Hydraulic machines (Francis turbine)

AI Thread Summary
The discussion focuses on the mechanics of a Francis turbine, specifically the relationship between pressure and velocity as water moves through the turbine. It clarifies that the conversion from pressure to velocity occurs primarily in the stator, where fixed geometry accelerates the fluid and reduces pressure, allowing energy transfer to the rotor. The rotor then extracts energy from the fluid, which is not described by Bernoulli's equation. Participants also seek recommendations for books on hydraulic machines, with suggestions including "Strömungsmaschinen" by Carl Pfleiderer and "Strömungsmaschinen: Grundlagen und Anwendungen" by Herbert Sigloch. Understanding these concepts is essential for studying hydraulic machines effectively.
Mohankpvk
Messages
102
Reaction score
3
When my teacher was explaining about impulse-reaction inward
Radial flow (Francis) turbine, he said that as the water moves from inlet to outlet tip of the blade, pressure energy of the water is used to do work and pressure reduces(reaction effect).Then he added that due to this decrease in pressure,relative velocity between blade and water increases as water moves towards outlet.If this(pressure decreases velocity increases) comes from the Bernoulis equation then there should not be any addition or subtraction of energy from the fluid.But a turbine extracts energy from the fuid.So is this explanation wrong?
Please suggest a good book for studying the basics of hydraulic machines.
 
Engineering news on Phys.org
The conversion from pressure to velocity (when Bernoulli can be applied) mainly takes place before the fluid is entering the rotating wheel, in a stator. There a fixed geometry accelerates the fluid and decreases the pressure. The high-speed fluid then transfers energy (work) to the wheel applying a force on it and at the same time decelerates. So

stator: pressure ##\rightarrow## velocity (Bernoulli)
rotor: the fluid transfers work to the wheel (not Bernoulli)

Unfortunately I'm not familar with English books about hydraulic machines
 
  • Like
Likes Mohankpvk
stockzahn said:
The conversion from pressure to velocity (when Bernoulli can be applied) mainly takes place before the fluid is entering the rotating wheel, in a stator. There a fixed geometry accelerates the fluid and decreases the pressure. The high-speed fluid then transfers energy (work) to the wheel applying a force on it and at the same time decelerates. So

stator: pressure ##\rightarrow## velocity (Bernoulli)
rotor: the fluid transfers work to the wheel (not Bernoulli)

Unfortunately I'm not familar with English books about hydraulic machines

Please suggest a book.Langauge doesn't matter, Ill try to find a translated version of it.
 
"Strömungsmaschinen" (Turbo machinery) from Carl Pfleiderer - very good
"Strömungsmaschinen: Grundlagen und Anwendungen" (turbo machinery: Basics and applications) from Herbert Sigloch - not that substabial, but for the overview
 
  • Like
Likes anorlunda and Mohankpvk
Here's a video by “driving 4 answers” who seems to me to be well versed on the details of Internal Combustion engines. The video does cover something that's a bit shrouded in 'conspiracy theory', and he touches on that, but of course for phys.org, I'm only interested in the actual science involved. He analyzes the claim of achieving 100 mpg with a 427 cubic inch V8 1970 Ford Galaxy in 1977. Only the fuel supply system was modified. I was surprised that he feels the claim could have been...
Thread 'Turbocharging carbureted petrol 2 stroke engines'
Hi everyone, online I ve seen some images about 2 stroke carbureted turbo (motorcycle derivation engine). Now.. In the past in this forum some members spoke about turbocharging 2 stroke but not in sufficient detail. The intake and the exhaust are open at the same time and there are no valves like a 4 stroke. But if you search online you can find carbureted 2stroke turbo sled or the Am6 turbo. The question is: Is really possible turbocharge a 2 stroke carburated(NOT EFI)petrol engine and...
TL;DR Summary: Heard in the news about using sonar to locate the sub Hello : After the sinking of the ship near the Greek shores , carrying of alot of people , there was another accident that include 5 tourists and a submarine visiting the titanic , which went missing Some technical notes captured my attention, that there us few sonar devices are hearing sounds repeated every 30 seconds , but they are not able to locate the source Is it possible that the sound waves are reflecting from...
Back
Top