Sobika S

EXPERIMENT NO: 3 DATE:- POWER CONSUMPTION IN AGITATED VESSELS OBJECTIVE: ➢ To determine power consumption for different agitator system in an agitated Vessel 1. Radial impeller 2. Radial impeller with baffles 3. Axial impeller 4. Axial impeller with baffles ➢ To determine the flow type in agitator vessel at different mixing speed ➢ To determine the relation between Reynolds number and power number in agitated vessel for different agitator system PROCEDURE: ➢ Clean the agitator vessel, agitator impeller and stainless-steel baffles. ➢ Make sure the drain valve at the bottom of the vessel is closed and start filling the water inside the vessel. Fill ¾ to the volume of the vessel with water and check for any leaks before starting the experiment. ➢ Make sure the power supply is switched off while filling the vessel with water. ➢ Using the L type spanner fix the impeller to the shaft to complete the agitator set up. ➢ Once the agitator set up is ready, switch on the main power supply and initiate the mixing process by adjusting the speed of agitator using the speed regulator knob available. ➢ (NOTE: Always start with low speed and slowly increase the speed of agitator to fix the agitator speed at a particular rpm. Ex: To set the speed as 100 rpm, start with 10 rpm and gradually increase the speed to reach 100 rpm.) ➢ Once the agitation rpm is fixed, collect the Voltage and Ampere data from the display board in the unit. ➢ Repeat step 6 and 7 for different agitator speed and prepare the data table. ➢ After collecting the data for 4 to 5 different rpm levels, switch off the power supply. Fix the baffle plates to the side wall of the reactor in the provision provided. ➢ Repeat the experiment from step 5 to 8 and collect data for agitator unit with baffles system. Switch off the power supply and remove the impeller and baffles from vessel. ➢ Fix the other type of impeller and repeat the steps 4 to 10 and complete the data collection process. ➢ Calculate Reynolds number and Power number all the datasets and find the correlation between Reynolds and Power number using graphical method. FORMULA: POWER CONSUMPTION AND POWER NUMBER: P = 𝑁𝑝 𝑛3 𝜌𝐷5 𝑁𝑝 = 𝑃 𝑛3 𝜌𝐷5 Where , P = Rotor power (Watt) 𝑁𝑝 = Power Number 𝞀 = density of liquid(kg/𝑚3 ) 𝑛3 = Rotor/agitator speed measured in revolutions/second 𝐷5 =Rotor/impeller diameters (m) REYNOLDS NUMBER: 𝑁𝑅𝑒 𝐷2 𝑁𝜌 = 𝜇 DATA COLLECTION: RADIAL IMPELLER S.NO 1 2 3 4 5 𝑁𝑖 (rpm- Voltage(V- Current(A- RADIAL IMPELLER WITH BAFFLES S.NO 𝑁𝑖 (rpm) Voltage(V) Current(A) 1 100 38 0.20 2 200 67 0.26 3 300 98 0.34 4 400 130 0.46 5 500 166 0.63 S.NO 1 𝑁𝑖 (rpm) 100 Voltage(V) 32 Current(A) 0.05 2 200 60 0.08 3 300 76 0.09 4 5 400 500 98 135 0.11 0.14 AXIAL IMPELLER AXIAL IMPELLER WITH BAFFLES S.NO 𝑁𝑖 (rpm) Voltage(V) Current(A) 1 100 33 0.07 2 200 59 0.10 3 300 87 0.13 4 400 118 0.19 5 500 146 0.24 CALCULATION: REYNOLDS NUMBER: 𝑁𝑅𝑒 = 𝐷2 𝑁𝜌 𝜇 FOR ALL AGITATOR SYSTEM: 1. 2. 3. 4. 5. 0.472 ∗100∗-∗10−3 0.472 ∗200∗-∗10−3 0.472 ∗300∗-∗10−3 0.472 ∗400∗-∗10−3 0.472 ∗500∗-∗10−3 =- =24,566,346.9 =36,849,520.35 =49,132,693.8 =61,415,867.25 POWER CONSUMPTION AND POWER NUMBER: P = V*I FOR RADIAL IMPELLER: 37∗0.18 1. 𝑁𝑝 = 1003 ∗997∗0.475 2. 𝑁𝑝 = 2003 ∗997∗0.475 3. 𝑁𝑝 = 3003 ∗997∗0.475 4. 𝑁𝑝 = 4003 ∗997∗0.475 5. 𝑁𝑝 = 64∗0.21 90∗0.24 47∗0.27 144∗- ∗997∗0.475 = = = = = 6.66 22,865,-,925,577.6 21.6 617,373,824.3 12.69 1,463,404,621 44.64 2,- = 2.91*10−7 = 7.34*10−8 = 3.49*10−8 = 8.67*10−9 = 1.56*10−8 FOR RADIAL IMPELLER WITH BAFFLES: 1. 𝑁𝑝 = 38∗- ∗997∗0.475 = 7.6 22,865,697.2 = 3.32*10−7 𝑁𝑝 = 𝑃 𝑛3 𝜌𝐷5 67∗0.26 2. 𝑁𝑝 = 2003 ∗997∗0.475 3. 𝑁𝑝 = 3003 ∗997∗0.475 4. 𝑁𝑝 = 5. 𝑁𝑝 = 98∗0.34 5003 ∗997∗0.475 33.32 = = 5.39*10−8 617,373,824.3 = 4003 ∗997∗0.475 = 9.52*10−8 182,925,577.6 = 130∗0.46 166∗0.63 17.42 = 59.8 1,463,404,621 104.58 2,858,212,150 = 4.08*10−8 = 3.65*10−8 FOR AXIAL IMPELLER: 32∗0.05 1. 𝑁𝑝 = 1003 ∗997∗0.475 2. 𝑁𝑝 = 2003 ∗997∗0.475 3. 𝑁𝑝 = 3003 ∗997∗0.475 4. 𝑁𝑝 = 4003 ∗997∗0.475 5. 𝑁𝑝 = 60∗0.08 76∗0.09 98∗0.11 135∗- ∗997∗0.475 = = = = = 1.6 22,865,-,925,577.6 6.84 617,373,824.3 10.78 1,463,404,621 18.9 2,858,212,150 = 6.99*10−8 = 2.62*10−8 = 1.108*10−8 = 7.36*10−9 = 6.61*10−9 FOR AXIAL IMPELLER WITH BAFFLE: 33∗0.07 1. 𝑁𝑝 = 1003 ∗997∗0.475 2. 𝑁𝑝 = 2003 ∗997∗0.475 3. 𝑁𝑝 = 3003 ∗997∗0.475 4. 𝑁𝑝 = 5. 𝑁𝑝 = 59∗0.10 87∗0.13 118∗- ∗997∗0.475 146∗- ∗997∗0.475 = = = = = 2.31 22,865,-,925,577.6 -,373,824.3 22.42 1,463,404,621 35.04 2,858,212,150 = 1.01*10−7 = 3.22*10−8 = 1.83*10−8 = 1.53*10−8 = 1.23*10−8 CALCULATED DATA: NI REYNOLDS NUMBER POWER NUMBER RADIAL RADIAL BAFFLED AXIAL AXIAL BAFFLED 100 - 2.91*10−7 3.32*10−7 6.99*10−8 1.01*10−7 200 24,566,346.9 7.34*10−8 3.22*10−8 300 36,849,-*10−8 5.39*10−8 1.108*10−8 1.83*10−8 400 49,132,693.8 8.67*10−9 4.08*10−8 7.36*10−9 1.53*10−8 500 61,415,-*10−8 3.65*10−8 6.61*10−9 1.23*10−8 9.52*10−8 2.62*10−8 CORRELATION FOR 𝑁𝑅𝑒 AND 𝑁𝑝 AS GRAPH: 3.5E- POWER NUMBER 2.5E-E-E-08 0 0 - - - - - REYNOLD'S NUMBER Radial Rad w/baffle Axial Axial w/baffle - - DISCUSSION: • Power number is directly proportional to power consumption according to the formula, so with increase in power consumption power number increases. • From the graph of correlation between Reynold’s number and power number, it can be interpreted as, Radial agitator systems consume more power compared to the Axial agitator systems. • And also, greater the Reynolds number, the flow of fluid inside the agitator would be turbulent, which ensures good mixing pattern than laminar flow. • Here we can observe that, as the rpm increases, there is an increase in good mixing pattern due to the turbulent flow. So that, Axial impellers show good mixing pattern with less power consumption. • Axial impeller with baffle consumes slightly more power when compared to axial impellers. • As the Reynold’s number increases, Power number decreases, this profile is same for all four models. There is no variation here. • For all four models power number decreases with increase in rpm and Reynold’s number increases, which shows that, with increase in rpm there is an increase in good mixing pattern for all systems. • With lower power number and higher Reynold’s number, the flow is turbulent, which is observed in all four systems but the most efficient system is Axial and Axial with baffles agitators. • With change in flow regimes, different systems act in a similar way. • Power consumption is higher in Agitator with baffles when compared to systems without baffles. CONCLUSION: All four agitator systems perform well in mixing but some of these consume more power comparatively. The most efficient system with less power consumption is the Agitator system with Axial impeller