Coulson Vol 1 Flashcards
Water in a tank flows through an outlet 25 m below the water level into a 0.15 m diameter horizontal pipe 30 m long, with a 90° elbow at the end leading to a vertical pipe of the same diameter 15 m long. This is connected to a second 90° elbow which leads to a horizontal pipe of the same diameter, 60 m long, containing a fully open globe valve and discharging to atmosphere 10m below the level of the water in the tank. Taking e/d — 0.01 and the viscosity of water as 1 mN s/m2, what is the initial rate of discharge?
Velocity= 3.12 m/s Nre= 4.68 x 10^5 Rate= 55 kg/s
A heat exchanger is to consist of a number of tubes each 25 mm diameter and 5 m long arranged in parallel. The exchanger is to be used as a cooler with a rating of 4 MW and the temperature rise in the water feed to the tubes is to be 20 deg K.
If the pressure drop over the tubes is not to exceed 2 kN/m2, calculate the minimum number of tubes that are required. Assume that the tube walls are smooth and that entrance and exit effects can be neglected. Viscosity of water= 1 mNs/m2.
Mass= 47.8 kg/s
Pressure drop= 0.204 m water
Velocity= 0.84 m/s
116 tubes
Crude oil is pumped from a terminal to a refinery through a 0.3 m diameter pipeline. As a result of frictional heating, the temperature of the oil is 20 deg K higher at the refinery end than at the terminal end of the pipe and the viscosity has fallen to one half its original value. What is the ratio of the pressure gradient in the pipeline at the refinery end to that at the terminal end? Viscosity of oil at terminal = 90 mNs/m2. Density of oil
(approximately constant) = 960 kg/m3. Flowrate of oil = 20,000 tonne/day.
Flowrate= 0.241 m3/s Velocity= 3.4 m/s Ratio= 0.80
A reaction vessel in a building is protected by means of a bursting disc and the gases are vented to atmosphere
through a stack pipe having a cross-sectional area of 0.07 m2. The ruptured disc has a flow area of 4000 mm2
and the gases expand to the full area of the stack pipe in a divergent section. If the gas in the vessel is
at a pressure of 10 MN/m2 and a temperature of 500 K, calculate: (a) the initial rate of discharge of gas,
(b) the pressure and Mach number immediately upstream of the shock wave, and (c) the pressure of the gas
immediately downstream of the shock wave.
Assume that isentropic conditions exist on either side of the shock wave and that the gas has a mean
molecular weight of 40 kg/kmol, a ratio of specific heats of 1.4, and obeys the ideal gas law.
85.7 kg/s
P up = 57 kPa
Mach no. = 4.15
P down= 1165 kPa
A gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, is flowing
through a pipe 0.25 m internal diameter and 5 km long at the rate of 0,4 m3/s and is delivered at atmospheric
pressure. Calculate the pressure required to maintain this rate of flow under isothermal conditions.
The volume occupied by 1 kmol at 273 K and 101.3 kN/m2 is 22.4 m3.
What would be the effect on the required pressure if the gas were to be delivered at a height of 150 m
(i) above and (ii) below its point of entry into the pipe?
P1 = 111.1 kPa
P1 above = 110.94 kPa (decreased)
P1 below = 111.26 kPa (increased)
Nitrogen at 12 MN/m2 is fed through a 25 mm diameter mild steel pipe to a synthetic ammonia plant at
the rate of 1.25 kg/s. What will be the drop in pressure over a 30 m length of pipe for isothermal flow of the
gas at 298 K?
Absolute roughness of the pipe surface = 0.005 mm.
Kilogram molecular volume = 22.4 m3.
Viscosity of nitrogen = 0.02 mN s/m2
-ΔP = 70 kN/m2
Q required = 3.12 W/m2
-ΔP (adiabatic)= 60 kN/m2
It is required to transport sand of particle size 1.25 mm and density 2600 kg/m3 at the rate of 1 kg/s
through a horizontal pipe, 200 m long. Estimate the air flowrate required, the pipe diameter and the pressure
drop in the pipe-line
Q air = 0.20 m3/s
size: 101.6 mm
- ΔPx = 16.5 kPa
- ΔP total= 26.8 kPa
The rate of flow of water in a 150 mm diameter pipe is measured with a venturi meter with a 50 mm
diameter throat. When the pressure drop over the converging section is 100 mm of water, the flowrate is
2.7 kg/s. What is the coefficient for the converging cone of the meter at that flowrate and what is the head
lost due to friction? If the total loss of head over the meter is 1 5 mm water, what is the coefficient for the
diverging cone?
CD= 0.985
head loss = 4.35 mm
C’D = 1.06
A gas cylinder containing 30 m3 of air at 6 MN/m2 pressure discharges to the atmosphere through a valve
which may be taken as equivalent to a sharp-edged orifice of 6 mm diameter (coefficient of discharge = 0.6).
Plot the rate of discharge against the pressure in the cylinder. How long will it take for the pressure in the
cylinder to Ml to (a) 1 MN/m2, and (b) 150 kN/m2?
Assume an adiabatic expansion of the gas through the valve and that the contents of the cylinder remain
constant at 273 K.
G = 0.0415 P1 kg/s.
Time to 1 MPa = 16,600 s
Time to 0.15 Mpa= 34,100 s
