Pressure Washer Physics

tomtucson

tomtucson

New member
Since Nigel's been around I thought I would open up a thread for those who enjoy physics and math to analyze pressure washer related phenomena.

Todays question - How fast is the water going out the nozzle?

Speed (S) x Area (A) of nozzle = Volume (V) per unit time

S = V/A

So this volume can be converted to gallons and we should get the number

V x C = Gallons -> V = Gallons/C C = gallons/volume conversion factor


S = Gallons / C A given your gallons a minute and your nozzle area

I found that there is 231 cubic inches in a gallon so C = 1/231 gallons per cubic inch


So with area of my number 10 worn nozzle approximately 2/32" by 3/32" = 3/512" in sq
C = 1/231 in cubed
Gallons = 9 gpm

9 / (1/231) (3/512) = 354,816 in per minute = 29,568 ft per min = 492 feet per sec

Maybe there is a table of actual nozzle areas

And maybe there's a mistake here but it sounds like a reasonable number
 
5 out of 4 people dont like math.
 
tomtucson said:
Since Nigel's been around I thought I would open up a thread for those who enjoy physics and math to analyze pressure washer related phenomena.

Todays question - How fast is the water going out the nozzle?

Speed (S) x Area (A) of nozzle = Volume (V) per unit time

S = V/A

So this volume can be converted to gallons and we should get the number

V x C = Gallons -> V = Gallons/C C = gallons/volume conversion factor


S = Gallons / C A given your gallons a minute and your nozzle area

I found that there is 231 cubic inches in a gallon so C = 1/231 gallons per cubic inch


So with area of my number 10 worn nozzle approximately 2/32" by 3/32" = 3/512" in sq
C = 1/231 in cubed
Gallons = 9 gpm

9 / (1/231) (3/512) = 354,816 in per minute = 29,568 ft per min = 492 feet per sec

Maybe there is a table of actual nozzle areas

And maybe there's a mistake here but it sounds like a reasonable number
Click to expand...


In over my head Tom, I may seem like I do/refer to math often, but simple things often tie me up.
I guess is how you wrote it, I try to be overly simple in explanations because if I can get it anyone can.
Call me to explain
 
OK this is what I am saying - the nozzle is like a pasta machine and the water 'column' shooting out is the spaghetti, like an extrusion. In one minute that spaghetti 'tube' must be long enough to hold the GPM of the machine. The volume of that tube is the area of the nozzle-hole times the length of the tube. The length will be however many feet are needed, which will be the speed in feet per minute. or inches or whatever.
 
This is simpler

Area of nozzle hole times Length of water jet times 1/231 gallons per cubic inch = GPM of machine

A x L x 1/231 = GPM
(3/512) x L x(1/231) = 9

L = 354,816 inches per minute or 493 feet per second or 5.6 miles a minute.
 
Nigel the velocity is a rate. Should be possible to get a relation of velocity to gallons per time and integrate that?
 
outdoorprowash said:
Mass velocity and momentum

Sent from my DROID RAZR using Tapatalk 2
Click to expand...

Yes this was the next approach I wanted to work out after the velocity relation. Working from energy considerations is often the best approach. Homework for any math bugs?
 
I can see it now..
a scene from Jackass 7..
dude tries to rinse off a car going by at 100mph
.. with a 375mph water spray. (4000psi)

..somebody's going to get hurt
 
tomtucson said:
Since Nigel's been around I thought I would open up a thread for those who enjoy physics and math to analyze pressure washer related phenomena.

Todays question - How fast is the water going out the nozzle?

Speed (S) x Area (A) of nozzle = Volume (V) per unit time

S = V/A

So this volume can be converted to gallons and we should get the number

V x C = Gallons -> V = Gallons/C C = gallons/volume conversion factor


S = Gallons / C A given your gallons a minute and your nozzle area

I found that there is 231 cubic inches in a gallon so C = 1/231 gallons per cubic inch


So with area of my number 10 worn nozzle approximately 2/32" by 3/32" = 3/512" in sq
C = 1/231 in cubed
Gallons = 9 gpm

9 / (1/231) (3/512) = 354,816 in per minute = 29,568 ft per min = 492 feet per sec

Maybe there is a table of actual nozzle areas

And maybe there's a mistake here but it sounds like a reasonable number
Click to expand...

In English please?!
 
How many GPM are you looking at? And do you want the size of both pulleys, or do you already have one that you want to use, that you picked up at Harbor Freight?
 
Basic Power Washing Math, hope this helps someone.
attachment.php
attachment.php
attachment.php
attachment.php
attachment.php
attachment.php
 

Attachments

  • Capture 1.JPG
    Capture 1.JPG
    75.3 KB · Views: 98
  • Capture 2.JPG
    Capture 2.JPG
    80.8 KB · Views: 99
  • Capture 3.JPG
    Capture 3.JPG
    80.6 KB · Views: 101
  • Capture 4.JPG
    Capture 4.JPG
    73 KB · Views: 99
  • Capture 5.JPG
    Capture 5.JPG
    167.8 KB · Views: 99
  • Capture 6.JPG
    Capture 6.JPG
    76.1 KB · Views: 99
Last Page
attachment.php
 

Attachments

  • Capture 7.JPG
    Capture 7.JPG
    112.2 KB · Views: 99
You must log in or register to reply here.
Back
Top