Skip to main content
added 115 characters in body
Source Link
xasthor
  • 1.1k
  • 12
  • 27

Flow work and energy for continuous fluid flow is calculated as $Pv$ enter image description here

This is explained in terms of the rest of the fluid pushing the back of a fluid element in consideration, which is described in terms of a hypothetical piston.

In a solved example involving air flowing uniformly and steadily, my textbook essentially uses the ideal gas law to solve for the rate of energy transport by mass. They write, $h=C_pT$ and $E=\frac{dm}{dt}(h+ke)$$E_{rate}=\frac{dm}{dt}(h+ke)$ since they have consolidated $u+Pv = h$ & neglected gravitational PE, and then they plug in values.

What I don't get is, these calculations are done for a "static" gas. The fact that it's flowing here doesn't seem to be accommodated for. Wouldn't the pressure $P$ used in calculating the flow energy have to include the additional force due to the liquid flowing?

EDIT: Here's how flow energy is defined and explained by my text

enter image description here

And also energy transport: enter image description here

Flow work and energy for continuous fluid flow is calculated as $Pv$ enter image description here

This is explained in terms of the rest of the fluid pushing the back of a fluid element in consideration, which is described in terms of a hypothetical piston.

In a solved example involving air flowing uniformly and steadily, my textbook essentially uses the ideal gas law to solve for the rate of energy transport by mass. They write, $h=C_pT$ and $E=\frac{dm}{dt}(h+ke)$ since they have consolidated $u+Pv = h$ & neglected gravitational PE, and then they plug in values.

What I don't get is, these calculations are done for a "static" gas. The fact that it's flowing here doesn't seem to be accommodated for. Wouldn't the pressure $P$ used in calculating the flow energy have to include the additional force due to the liquid flowing?

EDIT: Here's how flow energy is defined and explained by my text

enter image description here

Flow work and energy for continuous fluid flow is calculated as $Pv$ enter image description here

This is explained in terms of the rest of the fluid pushing the back of a fluid element in consideration, which is described in terms of a hypothetical piston.

In a solved example involving air flowing uniformly and steadily, my textbook essentially uses the ideal gas law to solve for the rate of energy transport by mass. They write, $h=C_pT$ and $E_{rate}=\frac{dm}{dt}(h+ke)$ since they have consolidated $u+Pv = h$ & neglected gravitational PE, and then they plug in values.

What I don't get is, these calculations are done for a "static" gas. The fact that it's flowing here doesn't seem to be accommodated for. Wouldn't the pressure $P$ used in calculating the flow energy have to include the additional force due to the liquid flowing?

EDIT: Here's how flow energy is defined and explained by my text

enter image description here

And also energy transport: enter image description here

added 149 characters in body
Source Link
xasthor
  • 1.1k
  • 12
  • 27

Flow work and energy for continuous fluid flow is calculated as $Pv$ enter image description here

This is explained in terms of the rest of the fluid pushing the back of a fluid element in consideration, which is described in terms of a hypothetical piston.

In a solved example involving air flowing uniformly and steadily, my textbook essentially uses the ideal gas law to solve for the rate of energy transport by mass. They write, $h=C_pT$ and $E=\frac{dm}{dt}(h+ke)$ since they have consolidated $u+Pv = h$ & neglected gravitational PE, and then they plug in values.

What I don't get is, these calculations are done for a "static" gas. The fact that it's flowing here doesn't seem to be accommodated for. Wouldn't the pressure $P$ used in calculating the flow energy have to include the additional force due to the liquid flowing?

EDIT: Here's how flow energy is defined and explained by my text

enter image description here

Flow work and energy for continuous fluid flow is calculated as $Pv$ enter image description here

This is explained in terms of the rest of the fluid pushing the back of a fluid element in consideration, which is described in terms of a hypothetical piston.

In a solved example involving air flowing uniformly and steadily, my textbook essentially uses the ideal gas law to solve for the rate of energy transport by mass. They write, $h=C_pT$ and $E=\frac{dm}{dt}(h+ke)$ since they have consolidated $u+Pv = h$ & neglected gravitational PE, and then they plug in values.

What I don't get is, these calculations are done for a "static" gas. The fact that it's flowing here doesn't seem to be accommodated for. Wouldn't the pressure $P$ used in calculating the flow energy have to include the additional force due to the liquid flowing?

Flow work and energy for continuous fluid flow is calculated as $Pv$ enter image description here

This is explained in terms of the rest of the fluid pushing the back of a fluid element in consideration, which is described in terms of a hypothetical piston.

In a solved example involving air flowing uniformly and steadily, my textbook essentially uses the ideal gas law to solve for the rate of energy transport by mass. They write, $h=C_pT$ and $E=\frac{dm}{dt}(h+ke)$ since they have consolidated $u+Pv = h$ & neglected gravitational PE, and then they plug in values.

What I don't get is, these calculations are done for a "static" gas. The fact that it's flowing here doesn't seem to be accommodated for. Wouldn't the pressure $P$ used in calculating the flow energy have to include the additional force due to the liquid flowing?

EDIT: Here's how flow energy is defined and explained by my text

enter image description here

edited title
Source Link
xasthor
  • 1.1k
  • 12
  • 27

The "type" of pressure used for finding the flow energy for a flowing fluid

Flow work and energy for continuous fluid flow is calculated as $Pv$ enter image description here

This is explained in terms of the rest of the fluid pushing the back of a fluid element in consideration, which is described in terms of a hypothetical piston.

In a solved example involving air flowing uniformly and steadily, my textbook essentially uses the ideal gas law to solve for the rate of energy transport by mass. They write, $h=C_pT$ and $E=\frac{dm}{dt}(h+ke)$ since they have consolidated $u+Pv = h$ & neglected gravitational PE, and then they plug in values.

What I don't get is, these calculations are done for a "static" gas. The fact that it's flowing here doesn't seem to be accommodated for. Wouldn't the pressure $P$ used in calculating the flow energy have to include the additional force due to the liquid flowing?

The "type" of pressure used for finding the flow energy

Flow work and energy for continuous fluid flow is calculated as $Pv$ enter image description here

This is explained in terms of the rest of the fluid pushing the back of a fluid element in consideration, which is described in terms of a hypothetical piston.

In a solved example involving air flowing uniformly and steadily, my textbook essentially uses the ideal gas law to solve for the rate of energy transport by mass. They write, $h=C_pT$ and $E=\frac{dm}{dt}(h+ke)$ since they have consolidated $u+Pv = h$ and then they plug in values.

What I don't get is, these calculations are done for a "static" gas. The fact that it's flowing here doesn't seem to be accommodated for. Wouldn't the pressure $P$ used in calculating the flow energy have to include the additional force due to the liquid flowing?

The "type" of pressure used for finding the flow energy for a flowing fluid

Flow work and energy for continuous fluid flow is calculated as $Pv$ enter image description here

This is explained in terms of the rest of the fluid pushing the back of a fluid element in consideration, which is described in terms of a hypothetical piston.

In a solved example involving air flowing uniformly and steadily, my textbook essentially uses the ideal gas law to solve for the rate of energy transport by mass. They write, $h=C_pT$ and $E=\frac{dm}{dt}(h+ke)$ since they have consolidated $u+Pv = h$ & neglected gravitational PE, and then they plug in values.

What I don't get is, these calculations are done for a "static" gas. The fact that it's flowing here doesn't seem to be accommodated for. Wouldn't the pressure $P$ used in calculating the flow energy have to include the additional force due to the liquid flowing?

Source Link
xasthor
  • 1.1k
  • 12
  • 27
Loading