Getting The Wrong Answer
Getting The Wrong Answer
(OP)
I cannot figure out why MathCAD 14 is out putting the wrong answer.
I am doing a simple Power calculation using the formula:
P = BMEP * V.s * N/2 where
N = 4400rpm = 73.333rev/s
V.s = 2L = .002m^3
BMEP = 22bar = 2200000Pa
The correct answer is 161.3kW and MathCAD is giving 1014kW.
I uploaded the file for you to see.
Thanks for any help.
I am doing a simple Power calculation using the formula:
P = BMEP * V.s * N/2 where
N = 4400rpm = 73.333rev/s
V.s = 2L = .002m^3
BMEP = 22bar = 2200000Pa
The correct answer is 161.3kW and MathCAD is giving 1014kW.
I uploaded the file for you to see.
Thanks for any help.





RE: Getting The Wrong Answer
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RE: Getting The Wrong Answer
It looks like a confusion over appropriate units in the formula - the fundamental unit of cyclic frequency is rad/s = 2 pi x cycles/s. If you enter
N = ?
into Mathcad, it will return 460.767 1/s (i.e. rad/s), NOT 73.33 rev/s.
Hope this helps!
RE: Getting The Wrong Answer
You have N/2, so as rad = 2 pi, placing N/(4*pi) in your equation will give you the correct answer.
RE: Getting The Wrong Answer
I never took into consideration what MathCAD does to the revolutions and rad/s. It has been some time since I had to do any calculations involving them.
Once again thanks for the help.
RE: Getting The Wrong Answer