Thread: I Need A Little Mathematic Help

I am out on the road and do not have my caculator and need some figures ran. I am typing this from my phone.

I need to know know what the percentage diffrence of these pipes sizes are.

2 3/4 to 2 7/8
2 7/8 to 3
3 to 3 1/8
3 1/8 to 3 1/4
3 1/4 to 3 3/8

I guess I am trying to find out how much air flow % one pipe has over the next.

I'm assuming pipe diameter in inches and you want cross section area.

2¾ to 2⅞ ...... 5.94 in² to 6.49 in² percentage difference of 8.5%
2⅞ to 3 ......... 6.49 in² to 7.07 in² percentage difference of 8.3%
3 to 3⅛ ......... 7.07 in² to 7.67 in² percentage difference of 8.0%
3⅛ to 3¼ ...... 7.67 in² to 8.30 in² percentage difference of 7.6%
3¼ to 3⅜ ...... 8.30 in² to 8.95 in² percentage difference of 7.3%

This does not take into account near-wall turbulence calculations.

Using (3.14)r^2 to calculate area

2 3/4 to 2 7/8 = 109% increase in area
2 7/8 to 3 = 109% increase in area
3 to 3 1/8 = 109% increase in area
3 1/8 to 3 1/4 = 109% increase in area
3 1/4 to 3 3/8 = 109% increase in area

2 3/4 to 3 = 119% increase in area
2 3/4 to 3 1/8 = 129% increase in area
2 3/4 to 3 1/4 = 139% increase in area
2 3/4 to 3 3/8 = 150% increase in area

oops ben is correct....I worded mine wrong. He was way more accurate with his decimal places/rounding as well. How mine should have read.

2 7/8 is 109% of the area of 2 3/4
3 is 109% of the area of 2 7/8
3 1/8 is 108.5% of the area of 3
3 1/4 is 108% of the area of 3 1/8
3 3/8 is 108% of the area of 3 1/4

2 7/8 is 109% of the area of 2 3/4
3 is 119% of the area of 2 3/4
3 1/8 is 129% of the area of 2 3/4
3 1/4 is 139% of the area of 2 3/4
3 3/8 is 150% of the area of 2 3/4

damn you fckers are smart !

x2