FACULTY OF ENGINEERING SCIENCES
DEPARTMENT OF CHEMICAL ENGINEERING
CENG0020: ADVANCED SAFETY AND LOSS PREVENTION
Tutorial 2: Incompressible fluid flow rate equation for a
puncture in a tank
2The ‘Loss Model’
ConsequencePhysical EffectHazardous EventCause
e.g sudden release of
material or energy
e.g Human
error
e.g fire,
explosion,
toxic
release,
projectile
impact
e.g fatalities,
injuries or
environmental
damage
‘Minimise
or remove
altogether’
Frequency
mitigation
systems
Physical effect
mitigation
systems
Consequence
mitigation
systems
3The ‘Loss Model’
ConsequencePhysical EffectHazardous EventCause
Source Terms
Calculating the discharge rate following a leak from a tank
containing a liquid (incompressible)
4
https://www.youtube.com/watch?v=NtzvcbI6HFE&feature
=youtu.be
CENG0020: ADVANCED SAFETY AND LOSS PREVENTION
Derivation of Bernoulli’s Equation: Tank leak
Starting from the Bernoulli’s equation for an incompressible liquid flowing at steady state, ignoring
frictional losses given by:
where,
P = pressure
v = flow velocity
Z = height above the datum level
ρ = density
g = acceleration due to gravity
+
1
2
2 + =
+
1
2

2 +
CENG0020: ADVANCED SAFETY AND LOSS PREVENTION
with subscripts a and b representing the downstream and upstream conditions respectively, show that the
volumetric flow rate, Q from the side of a leaking tank containing an incompressible liquid is given by
where A, Cd and Pg are the puncture area, discharge coefficient and the gauge pressure in the tank
respectively. hL represents the height of liquid in the tank.