P. D. Olmsted
Keyword(s):  
Ideal Gas ◽  
Thermal Coupling ◽  
Ideal Gas Model

scholarly journals Thermodynamic modeling of the Al-K system

2009 ◽  
Vol 45 (1) ◽  
pp. 89-93 ◽  
Author(s):  
Y. Du ◽  
X. Yuan ◽  
W. Sun ◽  
B. Hu
Keyword(s):  
Phase Diagram ◽  
Gas Phase ◽  
Thermodynamic Modeling ◽  
Phase Diagram Data ◽  
Ideal Gas ◽  
Monotectic Reaction ◽  
Present Calculation ◽  
Experimental Phase ◽  
Experimental Phase Diagram ◽  
Ideal Gas Model

A thermodynamic modeling for the Al-K system is conducted. The thermodynamic parameters for liquid, (Al), and (K) are evaluated by using the experimental phase diagram data from the literature. The gas phase is described with an ideal gas model. The calculated Al-K phase diagram agrees well with the experimental data. In particular, the observed monotectic reaction is well described by the present calculation.

scholarly journals Mathematical Model of Small-Volume Air Vessel Based on Real Gas Equation

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 530 ◽  
Author(s):  
Weixiang Ni ◽  
Jian Zhang ◽  
Lin Shi ◽  
Tengyue Wang ◽  
Xiaoying Zhang ◽  
...  
Keyword(s):  
Water Depth ◽  
Small Volume ◽  
Pressure Oscillation ◽  
State Equation ◽  
Ideal Gas ◽  
Pipeline System ◽  
Real Gas ◽  
Polytropic Equation ◽  
Real Gas Equations ◽  
Ideal Gas Model

The gas characteristics of an air vessel is one of the key parameters that determines the protective effect on water hammer pressure. Because of the limitation of the ideal gas state equation applied for a small-volume vessel, the Van der Waals (VDW) equation and Redlich–Kwong (R–K) equation are proposed to numerically simulate the pressure oscillation. The R–K polytropic equation is derived under the assumption that the volume occupied by the air molecules themselves could be ignored. The effects of cohesion pressure under real gas equations are analyzed by using the method of characteristics under different vessel diameters. The results show that cohesion pressure has a significant effect on the small volume vessel. During the first phase of the transient period, the minimum pressure and water depth calculated by a real gas model are obviously lower than that calculated by an ideal gas model. Because VDW cohesion pressure has a stronger influence on the air vessel pressure compared to R–K air cohesion pressure, the amplitude of head oscillation in the vessel calculated by the R–K equation becomes larger. The numerical results of real gas equations can provide a higher safe-depth margin of the water depth required in the small-volume vessel, resulting in the safe operation of the practical pumping pipeline system.

scholarly journals OPAL Equation of State Tables

1995 ◽  
Vol 10 ◽  
pp. 331-332
Author(s):  
F.J. Rogers
Keyword(s):  
Equation Of State ◽  
Seismic Data ◽  
Bound States ◽  
Ideal Gas ◽  
Many Body ◽  
Astrophysical Plasmas ◽  
Wide Range ◽  
Hydrogen Mass ◽  
Ideal Gas Model

The equation of state of astrophysical plasmas is, for a wide range of stars, nearly ideal with only small non-ideal Coulomb corrections. Calculating the equation of state of an ionizing plasma from a ground state ion, ideal gas model is easy, whereas, fundamental methods to include the small Coulomb corrections are difficult. Attempts to include excited bound states are also complicated by many-body effects that weaken and broaden these states. Nevertheless, the high quality of current observations, particularly seismic data, dictates that the best possible models should be used. The equation of state used in the OPAL opacity tables is based on many-body quantum statistical methods (Rogers, 1994; 1986; 1981) and is suitable for the modeling of seismic data. Extensive tables of the OPAL equation of state are now available. These tables cover the temperature range 5 × 10−3 to 1 × 108 K, the density range 10-14 to 105 g/cm3, the hydrogen mass fraction (X) range 0.0 to 0.8, and the metallicity (Z) range 0.0 to 0.04.

In-Cylinder Temperature Measurements in a 55-cm3 Two-Stroke Engine Via Tunable Laser Absorption Spectroscopy

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Joseph K. Ausserer ◽  
Marc D. Polanka ◽  
Matthew J. Deutsch ◽  
Jacob A. Baranski ◽  
Keith D. Rein
Keyword(s):  
Absorption Spectroscopy ◽  
Ideal Gas ◽  
Operating Conditions ◽  
Temperature Measurements ◽  
Cylinder Pressure ◽  
Laser Absorption Spectroscopy ◽  
Laser Absorption ◽  
Ideal Gas Model ◽  
Stroke Engine ◽  
The Ideal

Abstract In-cylinder temperature is a critical quantity for modeling and understanding combustion dynamics in internal combustion engines (ICEs). It is difficult to measure in small, two-stroke engines due to high operational speeds and limited space to install instrumentation. Optical access was established in a 55-cm3 displacement two-stroke engine using M4 bolts as carriers for sapphire rods to establish a 1.5-mm diameter optical path through the combustion chamber. Temperature laser absorption spectroscopy was successfully used to measure time varying in-cylinder temperature clocked to the piston position with a resolution of 3.6 crank angle degrees (CAD) at 6000 rpm. The resulting temperature profiles clearly showed the traverse of the flame front and were qualitatively consistent with in-cylinder pressure, engine speed, and delivery ratio. The temperature measurements were compared to aggregate in-cylinder temperatures calculated using the ideal gas model using measured in-cylinder pressure and trapped mass calculated at exact port closure as inputs. The calculation was sensitive to the trapped mass determination, and the results show that using the ideal gas model for in-cylinder temperature calculations in heat flux models may fail to capture trends in actual in-cylinder temperature with changing engine operating conditions.

scholarly journals Equation of State of Stellar Plasmas

1994 ◽  
Vol 147 ◽  
pp. 16-42
Author(s):  
Forrest J. Rogers
Keyword(s):  
Equation Of State ◽  
Bound States ◽  
Expansion Method ◽  
Ideal Gas ◽  
Many Body ◽  
Astrophysical Plasmas ◽  
Wide Range ◽  
Quantum Statistical ◽  
Ideal Gas Model

AbstractThe equation of state (EOS) of astrophysical plasmas is, for a wide range of stars, nearly ideal; with only small non-ideal Coulomb corrections. Calculating the EOS of an ionizing plasma from a ground state ion, ideal gas model is easy, whereas, fundamental methods to include the small Coulomb corrections are difficult. Attempts to include excited bound states are also complicated by plasma screening and microfield phenomena that weaken and broaden these states. Nevertheless, the high quality of current observational data, particularly seismic, dictates that the best possible models should be used. The present article discusses these issues and describes how they are resolved by fundamental many-body quantum statistical methods. Particular emphasis is placed on the activity expansion method that is the basis of the OPAL opacity code. Some comparisons with standard methods are given.

scholarly journals A Numerical Study on the Supersonic Steam Ejector Use in Steam Turbine System

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Lin Cai ◽  
Miao He
Keyword(s):  
Steam Turbine ◽  
Numerical Study ◽  
Fluid Pressure ◽  
Ideal Gas ◽  
Entrainment Ratio ◽  
Real Gas ◽  
Steam Ejector ◽  
Mixing Chamber ◽  
Cfd Method ◽  
Ideal Gas Model

Supersonic steam ejector is widely used in steam energy systems such as refrigeration, wood drying equipment, papermaking machine, and steam turbine. In this paper the Computational Fluids Dynamics (CFD) method was employed to simulate a supersonic steam ejector, SST k-w turbulence model was adopted, and both real gas model and ideal gas model for fluid property were considered and compared. The mixing chamber angle, throat length, and nozzle exit position (NXP) primary pressure and temperature effects on entrainment ratio were investigated. The results show that performance of the ejector is underestimated using ideal gas model, and the entrainment ratio is 20%–40% lower than that when using real gas model. There is an optimum mixing chamber angel and NXP makes the entrainment ratio achieve its maximum; as throat length is decreased within a range, the entrainment ratio remains unchanged. Primary fluid pressure has a critical value, and the entrainment ratio reaches its peak at working critical pressure; when working steam superheat degree increases, the entrainment ratio is increased.

scholarly journals Development of Modified Incompressible Ideal Gas Model for Natural Draft Cooling Tower Flow Simulation

2018 ◽  
Vol 180 ◽  
pp. 02037
Author(s):  
Tomáš Hyhlík
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Cooling Tower ◽  
Flow Simulation ◽  
Ideal Gas ◽  
Specific Humidity ◽  
Boussinesq Model ◽  
Natural Draft ◽  
Ideal Gas Model

The article deals with the development of incompressible ideal gas like model, which can be used as a part of mathematical model describing natural draft wet-cooling tower flow, heat and mass transfer. It is shown, based on the results of a complex mathematical model of natural draft wet-cooling tower flow, that behaviour of pressure, temperature and density is very similar to the case of hydrostatics of moist air, where heat and mass transfer in the fill zone must be taken into account. The behaviour inside the cooling tower is documented using density, pressure and temperature distributions. The proposed equation for the density is based on the same idea like the incompressible ideal gas model, which is only dependent on temperature, specific humidity and in this case on elevation. It is shown that normalized density difference of the density based on proposed model and density based on the nonsimplified model is in the order of 10-4. The classical incompressible ideal gas model, Boussinesq model and generalised Boussinesq model are also tested. These models show deviation in percentages.

Optimising an Intercooled Compressor for an Ideal Gas Model

2003 ◽  
Vol 31 (3) ◽  
pp. 189-200 ◽  
Author(s):  
Jeffery D. Lewins
Keyword(s):  
Equation Of State ◽  
Specific Heat ◽  
Ideal Gas ◽  
Heat Capacities ◽  
Perfect Gas ◽  
Temperature Dependent ◽  
Specific Heat Capacities ◽  
Ideal Gas Model

Many of the conventional results obtained when optimising the performance of an intercooler during compression using a perfect gas model can be obtained when the restrictions of the model are relaxed to an ideal gas. That is, we now have temperature-dependent specific heat capacities but retain the equation of state pV = RT. This note illustrates the theme.

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