Mixing Apparatus

7/30/2019 Mixing Apparatus

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C H E T 4 0 3 CHET403DEMONSTRATION OF THE MIXING POWER VARIATION LAB EXER. 17/1WITH IMPELLER TYP E, IMPELLER SPEE D, AND BAFFLE INCLUSION

NAME & NO.:_SECTION:

DATE:SCORE:

DEMONSTRATION OF THE MIXING POWER VARIATION WITHIMPELLER TYPE, IMPELL ER SPEED, AND BA FFLE INCLUSION

PERFORMANCE OBJECTIVEUpon completion of this experiment, the students will be able to :1. Show how the power of mixing of a fluid changes with the mixer (impeller) speed, type

of impeller, and with the inclusion of baffles.EQUIPMENT2. F luid mixing apparatus.3. Water and light to medium oil.4. F lat paddle and turbine impellers, and screw propeller.5. Set of baffles.

On/off switch M otorFlatbladepaddleH

SpeedcontrollerTurbine

Balance

H Propeller

M J J Balanceadjustment

Turbine Baff le Paddles DraincockFigure 1.

Y A NB U INDUS T R IA L CO LL E G E 230


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CHET 403 DEMONSTRATION OF THE MIXING POWER VARIATION LAB EXER. 17/2WITH IMPELLER TYP E, IMPELLER SP EED, AND BAFFLE INCLUSION

DISCUSSIONConsider a tank where a Newtonian fluid of density p , and viscosity p. is agitated by animpeller (agitator) of diameter Da and rotating at rotational speed a>. Let the tankdiameter be D , the impeller width W and the liquid depth H . The power requirement ofthe impeller P represents the rate of energy dissipation within the liquid and depends onthe following variables:P = (p,p,


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CHET 403 DEMONSTRATION OF THE MIXING POWER VARIATION LAB EXER. 17/3WITH IMPELLER TYP E, IMPELLER SPE ED, AND BAFFLE INCLUSION

8. Release the torque adjustment clamp, and allow the dynamometer to move freely.9. Set the dynamometer to a neutral position by using the setting bar and adjustment for

the tension spring.10. Increase the speed control knob in gradual increments and record the speed on thespeed indicator and the force on the balance at each speed of the mixer.

11. Repeat the procedure with the turbine impeller and other flat bladed paddles andagain with the four baffles in position with each impeller.

OBSERVATIONS AND RESULTS1. Tabulate the readings of angular speed u>and balance reading for the flat paddle and

turbine impellers, and screw propeller in Tables 1, 2, and 3, respectively.2. Calculate the power P consumption at different angular speeds co (rad/s) for the flatpaddle and turbine impellers, and screw propeller in Tables 4, 5, and 6, respectively.3. P lot the power consumption P (W) against the angular speed oo (rad/s) for the flat

paddle and turbine impellers, and screw propeller and discuss the shape of the plottedcurves.

4. Plot P (W) against w (rad/s) for the flat paddle impeller with and without baffleinclusion, and discuss the shape of the plotted curves

Table 1. Angular speed and balance readings (flat paddle impeller).Run# Angular speed,co (rpm) Angular speed,co (rad/s) Balance reading,(kg)

1 2002 3003 4004 5005 550

Y A NB U INDU ST R IA L CO LLE G E 230


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CHET 403 DEMONSTRATION OF THE MIXING POWER VARIATION LAB EXER. 17/4WITH IMPELLER TYP E, IMPELLER SPEE D, AND BAFFLE INCLUSION

Table 2. Angular speed and balance readings (turbine impeller).Run# Angular speed,co (rpm)

Angular speed,co (rad/s)

Balance reading,(kg)1 200

2 3003 4004 5005 550

Table 3. Angular speed and balance readings (screw propeller).Run# Angular speed,co (rpm) Angular speed,co (rad/s) Balance reading,(kg)

1 2002 3003 4004 5005 550

Table 4: P ower consumption at different angular speeds (flat paddle impeller).Run# Angularspeed, co(rad/s) Force, F (N)

Torque, r(Nm)Powerconsumption, P(W)

12345

Y A NB U INDU S T R IA L CO LL E G E 230


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CHET 403 DEMONSTRATION OF THE MIXING POWER VARIATION LAB EXER. 17/5WITH IMPELLER TYPE, IMPELLER SPEED, AND BAFFLE INCLUSION

Table 5: P ower consumption at different angular speeds (turbine impeller).Run#

Angularspeed, co(rad/s) Force, F (N)

Torque, r(Nm)Power

consumption, P(W)12345

Table 6: Power consumption at different angular speeds (screw propeller).Run# Angularspeed, co(rad/s) Force, F (N)

Torque, r(Nm)Powerconsumption, P(W)

12345

FINAL CHECK LIST1- C lean your workbench.2- Return all equipment to its proper location.3- Submit this exercise book (lab report) with all the data, calculations, and results

before the next lab session.

Y A NB U INDU ST R IA L CO L LE G E 230

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Mixing Apparatus