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