Prediction of batch heat transfer coefficients for pseudoplastic fluids ...
Prediction of batch heat transfer coefficients for pseudoplastic fluids ... Prediction of batch heat transfer coefficients for pseudoplastic fluids ...
22 C il _, aI' b l , cl' dl, el, fl' gl, hI' and jl are all constants to be evaluated. The group to the left of the equal sign is called the POv-Ter number. The first group to the right is the mixing Reynolds nmnber, and the second group to the l"ight is the Froude number. The Froude n~unber is required to account for the vortex formation in a s\-lirling system. Thus if baffles or off-center impeller location is used the Froude number is not needed. Host authors have also neglected the remaining groups and have specified a different value of C4 for each change in geometry. The effects of impeller style, blade Hidth, number of blades, impeller pitch, impeller clearance, Dt/Da, and spacing of multiple impellers have been studied by Bates et al. (12).. Richards (158) has studied the effect of impeller spacing, nurnber and 1.ddth of baffles, number and vddth of impeller blades, and the effects of coils. Host of the Horl~ on non-iJel.Jtonian systems has been similar but not as extensive.. BrOv.ffi and Petsiavas (31) have investigated the mixing of Bingham plastics. They found the P01-Jer number \hTaS a function of the Reynolds, Froude, and Hedstrom numbers.
2J Schultz-GrQnow (174) used a dimensional analysis but in a slightly different form for pseudoplastics 't~hich could be represented by the Pr~ndtl equation (2-18 where ApR and CpR are empirical constants. His results are plotte d as the log (l>1/Da 3 APR) versus.-lttiCPR l-vhere 1'-1 is the required torque and AI'" is the angular velocity. This result is not very general, h01.Jever, because the impellers studied are not connnonly used and most pseudoplastic fluids are best represented by the p011er laH or POHell-Eyring equation .. 1110 s t of the more general 1-lork has be en concerne d '-1i th finding a Viscosity term which can be used for all pseudoplastics as well as NeHtonian fluids. Magnusson (D2) found an apparent viscosity for pseudoplastics hy first developing a P01.Jer number-Reynolds number curve us ing the equipment geometry v.rhich was to be used for the pseudoplastic fluid. He then repeated the experiments with pseudoplastic fluids, calculating the POHer number for each value of agitator speed. By comparing the pseudoplastic data vJith the NevJtonian Pot.-rer number-Reynolds number curve an apparent Reynolds number could be calculated for the pseudoplastic fluid.. Th.e agitator difu"TIeter and speed "lATere lmOvffi as Vlell as the fluid density; thus the only unknown, the apparent viscosity, could be calculated. While this is a good method
- Page 1 and 2: Copyright Warning & Restrictions Th
- Page 3 and 4: PREDICTION OF BATCH HEAT TRANSFER C
- Page 5 and 6: while the latter has five to seven
- Page 7 and 8: ACKNOWLEDGEMENTS The auther ex~ress
- Page 9 and 10: Chapter 1: Chapter 2: Introducticm
- Page 11 and 12: LIST OF FIGURES page 2-1 FlGW Behav
- Page 13 and 14: CHAPTER I INTRODUCTION BATCH HEAT T
- Page 15 and 16: 3 as pseudoplasticso Pseudoplastic
- Page 17 and 18: 5 ~n addition to studying the effec
- Page 19 and 20: 7 A B SLOPE = /'n- .( 10 ~y FIG 2-1
- Page 21 and 22: 15.5, 183, 185).. Most of their eff
- Page 23 and 24: va:ry withl. the slaear I'Rte.. 11.
- Page 25 and 26: 13 RHEOLOGIC_~ INVESTIGATION OFPO~~
- Page 27 and 28: IS In(s) (2-8 (2-9 where Re is the
- Page 29 and 30: '7 ft~ easier method of calibrating
- Page 31 and 32: 19 of' thixotropic breakdown l'Ji t
- Page 33: 21 complicated by a variable viscos
- Page 37 and 38: 2S The results shm-red that equatio
- Page 39 and 40: Su.bstituti011 of equati 2-22 gives
- Page 41 and 42: 29 In both Newtonian and non-Newton
- Page 43 and 44: 31 for viscous pseudoplas tics at 1
- Page 45 and 46: 33 (2-29 when both the distances ar
- Page 47 and 48: JS Thermometers or thermocouples ar
- Page 49 and 50: .37 2: a in in heat cQ@tent of the
- Page 51 and 52: J9 cooling mediu..:m side, the heat
- Page 53 and 54: 41 ports a value of 3/4-.. He then
- Page 55 and 56: 43 find the effects of one or two o
- Page 57 and 58: 45 The group to the left of the equ
- Page 59 and 60: 47 the highest heat tra...nsfer coe
- Page 61 and 62: 49 A pitched blade turbine gave coe
- Page 63 and 64: SI done on the correlation of heat
- Page 65 and 66: 5J evaluated at the wall temperatur
- Page 67 and 68: ss to (2-46 where ill is the consis
- Page 69 and 70: CHAPTER .2 DEVELOPMENT OF CORRELATI
- Page 71 and 72: momentum" mass" and energy may be ~
- Page 73 and 74: 61 Vr;> Jt.- ,,"Ii'\... ..", ::: (V
- Page 75 and 76: 63 Substitution of these dimensionl
- Page 77 and 78: l/(R + 1) and was able t@ elim.iE.a
- Page 79 and 80: 67 All of the variables and differe
- Page 81 and 82: 69 The average heat transfer coeffi
- Page 83 and 84: N"v = C Iv''' (;';~-"')&'i'~ (%t-n,
2J<br />
Schultz-GrQnow (174) used a dimensional analysis but<br />
in a slightly different <strong>for</strong>m <strong>for</strong> <strong>pseudoplastic</strong>s 't~hich<br />
could<br />
be represented by the Pr~ndtl<br />
equation<br />
(2-18<br />
where ApR and CpR are empirical constants. His results are<br />
plotte d as the log (l>1/Da 3 APR) versus.-lttiCPR l-vhere 1'-1 is the<br />
required torque and AI'" is the angular velocity. This result<br />
is not very general, h01.Jever, because the impellers studied<br />
are not connnonly used and most <strong>pseudoplastic</strong> <strong>fluids</strong> are<br />
best represented by the p011er laH or POHell-Eyring equation ..<br />
1110 s t <strong>of</strong> the more general 1-lork has be en concerne d '-1i th<br />
finding a Viscosity term which can be used <strong>for</strong> all <strong>pseudoplastic</strong>s<br />
as well as NeHtonian <strong>fluids</strong>. Magnusson (D2) found<br />
an apparent viscosity <strong>for</strong> <strong>pseudoplastic</strong>s hy first developing<br />
a P01.Jer number-Reynolds number curve us ing the equipment<br />
geometry v.rhich was to be used <strong>for</strong> the <strong>pseudoplastic</strong> fluid.<br />
He then repeated the experiments with <strong>pseudoplastic</strong> <strong>fluids</strong>,<br />
calculating the POHer number <strong>for</strong> each value <strong>of</strong> agitator<br />
speed.<br />
By comparing the <strong>pseudoplastic</strong> data vJith the<br />
NevJtonian Pot.-rer number-Reynolds number curve an apparent<br />
Reynolds number could be calculated <strong>for</strong> the <strong>pseudoplastic</strong><br />
fluid..<br />
Th.e agitator difu"TIeter and speed "lATere lmOvffi as Vlell<br />
as the fluid density; thus the only unknown, the apparent<br />
viscosity, could be calculated. While this is a good method
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