Talk:Net positive suction head

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This should come under mechanical engineering, or just irrigation or pump technology. It is not directly related to bioengineering and the only link to chemical engineering is the vapor pressure aspect.  —Preceding unsigned comment added by Ozfreediver (talk • contribs) 08:12, 3 April 2010 (UTC)
thread_title:  wrong project 

message: Hello, I need some examples of NPSH calculation.. can you please post them?
NPSH = Psuction - Psaturation
please explain...  —Preceding unsigned comment added by Crackerbuzz (talk • contribs) 06:26, 20 September 2008 (UTC)
thread_title:  Headline text 

message: "A very important and interesting thing to note is that if you have an NPSHA of say 10 Bar then the pump you are using will deliver exactly 10 bar more over the entire operational curve of a pump than its listed operational curve."
I think this is just the difference between gauge and absolute pressure....
Mikejens (talk) 22:45, 13 November 2008 (UTC)
thread_title:  Atmospheric Pressure 

message: The definition of vapor pressure in the "somewhat simpler method of understanding NPSH…" section is wrong:
"Vapor pressure examples: (vapour pressure = the temperature in which a liquid turns into a gas, which may change under negative and positive pressure environments)."
The definition from http://en.wikipedia.org/wiki/Vapor_pressure is correct
"Vapor pressure (also known as equilibrium vapor pressure), is the pressure of a vapor in equilibrium with its non-vapor phases."
Vapor pressure is a strong function of temperature, but what is described in the section is boiling point (closely related - The boiling point of a substance is the temperature at which the vapor pressure equals the pressure seen by the fluid).
I am at work now (pump sizing!), but will attempt to clean up more of this mess today when I get some spare time.  I think the author knows what NPSH is, but he/she needs some help explaining it.  —Preceding unsigned comment added by 66.60.230.62 (talk) 13:02, 22 June 2009 (UTC)
thread_title:  This article needs SERIOUS work 

message: The equation for the NPSH should ADD the delta Z (not a minus)
Furthermore, nothing is said about the velocity head in the flow.  Total energy grade line (EGL) is the hydraulic grade line (HGL) plus the velocity head (V*V/2g), therefore, the "pressure" or the HGL that the fluid (and potential to cavitate) sees is the EGL - V*V/2g ..... or the Po + delta Z - Losses - V*V/2g
So if the velocity head is significant, the hydraulic pressure in the pipe is significantly LOWER and less NPSH is available.  —Preceding unsigned comment added by 72.164.173.2 (talk) 18:55, 12 August 2010 (UTC)
thread_title:  Wrong equation 

message: I have attempted to contribute some simple explanations of NPSH for readers that are without the relevant qualifications such as from a university etc. (Even then it is still a handful to read). The idea is to write it in a way for pump technicians and salesman to get a better understanding of the topic rather than just looking at NPSH curves and pretending to know what they are.
I have added only portions to assist.  Even so it is a very difficult topic to explain without getting technical!
If anyone can edit or add to assist or add simple calculations please do so.
Regards  — Preceding unsigned comment added by Crackerbuzz (talk • contribs) 08:58, 17 October 2011 (UTC)
thread_title:  Authors 

message: Please mention something about NPSH available and NPSH required. I don't think the technical description is adequate 
Kir360 (talk) 02:50, 13 June 2012 (UTC)
thread_title: Something About NPSHa and NPSHr

message: I have removed the section "A somewhat simpler informal way to understand NPSH" as definitely not in encyclopedic style. There may be useful information contained in it, but it needs reworking so I've moved it here. "Examples" needs work as well but I've let that stay. I will work on it further. Hyarmendacil (talk) 10:01, 24 April 2013 (UTC)
thread_title:  Moved section 

message: Whats Hf, z?
Further why is subscript 0 bolded, but i is itallic?  — Preceding unsigned comment added by 203.27.186.78 (talk) 23:02, 23 February 2021 (UTC)
replies: text: good work, your linked pdf is a much clearer explanation than the wikipedia article Effgee123 (talk) 02:25, 19 April 2023 (UTC)
thread_title:  Missing variable definitions