The generalized engineering Bernoulli equation (GEBE) and the first and second laws of thermodynamics for viscoelastic fluids
| Autor: | Michael E. Mackay, Gianni Astarita |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Physics
Mechanical Engineering media_common.quotation_subject Equations of motion Cauchy distribution Second law of thermodynamics Dissipation Condensed Matter Physics Laws of thermodynamics Euler equations symbols.namesake Bernoulli's principle Classical mechanics Mechanics of Materials symbols General Materials Science First law of thermodynamics media_common |
| Zdroj: | Journal of Rheology. 40:335-346 |
| ISSN: | 1520-8516 0148-6055 |
| DOI: | 10.1122/1.550746 |
| Popis: | In this work we thoroughly explore the meanings of dissipation (sometimes referred to as viscous dissipation) and stress power. To do this we utilize the Cauchy momentum equations and the first and second laws of thermodynamics. First, the generalized engineering Bernoulli equation (GEBE) is derived from the Cauchy momentum equations and it is clearly shown to have nothing to do with a balance of energy. Next, the first law of thermodynamics or energy balance is discussed and a combined equation by subtracting the two is derived which we refer to as the mechanoenergy balance (sometimes referred to as the ‘‘equation of thermal energy’’). The fact that a difference exists further reinforces that the GEBE is not related to a balance of energy. Finally, the second law of thermodynamics is presented and the concept of dissipation introduced. An example is presented to demonstrate the utility of these equations which will hopefully eliminate some confusion in the literature. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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