scholarly journals Van der Waals-like State Equation for Atmosphere

2020 ◽  
Vol 43 (2) ◽  
Author(s):  
Deusdedit Monteiro Medeiros ◽  
Isamara De Mendonça Silva ◽  
Douglas Do Nascimento Silva ◽  
David Mendes
Keyword(s):  
Van Der Waals ◽  
Potential Temperature ◽  
Intermolecular Forces ◽  
State Equation ◽  
Ideal Gas ◽  
Alternative Form ◽  
Van Der Waals Equation ◽  
Atmospheric Thermodynamics ◽  
Order Of Magnitude ◽  
Virtual Temperature

In this paper, we first analyze the atmosphere as a gas mixture per unit mass, which is governed by Van der Waals equation, considering the main components of the air and their respective critical properties (critical temperature TC and critical pressure pC ). After adjusting the corresponding constants and calling them I and D, we find Van der Waals state equation for the atmosphere in this context. Next, we analyze the order of magnitude of the terms in that equation and propose a Van der Waals-like form state equation depending only on D, which we call WD state equation. Additionally, we consider a physical approach for Van der Waals equation for the atmosphere, studying the pressure terms concerning intermolecular forces of repulsion and attraction in the air, and once again we find the previous WD state equation. With this new proposal, we verify that the potential temperature and the equivalent potential temperature hold for the same expressions as those set forth in atmospheric thermodynamics under the analysis of the ideal gas law. However, we discover corrections that depend on D in both the alternative form of the first law of thermodynamics and the virtual temperature.

Supercritical Fluid of Carbon Dioxide and Carbon Nanotubes

2013 ◽  
pp. 198-201
Keyword(s):  
Carbon Dioxide ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Gas Phase ◽  
Supercritical Fluid ◽  
Van Der Waals ◽  
Ideal Gas ◽  
Test Tube ◽  
Van Der Waals Equation ◽  
Ideal Gas Law

In this exercise students will learn to use a carbon nanotube as gas phase test tube, to study the transition from a gas to a supercritical fluid for CO2. They will also learn to compare the Ideal Gas Law to the van der Waals equation.

Model and Simulaiton of Air Spring Stiffness Characteristics Based on van der Waals Equation

2013 ◽  
Vol 779-780 ◽  
pp. 380-383
Author(s):  
Li Qin Sun ◽  
Zhong Xing Li ◽  
Xu Feng Shen ◽  
Hua Wei Zhao
Keyword(s):  
Van Der Waals ◽  
Ideal Gas ◽  
Factor H ◽  
Spring Stiffness ◽  
Air Spring ◽  
Real Gas ◽  
Van Der Waals Equation ◽  
Working Temperature ◽  
Stiffness Model ◽  
Stiffness Characteristics

Air spring gas is generally regarded as an ideal gas in analysis , but this is not consistent with the actual work . Considerring influence of non-ideal gas to air spring stiffness ,and based on van der Waals equation which is closed to the real gas equation, stiffness characteristics model of air spring and air spring with auxiliary chamber are re-derived and established. Influence of non ideal gas correction factor H to air spring stiffness is analysed within the range of pressure 0.2MPa to 5 MPa and working temperature -50 °C to 50°C,and results show that , there are big errors in air spring stiffness model in the conditon of low temperature and high pressure based on ideal gas equation, and range of application of the stiffness model is expanded when H is introduced and amended.

scholarly journals An Analytical Investigation of Natural Convection of a Van Der Waals Gas over a Vertical Plate

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 121
Author(s):  
Andriy A. Avramenko ◽  
Igor V. Shevchuk ◽  
Margarita M. Kovetskaya
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Vertical Plate ◽  
Van Der Waals ◽  
Nonlinear Effects ◽  
Analytical Investigation ◽  
Ideal Gas ◽  
Van Der Waals Gas ◽  
Van Der Waals Equation ◽  
Nusselt Numbers

The study focused on a theoretical study of natural convection in a van der Waals gas near a vertical plate. A novel simplified form of the van der Waals equation derived in the study enabled analytical modeling of fluid flow and heat transfer. Analytical solutions were obtained for the velocity and temperature profiles, as well as the Nusselt numbers. It was revealed that nonlinear effects considered by the van der Waals equation of state contribute to acceleration or deceleration of the flow. This caused respective enhancement or deterioration of heat transfer. Results for a van der Waals gas were compared with respective computations using an ideal gas model. Limits of the applicability of the simplified van der Waals equations were pinpointed.

scholarly journals Limiting temperature of pion gas with the van der Waals equation of state

2016 ◽  
Vol 43 (9) ◽  
pp. 095105 ◽  
Author(s):  
R V Poberezhnyuk ◽  
V Vovchenko ◽  
D V Anchishkin ◽  
M I Gorenstein
Keyword(s):  
Equation Of State ◽  
Van Der Waals ◽  
Van Der Waals Equation

scholarly journals The van der Waals equation: analytical and approximate solutions

2007 ◽  
Vol 43 (4) ◽  
pp. 1437-1457 ◽  
Author(s):  
Mario N. Berberan-Santos ◽  
Evgeny N. Bodunov ◽  
Lionello Pogliani
Keyword(s):  
Van Der Waals ◽  
Approximate Solutions ◽  
Van Der Waals Equation

From Van der Waals' equation to the scaling laws

Physica ◽  
1974 ◽  
Vol 73 (1) ◽  
pp. 73-106 ◽  
Author(s):  
J.M.H. Levelt Sengers
Keyword(s):  
Scaling Laws ◽  
Van Der Waals ◽  
Van Der Waals Equation

scholarly journals Nonlinear Processes in Safety Systems for Substances with Parameters Close to a Critical State

2021 ◽  
Vol 17 (1) ◽  
pp. 119-138
Author(s):  
M. R. Koroleva ◽  
◽  
O. V. Mishchenkova ◽  
V. A. Tenenev ◽  
T. Raeder ◽  
...  
Keyword(s):  
Equation Of State ◽  
Critical State ◽  
Stokes Equations ◽  
Safety Valve ◽  
Van Der Waals ◽  
Local Approximation ◽  
Critical Conditions ◽  
Nonlinear Processes ◽  
Real Gas ◽  
Van Der Waals Equation

The paper presents a modification of the digital method by S. K. Godunov for calculating real gas flows under conditions close to a critical state. The method is generalized to the case of the Van der Waals equation of state using the local approximation algorithm. Test calculations of flows in a shock tube have shown the validity of this approach for the mathematical description of gas-dynamic processes in real gases with shock waves and contact discontinuity both in areas with classical and nonclassical behavior patterns. The modified digital scheme by Godunov with local approximation of the Van der Waals equation by a two-term equation of state was used for simulating a spatial flow of real gas based on Navier – Stokes equations in the area of a complex shape, which is characteristic of the internal space of a safety valve. We have demonstrated that, under near-critical conditions, areas of nonclassical gas behavior may appear, which affects the nature of flows. We have studied nonlinear processes in a safety valve arising from the movement of the shut-off element, which are also determined by the device design features and the gas flow conditions.

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