Pressure, Velocity and Nozzle ||Engineering Minutes ||
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- เผยแพร่เมื่อ 16 ต.ค. 2024
- there are many people who believe that water jet has higher pressure which is coming out of nozzle. they believe that pressure is inversely proportional to area. and here area is decreasing over length so pressure must be increasing. but is it so?
for answer check out our video. if there are any doubts, than you can comment it in below comment section.
thank you.
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Bernoulli equation consists of pressure head velocity head and potential head as said in this video the energy and momentum is conserved one head decreases automatically and the other head increases. So as the area decreases velocity increases and we see a drop in static pressure. But as velocity increases of water jet it will apply more force on its target and that too on a smaller area.
So greater the force on smaller area will simply increase the impact pressure.
Exactly!
P=F/A , F=ma and a= delta v/t right?, combine all these equations and we get P= mv/tA , according to which pressure is directly proportional to velocity, Why is Physics defying itself or am I confused?
He is confusing two different equations & criteria.
Bernoulii’s equation (which is talking about hydrostatic pressure or pressure on walls) while here the equation applied is P=F/A which relates pressure of liquid in motion (means Here F at discharge is high due to acceleration and less Area so that also increases Pressure)
p=L*(A/x) where: L is mechanical work (dinamic presure), A area of the pipe section, x distance from the pump, p static presure in a given point
As you can see static presure drops with the increase of distance.
Also Q=√(p§A²) where § is density Q is masic flow
As you can see flow decrees with the decrease of static pressure.
So flow decrees with the increase of distance from the pump 😂
I've heard alot of internet self proclaimed "tehnical/scientific gurus" say that flow is constant along the pipe 🤦🤣 They have no idea what they are talking about.
Flow is constant IN ONE GIVEN SECTION of the pipe 😂 but not along the pipe 😂
p=L*(A/x) and L=m*v
So v=(p*x)/(m*A)
As you can see speed decrees with the increase of distance from the pump and increase with the decrease of the area of a section 😂 This is the right explanation why fluid's speed increases in a nozzle 😂
The analogy with the water free flow is wrong because pressure increases towards the end of the pipe due to the weight of the water column 😂
When the pipes are not horizontal things get more complicated because the mass of the fluid could be considerable. It can be neglected only in small hydraulic installations, like cooling, lubrication and fuel system of a car for example. But becomes significant if we talk about a water supply system for a city.🤷
Most engineering problems can't be solved by using pure theoretical math. Math is used to get a close enough value then the value is corrected using coefficients determined by experiments. 🤷
Engineering is doing a very accurate guess work 🤣
Is the pressure of liquid equal to atmospheric pressure when it comes out of the pipe ?
Yes. It doesn’t matter if the water is dribbling out or blasting out hundreds of feet, the pressure is zero.
@@RiffMusic1970so if I have 70psi with 0.1m/s going towards a household, does it mean the household will not actually get a good amount of flow?
What if it is 0.7psi but with 2.0m/s velocity?
During the design of a network, would the designer prefer a good pressure or a good velocity? The designer has to choose between:
1. High pump head (high opex), smaller pipe diameter (low opex)
(high pressure (60-70psi), good velocity (1-2m/s))
2. Low pump head (low opex), larger pipe diameter (high capex)
(good pressure (20-30psi), good velocity (1-2m/s)
@@rcane6842 not sure what point you’re making but it doesn’t matter if the pressure is 70 psi or .7 psi, when it’s coming out of the faucet the pressure is zero was the point I was making.
In this case of washing car
And reduce the section area by thumb p is reduced and v is increase??
Yes
"Flow of water must be from higher pressure to lower pressure and here we can say that water is flowing through nozzle so we can say that higher pressure on left side and lower pressure on right side."...I wasn't satisfied with this explanation. Could you please explain about the higher pressure on left side and lower pressure on right side....
You must be, because potential difference ( it can be produced by pumping action which we can say an external force) must be required for flow of water.
On right side atmospheric pressure consider 1atm and on the left there has to be a device that pumps the water or the tank is at higher altitude in both the cases pressure on left is high due to this pressure difference water flows
but in diffuser, lhs low pressure and rhs high pressure
Do you ever heard about total energy gradient concept...if not than please search..or else we can make a video about it.
@@engineeringminutes5997 do make a video plis
Great video, but stay away from the filler words such as "O.K.", you are very clear in your explanation, but when you state "O.K.", you interrupt the train of thought and flow of your information because you are either asking us a question and not allowing us to think of the answer before you continue on your very good instructional video. Lastly, use some real-world numbers that are found around the house such as garden hose pressure of 60 to 120 psi with a flow of 3 to 5 gallons per minute with the velocity of the water and the distance of travel if held at a 45 degree angle, which for me is 25 feet at Latitude 32 degrees north and 245 feet above sea level. What I liked the most of your video is the animational cartoons and formula development. Thank you again for the great video.
Thank you @menkeyman. Critisism and suggestions are always accepted. Thank you once again!
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Sir mujhe ek baat bataye agar straight pipe ke ek or mai compressor laga du aur usse high pressure release karu to pipe ke andar ka fluid ki velocity bhi badhegi uss high pressure ke badhne se to pressure or velocity inversely proportional kaisa hua please ek real example deke samjhaye
Please reply sir
Aapke question me hi aapka answer he, jab hum compressor laga rahe he to hum ek energy source add kar rahe he bahar se to humme us external energy ko bhi consider karna padega..lekin yaha par Bernoulli ke principle me baat energy comparision ki ho rahi he...to agar aap compressor lagate ho to bhi uske baad k two points ki energy comparision karte ho or agar cross section bhi change ho raha he to result same hi rahega...i hope it will be clear...but you can watch our next video on it for the practical problem.
How pressure is decreasing physically while going from More to lesser cross. Section with high velocity?? Sir
In terms of molecular physics, pressure is nothing but random collision of molecules with wall. As we know that kinetic energy increases with lesser cross section(according to mass conservation law) there should be more aligned motion of particles to get higher net velocity. That causes reduction in random collision of particles with wall. I hope you get this.
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If area and velocity are inversely proportional and area n pressure are inversely proportional then velocity and pressure should be directly connected..Pls comment anyone..
It is not like that, velocity is inversely proportional to area only when volume flow rate is constant..and here it is constant..and about pressure, it is not only inversely proportional to area also dependent on force..but anyhow we are talking about total pressure rather than static pressure.
Bernoulli equation consists of pressure head velocity head and potential head as said in this video the energy and momentum is conserved one head decreases automatically and the other head increases. So as the area decreases velocity increases and we see a drop in static pressure. But as velocity increases of water jet it will apply more force on its target and that too on a smaller area.
So greater the force on smaller area will simply increase the impact pressure.
Area and pressure are NOT inversely proportional. Area and pressure are directly proportional.
When the area increases, pressure increases. When the area decreases, pressure decreases.
For constant cross section area of pipe. What is the relationship b/w pressure and velocity
That relationship is established with help of Bernoulli's principle. With constant CS, total energy remains constant. And that can be helpful to define relationship. You can refer RK Bansal flow through pipes.
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I am looking for short answer to summarize the whole video any one have that answer? Because P=F/A and its clearly says if the area increased pressure will be reduced and unfortunately thats not what happen, BUT WHY? IN SIMPLE ANSWER WHY? PLZ HELP
Pressure following F/A equation but at the same time it also follows Bernoulli's equation. That's the main reason .
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Pressure does not decrease when area increases. Pressure increases when area increases.
Why is the volume so low
great job.
Very nice man😀😀😀
w
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I have prove that pressure is dirctly propor to vel .... If you are genius then make video on them
Please share your proof...here everyone come for knowledge only..
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Sir sorry it is secret
I have give word to my teacher
That's why cc disappear
Very nice way to explain.
Thanks ..
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speak louder please