(1) Describe briefly the definition of fully developed laminar
flow.
(2) From governing laws for fully developed laminar flow, derive
an equation for fully developed laminar flow that shows the
relation between flowrate and pressure gradient.
Convection Heat transfer internal flow
Consider water flowing in a heated tube. The tube is 14 m long
with an inner diameter of 1 cm. The heat
is added at 1500 W/m2 uniformly along the tube. Water flows at 0.3
m/s. Use the following water property
? = 1000 kg/m3, ? = 1.4 × 10?3 kg/m·s, cp =
4.2 kJ/kg·K, k = 0.58 W/m·K, and determine
1. Heat transfer coefficient at the tube exit.
2. Tube surface temperature at the...
Concept 1: Does turbulent flow or laminar flow have a greater
heat transfer coefficient? Why?
Concept 2: For flow over a flat plate, why does the heat
transfer coefficient decrease the greater the distance from the
leading edge? (in answering, ignore the effects of flow regime
transitions. i.e. assume the flow over the plate is all laminar or
all turbulent).
Fully developed (both hydrodynamic and thermal) laminar flow is
pushed through a thin-walled circular pipe of diameter 13 mm. The
fluid flows through the pipe at a velocity of 0.1 m/sec, has a
density of 1000 kg/m^3, a dynamic viscosity of 855 x 10^-6 Pa-sec,
a specific heat of 4000 J/kg-K, a Prandtl number of 8, and a
thermal conductivity of 0.613 W/(m-K).
The outside of the pipe is subjected to uniform cross flow where
the free-stream velocity is 5...
A steady two-dimensional laminar fully-developed flow downward
between
two fixed parallel plates inclined at 50" with horizontal is
shown in figure. The
pressure gradient in the direction of the flow is -3935 N/m' per
m. Note the
space between parallel plates is 5mm.Use the Navier-Stokes
equation in the
flow direction to determine:
a-Velocity distribution of the flow between two plates.
b-Shear stress distribution of the low between two plates.
c- The average velocity of the flow
d- Maxinmum velocity
e-Mininmum...
Heat transfer
In a test in a double tube heat exchanger the following data are
obtained
For hot fluid
Flow = 11.6 gal / sec
Outlet temperature = 30.1 ° C
Inlet temperature = 32 ° C
For cold fluid
Flow 11gal / min
Outlet temperature 25.1 ° C
Inlet temperature 24.2 ° C
For the fluid consider
k = 0.49 w / mK
cp = 3729.95 J / kgK
Prandtl number = 14.29
Density = 1035.02kg / m3
Get:...
Heat transfer
in a test in a double tube heat exchanger the following data are
obtained
For hot fluid
Flow = 11.6 gal / sec
Outlet temperature = 30.1 ° C
Inlet temperature = 32 ° C
For cold fluid
Flow 11gal / min
Outlet temperature 25.1 ° C
Inlet temperature 24.2 ° C
For the fluid consider
k = 0.49 w / mK
cp = 3729.95 J / kgK
Prandtl number = 14.29
Density = 1035.02kg / m3
Get:...
HEAT TRANSFER: HEAT EXCHANGER
Oil flows in a heat exchanger with a mass flow rate of 20 kg/s
and is to be cooled from 175 to 65°C with water as a coolant
flowing at a rate of 30 kg/s and an inlet temperature of 12°C. The
overall heat transfer coefficient is U = 1250
W/m2⋅K.
a) Sketch the temperature profile and calculate the mean
temperature for parallel flow, counter flow, and cross flow heat
exchangers..
b) Determine the area required...