Coulson Fluid Flow Flashcards
Maging Engineer
The size analysis of a powdered material on a mass basis is represented by a straight line from 0 per cent at 1 μm particle size to 100 per cent by mass at 101 μm particle size. Calculate the surface mean diameter of the particles constituting the system.
21.7 μm
A material is crushed in a Blake jaw crusher such that the average size of particle is reduced from 50 mm to 10 mm, with the consumption of energy of 13.0 kW/(kg/s). What will be the consumption of energy needed to crush the same material of average size 75 mm to average size of 25 mm:
(a) assuming Rittinger’s Law applies,
(b) assuming Kick’s Law applies?
Which of these results would be regarded as being more reliable and why?
a) 4.33 kJ/kg
b) 8.88 kJ/kg
A spherical glass particle is allowed to settle freely in water. If the particle starts initially from rest and if the value of the Reynolds number with respect to the particle is 0.1 when it has attained its terminal falling velocity, calculate:
(a) the distance travelled before the particle reaches 90 per cent of its terminal falling velocity,
(b) the time elapsed when the acceleration of the particle is one hundredth of its initial value.
a) 1.05mm
b) t = 0.0016 s
Calculate the distance a spherical particle of lead shot of diameter 0.1 mm settles in a glycerol/water mixture before it reaches 99 per cent of its terminal falling velocity. The density of lead is 11,400 kg/m3 and the density of liquid is 1000 kg/m3. The viscosity of liquid is 10 mNs/m2. It may be assumed that the resistance force may be calculated from Stokes’ Law and is equal to 3πμdu, where u is the velocity of the particle relative to the liquid.
distance= 0.013 mm
What will be the terminal falling velocity of a glass sphere 1 mm in diameter in water if the density of glass is 2500 kg/m3?
Uo= 0.145 m/s
In a contact sulphuric acid plant the secondary converter is a tray type converter, 2.3 m in diameter with the catalyst arranged in three layers, each 0.45 m thick. The catalyst is in the form of cylindrical pellets 9.5 mm in diameter and 9.5 mm long. The void fraction is 0.35. The gas enters the converter at 675 K and leaves at 720 K. Its inlet composition is:
SO3 6.6, SO2 1.7, O2 10.0, N2 81.7 mole per cent
and its exit composition is:
SO3 8.2, SO2 0.2, O2 9.3, N2 82.3 mole per cent
The gas flowrate is 0.68 kg/m2s. Calculate the pressure drop through the converter. The viscosity of the gas is 0.032 mNs/m2.
−∆P= 3.9 kN/m2
A column 0.6 m diameter and 4 m high is, packed with 25 mm ceramic Raschig rings and used in a gas absorption process carried out at 101.3 kN/m2 and 293 K. If the liquid and gas properties approximate to those of water and air respectively and their flowrates are 2.5 and 0.6 kg/m2s, what is the pressure drop across the column? In making calculations, Carman’s method should be used. By how much may the liquid flow rate be increased before the column floods?
pressure drop= 0.118 kN/m2
L’= 4.3 kg/m2s
