exp 5 baffle turbine
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7/23/2019 Exp 5 Baffle Turbine
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EXPERIMENT # 12
Date: 16-12-2013
OBJECT
Perform the operation of mixing and show an analysis of eects of
dierent sizes of turbine on mixing.
THEORY
Mixing is one of the common operations carried out in the chemical
processing and allied industries. The term mixing is applied to the processes
used to reduce the degree of non-uniformity, or gradient, a property in a system
such as concentration, viscosity, temperature and so on. Mixing is achieved by
moving materials from one region to another. t may be of interest simply as a
means of achieving a desired degree of homogeneity but it may also be used to
promote heat and mass transfer, often where a system is undergoing a chemical
reaction.
APPARATUS
Mixing tan!, variable speed motor, dierent size turbines, ba"es, p#
meter and small bea!ers.
PROCEDURE
$dd water so that the height becomes e%ual to the diameter of the tan!.
Ta!e four ba"es all should be of same size.
&tart the motor and add concentrated base.
$fter every '( seconds, ta!e out a sample of about )*ml. $fter each sample, add )*ml water so that the level of water remains
constant.
+hile !eeping the speed at optimum. epeat the experiment for dierent
size turbines.
raw graph for the change in p# for each turbine size. etermine the
optimum turbine size.
&cale up the results times.
OBSERVATIONS
200 Rpm and 2.2cm bafe with
5cm turbine size
200 Rpm and 2.2 cmbafe with 6cm
turbine size
200 Rpm and 2.2 cmbafe size with 7cm
turbine size
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Time/sec0 p#
* .12
'( '*.3
)* '*.42
3( '*.43
1* '*.41
5( '*.41
4* '*.45
'*( '*.4
'2* '*.4
')( '*.4
'(* '*.4
'1( '*.4
'* '*.4
'4( '*.4
Time/sec0 p#
* .('
'( '*.4
)* '*.42
3( '*.43
1* '*.42
5( '*.4(
4* '*.43
'*( '*.43
'2* '*.4(
')( '*.43
'(* '*.4(
'1( '*.4(
'* '*.4(
'4( '*.4(
2'* '*.4(
22( '*.4(
Time/sec0 p#
* .(
'( '*.5
)* '*.54
3( '*.4)
1* '*.4)
5( '*.4)
4* '*.4(
'*( '*.4(
'2* '*.4(
')( '*.4(
'(* '*.41
'1( '*.41
'* '*.41
'4( '*.41
2'* '*.41
22( '*.41
200 Rpm and 2.2 cm bafe with 5cm turbine size
* (* '** '(* 2** 2(*
.(
4
4.(
'*
'*.(
''
''.(
Time (sec)
pH
200 Rpm and 2.2 cm bafe with 6cm turbine size
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* (* '** '(* 2** 2(*
.(
4
4.(
'*
'*.(
''
''.(
Time (sec)
pH
200 Rpm and 2.2 cm bafe size with 7cm turbine size
* (* '** '(* 2** 2(*
.(
4
4.(
'*
'*.(
''
''.(
Time (sec)
pH
Time/sec0
6. turbine/cm0
'*( (
'(* 1
'(* 5
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5( 4( ''( ')( '(( '5(
3
(
1
5
Time (sec)
O T!"i$e (cm)
RESU%T
The optimum turbine size is found to ( cm.
DISCUSSION$gitation is means whereby mixing phases can be accomplished and by
which mass and heat
transfer can be enhanced between phases or external surfaces. The operation of
agitation, which includes mixing as a special case, is now well established as an
important and in a wide variety of chemical processes.
&peci7cally, agitators are applied to three general classes of problems8
To produce static or dynamic uniformity in multi component multiphase
systems.
To facilitate mass or energy transfer between the parts of a system not ine%uilibrium.
To promote phase changes in multi component system with or without a
change in compositions.
Mixing in tan!s is an important area when one considers the number of
processes, which are accomplished in tan!s. 9ssentially, any physical or
transport process can occur during mixing in tan!s. :ualitative and %uantitative
observations, experimental data, and ;ow regime identi7cations are needed and
should be emphasized in any experimental pilot studies in mixing. $ vortex is
produced owing to centrifugal force acting on the rotating li%uid. f vortex
reaches the impeller severe air entrainment occurs. The depth and the shape ofthe vortex depend on impeller and vessel dimensions as well as on rotational
speed.
Mixing e
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the shaft. n ba"ed tan!s, a better concentration distribution throughout the
tan! and therefore improvement in the mixing ePM. Turbine should be operating below critical speed
which is speed at which both fre%uencies of turbine /vibration and rotational0reinforce one another.
n our experiment it is observed that for same ba"e size, the e
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