Lecture 1 Flashcards
can be defined as the
science of energy.
Thermodynamics
can be viewed as the ability to
cause changes
Energy
during an interaction, energy
can change from one form to
another but the total amount of
energy remains constant. That
is, energy cannot be created
or destroyed.
Conservation of Energy
Principle
asserts that energy has quality as well as
quantity, and actual processes occur in
the direction of decreasing quality of
energy.
second law of thermodynamics
study of thermodynamics that* does not require a
knowledge* of the behavior of individual
particles
classical thermodynamics
based on the average behavior of large groups of
individual particles
statistical thermodynamics
Any physical quantity can be
characterized by ____________
dimensions
The magnitudes assigned to the
dimensions are called __________
units
basic dimensions such as mass m,
length L, time t, and temperature T
primary or fundamental dimensions
expressed in terms of the primary dimensions ex. velocity, energy, volume
secondary dimensions or derived
dimensions
which is also known as the United States Customary System (USCS)
English system
(from Le Système International d’
Unités) also known as the International
System
metric SI
The unit for time rate of energy is joule per second (J/s), which is called a
watt (W).
In the case of work, the time rate
of energy is called
power
In engineering, all equations must be _________________. That is, every term in an equation must have the same unit. If, at some stage of an analysis, we find ourselves in a position to add two quantities that have different units, it is a clear indication that we have made an error at an earlier stage
Dimensional Homogeneity
is defined as a quantity of matter or a region in space chosen for study.
A system
The mass or region outside the system is
called the
surroundings
The real or imaginary surface that separates the system from its surroundings is called the
boundary
(also known as a control mass or just system when the context makes it clear) consists of a fixed amount
of mass, and no mass can cross its boundary
A closed system
as it is often called, is a properly selected
region in space. It usually encloses a device that involves mass flow such as a compressor, turbine,
or nozzle.
control volume
as a special case, even energy is not
allowed to cross the boundary, that
system is called an
isolated system.
Any characteristic of a system Pressure P, temperature T, volume V, mass
Property
those that are independent of the mass of the* system*
Intensive properties
values depend on the size or* extent of the
system*
Extensive properties
extensive properties per unit mass
Specific Properties
weight of a unit volume of a substance
specific weight
condition of the system At a given state, all the properties of a system have* fixed values*. If the value of even one property changes, the state will change
to a different one.
state
the temperature is the same throughout the entire
system
Thermal equilibrium
related to pressure; no change in pressure at any
point of the system with time
Mechanical equilibrium
when the mass of each phase reaches an equilibrium level and stays there
phase equilibrium
chemical composition does not change with time,
that is, no chemical reactions occur
chemical equilibrium
The state of a simple compressible
system is completely specified by two
independent, intensive properties.
The State Postulate
Any change that a system
undergoes from one equilibrium state to
another
Process
series of states through which a system passes during a process
path of the process
a process proceeds in such a manner
that the system remains infinitesimally
close to an equilibrium state at all times
(quasi-equilibrium)
used to designate a process for which a particular property remains constant
iso
example, is a process during which the
temperature T remains constant
isothermal process
is a process during which the pressure P
remains constant
isobaric process
during which the specific
volume v remains constant
isochoric (or isometric) process
implies no change with time
steady
opposite of
steady
unsteady
implies no change with location
over a specified region
uniform
a process during which a fluid flows through a control
volume steadily
steady-flow process
states that if two bodies are in thermal equilibrium with a third body, they are also in thermal equilibrium with each
zeroth law of thermodynamics
is defined as a normal force exerted by a fluid
per unit area
Pressure
The counterpart of pressure in solids is
normal stress
The actual pressure at a given position is called the
absolute pressure,
Atmospheric pressure is measured
by a device called a
barometer
