Part One
The thermal decomposition of n-butane was investigated in a
flow reactor at a pressure of 1 atm, in a temperature range of
460° to 560°C, and at low conversion levels, i.e. 0.06 - 0.68%
for the 460° runs, 0.5 - 2.3% for the 510° runs, and 3.5 to
8.2% for the 560°C runs. Temperature, velocity, and concentration
profiles at the exit end of the reactor were measured
to study the effects of energy, momentum, and mass transports
on chemical reaction. It was found after analysis of data
that the reactor could be treated as an isothermal reactor
with plug flow under the prevailing operating conditions.
Two rate expressions were determined for the reaction; one
corresponding to a first-order and the other to a second-order
rate. They are
First-order rate = 3.34 x 10^(12) e -54,600/RT (C_4H_(10) lb/ft^3 sec
Second-order rate = 2.55 x 10^(14) e -56,800/RT (C_4H_(10)^2 lb/ft^3 sec
These two expressions equally well represent the experimental
data.
On the basis of the products formed and the rates observed, a
Rice-type, free-radical mechanism was proposed for the thermal
decomposition of n-butane. The mechanism, which is presented
in the section on correlation of data, quantitatively describes
the reaction. One major feature of the mechanism is the consideration
of secondary reactions at very low conversions.
Part Two
Flow of an incompressible fluid at the entrance section of
parallel plates under isothermal, laminar conditions was investigated
by solving the two-dimensional Navier-Stokes
equations numerically. The Navier-Stokes equations were transformed
into finite-difference equations in terms of stream
functions ψ and vorticities ω with a technique developed by
de G. Allen. The finite-difference equations were then
solved by an iterative procedure on digital computers. From
the solution, point velocities and pressure gradients were
computed.
Two cases were studied, both with a Reynolds number of 300.
Case I had a flat velocity distribution at the entrance to the
plates. Case II assumed that potential-flow conditions existed
only far upstream from the entrance. For both cases, large
velocity and pressure gradients were found near the leading
edges of the plates, although they were comparatively smaller
in Case II. Also the velocity profiles for small distances
from the entrance were found to be slightly concave in the
central portion between the plates.
Schlichting and others have solved the boundary layer equation
for Case I. Their solu...