# Notas de Aula Fenômenos de Transporte Aulas 1-6

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•Thermal equilibrium --the temperature does not change with time not change with time does not change with time unchanging with time (i.e., same liquid/gas or liquid/solid composition)

State State

•The stateof a system is defined by the values of its properties.

State and Equilibrium State and Equilibrium

•Thermodynamics deals with equilibrium states;

* A system is in thermodynamic equilibrium if it maintains thermal, mechanical, phase,and chemical equilibrium

Thermal Equilibrium Thermal Equilibrium same temperature T and no heat transfer can occur.

Zero Zero th th

Law of Law of

Thermodynamics Thermodynamics

•Two bodies are in thermal equilibrium if both have the same temperature readingeven if they are not in contact.

Thermometer

State Principle or State Principle or

State Postulate State Postulate

•Text says,“The state of a simple compressible system is completely given by two independent, intensive properties.”

•Properties are independent if one can be constant while the other varies.

Simple system Simple system

•A simple systemis defined as one for which only onequasiequilibriumwork mode applies.

•Simple compressible systems •Simple elastic systems

•Simple magnetic systems •Simple electrostatic systems, etc.

State Postulate State Postulate

•The thermodynamic state of a simple compressible systemis completely specified by twoindependent intensive properties.

vPTT

Process/Path Process/Path

•Change in state of a system from one equilibrium state to another.

Process Property held constant isobaric pressure isothermal temperature isochoric volume isentropic entropy (see Chapter 6)

Example: Constant Pressure Example: Constant Pressure

Process Process

System Boundary

Vapour

Heat and WorkHeat and Work Heat and Work

•If the ENERGY transfer across the boundaries of a system is due to a temperature difference,it is heat ;otherwise, it is work.

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