4 replies to this topic

[awesome]

Hello All,

My professor confuses me with these two terms Pressure drop and Pressure loss. They are one and the same right?
Or pressure loss is loss due to surroundings? well thats also pressure drop?
What are the software one can use for calculating these? Can Hysys can be used?

[fallah]

awesome,

In the field of fluid mechanic pressure drop is a consequence of pressure loss,but they could be considered as same issue.

Fallah

Edited by fallah, 19 June 2011 - 06:02 AM.

[EyMiller245]

To elaborate on Fallah's response

Technically, when someone refers to pressure loss, they are referring to the various mechanical forces that cause the pressure loss in the system (friction from the pipe wall, valves, turns in the pipe).

When one uses the term pressure drop, they are talking about the difference in pressure between two different points in the system. I.E. the pressure drop between points A and B is 20 psi.

As you can see, its very easy to interchange the two terms because they effectively mean the same thing.

[sheiko]

awesome:

Well, for me, pressure loss = NON-RECOVERABLE pressure drop.

For example, frictionnal pressure drop is a pressure loss, as the pressure energy is irreversibly transformed to thermal energy (heat).

Pressure drop due to the difference of static pressure (different elevations) between two points is recoverable (gravitational potential energy), so it is not a loss.

In a nutshell, total pressure drop = recoverable pressure drop (usually a difference of static pressure) + pressure loss (usually caused by friction during fluid flow).
Depending on your system, total pressure drop may be equal to one or the other term only.

Edited by sheiko, 08 August 2012 - 05:48 PM.

[blue_deer]

In ISO 5167-2 (2003), one can see the relationship between pressure loss & differential pressure which is illustrated in Equation (7) & Figure 5 of this international standard (for orifice plates).