Thermo5
Diffuser
A device that increases the pressure of a fluid by slowing it down
What is a nozzle?
A device that increases the velocity of a fluid at the expense of pressure
Nozzels and diffusers typically involve no
heat transfer or work
In a single-stream, stead flow system, the mass flow rate can be defined as the product of
Area, velocity, and density
What are throttle valves?
Flow-restricting devices that cause a pressure drop in a fluid.
What is usually neglected in the energy balance equation for a compressor with an intercooler?
Potential and Kinetic energy
True or false: The total energy for a flowing fluid consists of an additional term when compared with the total energy for a nonflowing fluid.
True, Both total energies consist of a combination of internal, potential, and kinetic energies. The total energy of a flowing fluid consists of an extra term, flow work.
Since liquid can be considered as incompressible, the volume flow rates into and out of a steady flow device will remain constant.
True, For a steady, incompressible flow, since the density is constant, it implies that the total volumetric flow rates entering and leaving a control volume are the same.
The steady-flow process is a process during which
a fluid flows through a control volume and does not change over time
The flow through a throttle valve may be assumed to be
adiabatic
Compressor
compressing gas to very high pressures
During a throttling process, if the flow energy increases due to significant increase of the specific volume, the temperature of a fluid will
decrease
The cross-sectional area of a nozzel
decreases in the flow direction for subsonic flows and increases for supersonic flows
Mass flow rate can be defined as the multiples of
density, pipe average velocity, and cross section area normal to the velocity
In an open system, when mass flows across control volume boundaries, some work is required to push the mass into or out of the control volume, and this is known as
flow work
Fan
increases the pressure of a gas. used to moblize gas
Any potential energy change in nozzels and diffusers can be
neglected
Which energies are part of the total energy of a flowing fluid?
potential and kinetic energy, enthalpy
A mass flow rate into a control volume is
proportional to the velocity component perpendicular to the cross-sectional area
During a steady-flow process, the fluid properties at an inlet or exit must ______.
remain constant
In a steady flow process, the changes of total energy of the control volume must
remain zero
For a single-stream, steady flow throttle valve, the inlet and outlet enthalpies can be approximated to be the
same
In a single-stream, steady-flow system, the mass flow rates for the inlet and outlet must be the
same
Pumps
similar to compressor except with liquids
Unlike steady flow processes, unsteady flow processes
start and end over some finite time period instead of continuing indefinitely
Mass flow rate is defined as
the amount of mass flowing through a cross section per unit time
Volume flow rate is defined as
the amount of the fluid flowing through a cross-section per unit time
Unsteady-flow or transient flow involves changes within
the control volume with time, such as charging or discharging problems
The steady flow implies that
the fluid properties can change from point to point, but at any point, they remain constant during the entire process
Why is velocity is never uniform across a cross section of a pipe?
the fluid sticking to the pipe wall will have zero velocity
Unsteady flow systems may involve boundary work
true
If properties are allowed to change within the control volume, the processes are called
unsteady flow
In a steady flow process, energy can be transferred by
work, mass, and heat
During a steady flow process, boundary work is
zero