Fluid originally flows through a tube at a rate of 185 cm3/s. To illustrate the
ID: 1546469 • Letter: F
Question
Fluid originally flows through a tube at a rate of 185 cm3/s. To illustrate the sensitivity of flow rate to various factors, calculate the new flow rate for the following changes with all other factors remaining the same as in the original conditions.
(a) The pressure difference increases by a factor of 1.23. cm3/s
(b) A new fluid with 3.60 times greater viscosity is substituted. cm3/s
(c) The tube is replaced by one having 4.00 times the length. cm3/s
(d) Another tube is used with a radius 0.100 times the original. cm3/s
(e) Yet another tube is substituted with a radius 0.100 times the original and half the length, and the pressure difference is increased by a factor of 1.21. cm3/s
Explanation / Answer
fluid rate a=185 cm^3/sec
use,
a=pi*r^4*dp/8*u*l
a)
dp2=1.23*dp1
===>
a'=1.6*a
a'=1.6*185
a'=296 cm^3/sec
b)
u'=3.6*u
==>
a'=a/3.6
a'=185/3.6
a'=51.4 cm^3/sec
c)
l'=4*l
===>
a'=a/4
a'=185/4
a'=46.25 cm^3/sec
d)
r'=0.1*r
===>
a'=0.1^4*a
a'=0.1^4*185
a'=0.0185 cm^3/sec
e)
r'=0.1*r
l'=0.5*l
p'=1.21*p
===>
a'=(0.1^4*1.21)/0.5*a
a'=0.000242*a