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 ...
20 l'UXIlfG OF NON -NE1rJTONIAN FLUIDS The mixing of non-Newtonian fluids in an agitated vessel is a 'lIDi t operation somel'1fhat similar to batch heat transfer. It is presented because some of the results of the Hork on mixing can be utilized in developing a correlation for predicting batch heat transfer coefficients. Batch heat transfer could be classified as a problem involving the quality of mixing but it is usually considered as a separate study. A review of the small amount of Hork on batch heat transfer to non-Nel'ITtonian fluids will be considered later in this chapter. This section reviel'JS the study of pov-rer requirements and the quality of mixing. Much of the work on fluid flow and heat transfer to pseudoplastics in pipes (revie'tved in \1Iilkinson.1 213; Metzner, 118; and Thomas, 190) was theoretical in nature. The geometry and flO1..J patterns in an agitated vessel, hmvever, are rather complex for this approach. The velocity profile in a pipe could be quantitized since it was only a function of wall shear stress, average velocity, and rheological parameters. In addition the flow Has in only one direction. In a mixing vessel the floH is three dimensional, the "\-lall shear stress is QnY~OHn, and the average velocity is not only difficult to define, but is dependent upon the rheological properties, the speed of the agitator, the shape, dimensions, and position of the agitator, and the vessel geometry.. Because of great number of 'lIDknown relationships, which are made even more
21 complicated by a variable viscosity, all of the 1~ork to date has been experimental rather than theoretical. Power Requirements POl.'lTer requirements for Newtonian fluids have been studied by many investigators and are summarized in many good reviel.Js (12, 9~., 142, 158,162,163 ) • The approach used vJas to def'ine the variables and use dimensional analysis to combine these variables into dimensionless groups.. An all inclusive analysis is given by (12,158) where P N is the power requ~red. is the rotational speed of' agitator. D' a. is the diameter of' the agitator. D t is the diameter of' the vessel. IlL Hc is the liquid height. is the clearance between impeller bottom and vessel bottom. is the width of' the agitator. is the baf'fle 1.Jid th .. is the number of baffles. is a reference n~unber of baffles. is the number of blades on the impeller. is a reference number of blades on the impeller ..
- 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: 19 of' thixotropic breakdown l'Ji t
- Page 35 and 36: 2J Schultz-GrQnow (174) used a dime
- 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
21<br />
complicated by a variable viscosity, all <strong>of</strong> the 1~ork<br />
to<br />
date has been experimental rather than theoretical.<br />
Power Requirements<br />
POl.'lTer requirements <strong>for</strong> Newtonian <strong>fluids</strong> have been<br />
studied by many investigators and are summarized in many<br />
good reviel.Js (12, 9~., 142, 158,162,163 ) • The approach used<br />
vJas to def'ine the variables and use dimensional analysis to<br />
combine these variables into dimensionless groups..<br />
An all<br />
inclusive analysis is given by (12,158)<br />
where P<br />
N<br />
is the power requ~red.<br />
is the rotational speed <strong>of</strong>' agitator.<br />
D' a.<br />
is the diameter <strong>of</strong>' the agitator.<br />
D t<br />
is the diameter <strong>of</strong>' the vessel.<br />
IlL<br />
Hc<br />
is the liquid height.<br />
is the clearance between impeller bottom and<br />
vessel bottom.<br />
is the width <strong>of</strong>' the agitator.<br />
is the baf'fle 1.Jid th ..<br />
is the number <strong>of</strong> baffles.<br />
is a reference n~unber<br />
<strong>of</strong> baffles.<br />
is the number <strong>of</strong> blades on the impeller.<br />
is a reference number <strong>of</strong> blades on the impeller ..
Change language