An approach to get thermodynamic properties from speed of sound

8th International Congress of Engineering Physics

物理学;工业技术

Núñez, M.A.^1 ; Medina, L.A.^1

Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, A. P. 55-534, C.P. 09340, D.F., Mexico^1

关键词: Compression factor;    Dirichlet boundary condition;    Linear ordinary differential equations;    Molar heat capacities;    Nonlinear partial differential equations;    Orders of magnitude;    Perturbation error;    Temperature values;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/792/1/012035/pdf
DOI  :  10.1088/1742-6596/792/1/012035

学科分类：工业工程学

来源: IOP

【 摘 要 】

An approach for estimating thermodynamic properties of gases from the speed of sound u, is proposed. The square u2, the compression factor Z and the molar heat capacity at constant volume CVare connected by two coupled nonlinear partial differential equations. Previous approaches to solving this system differ in the conditions used on the range of temperature values [Tmin,Tmax]. In this work we propose the use of Dirichlet boundary conditions at Tmin, Tmax. The virial series of the compression factor Z = 1+Bρ+Cρ2+... and other properties leads the problem to the solution of a recursive set of linear ordinary differential equations for the B, C. Analytic solutions of the B equation for Argon are used to study the stability of our approach and previous ones under perturbation errors of the input data. The results show that the approach yields B with a relative error bounded basically by that of the boundary values and the error of other approaches can be some orders of magnitude lager.