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FOR LIQUID-LEVEL PROCESSES,
T = AR
[ Rate of mass flow in] – [Rate of mass flow out] = [Rate of accumulation of mass in tank]
p q (t) – p q0 (t) = d (p Ah) dt
Find T and R
T= ART = A ( hs )
qsT = Vs = 200 gal = 5 min
qs 40 gal/min
R = Vs = 200 gal = 26.733 ft3
A Qs (∏(3 ft2) (40 gal/min) (∏ (3 ft)2) (5.346 ft3/min)
= 0.1768 ft /ft3/min
FOR AN IMPULSE OF 55 GAL = 7.352 ft3
Q(s) = 7.352
H (s) = (7. 352) (0.1768) = 1.299835s + 1 5s + 1
H (s) = 0.25996672s + 1/5
H (t) = 0.25996672 e-t/5
For question (a)
a) Will the tank overflow?
Answer: No
Find initial height.
H = 200 gal = 26. 733 ft3
A ∏ ( 3 ft2 )
H = 0.9455 ft
at t = 0 maximum change in height happens
h = 0.9455 + H (t)h = 0.9455 + 0.25946672 e-t/5
h = 1.205 ft THE TANK WILL NOT OVERFLOW
b ) Plot the height as f (t) starting at t = 0
Equation is f(t) = 0 .9445 + 0.25996672 e-t/5
Use simulink to show
Height Response
Assume Amplitude or % Period and Period
Amplitude = 10, 000Period = 100% Period= ?
55 gal = 7. 352 ft3 = (% period) (100) (10,000)100
% period = 0.0007352
Flow Rate Response
Amplitude = 10,000Period = 100% period = 0.0007352
c) For output flow
Q0(s) = 1 = Q0(s) = 7.352Ts + 1 5s + 1
Q0(s) = 1.4704s + 1/5
Q0(t) = 1.4704 e-t/5
Qo(actual) = 5.3466 ft3+ 1.4704e-t/5
Use simulink to verify.