Page 16 - Fluid mechanics, heat transfer, and mass transfer

LIST OF FIGURES xix

6.2 A basic stirred tank design showing a lower 7.15 Pneumatic conveyor: positive system. 213
radial impeller and an upper axial impeller 7.16 Blind tee and blind bend with arrows showing
housed in a draft tube (not to scale). Four impact points. 216
equally spaced baffles are standard. 171 7.17 The regimes of flow for settling slurries
6.3 Multistage agitator with baffles and sparger in horizontal pipelines. 219
for gas–liquid reactors. 172 7.18 Schematic representation of the boundaries
6.4 Turbine and propeller mixers. 173 between the flow regimes for settling slurries
6.5 Marine, saw-toothed, and perforated propellers. 174 in horizontal pipelines. 219
6.6 Flat plate impeller with sawtooth edges. 175
6.7 Different types of turbine impellers. 175 Heat Transfer
6.8 Gate and leaf impellers. 176
6.9 Draft tube agitator. 177 8.1 Illustration for triple point. 226
6.10 Incorporating floating solids into liquids. 179 8.2 Internal construction of a typical thermocouple. 227
6.11 Side-entry propeller mixers used for blending 8.3 Simple thermocouple circuit. 227
liquids. 180 8.4 Resistance—temperature curve of a thermistor. 229
6.12 Double arm kneader. 182 8.5 (a) Effect of temperature change on a bimetallic
6.13 Helical ribbon impeller. 182 strip. (b) Bimetallic strip thermometer. 230
6.14 Helical coil and anchor mixers. 183 8.6 Vapor pressure thermometer. 231
6.15 Impeller selection. 183 8.7 Vapor pressure curve for methyl chloride. 231
6.16 Tee and injection mixers. 184 8.8 Approximate ranges of thermal conductivities
6.17 An in-line static mixer. 184 of materials at normal temperatures and
6.18 Ribbon blender and a double cone mixer. 187 pressures. 234
6.19 Solids mixer. 188 8.9 Multilayer slab. 235
6.20 Static mixer. 192 8.10 Multilayer hollow cylinder. 236
6.21 Viscosity ranges for different types of mixers. 193 8.11 Multilayer hollow sphere. 236
8.12 Heat transfer shape factors. 236
7.1 Flow patterns in gas–liquid flow in vertical
pipes. 196 9.1 Prandtl numbers of light hydrocarbon gases
7.2 Annular droplet or mist flows. 196 at 1 bar. 246
7.3 Two-phase flow patterns in a vertical 9.2 Hydrodynamic and thermal boundary layers. 247
evaporator tube. 197 9.3 J H factors as function of N Re . 248
7.4 Flow pattern as a function of fraction of air in 9.4 In-line and staggered tube arrangements. 250
air–water flow in a vertical pipe. 197 9.5 Comparison of heat flux for film-type
7.5 Flow patterns in gas/vapor–liquid flows in and dropwise condensation. 251
horizontal pipes. 197 9.6 Condensation on horizontal tube banks. 252
7.6 Stratified and wavy flows. 198 9.7 Film condensation on a vertical plate. 253
7.7 Flow patterns for two-phase flow in horizontal 9.8 Nucleate boiling illustrated. 254
pipes. 199 9.9 Linde porous boiling surface. 254
7.8 Six regimes of fluidization identified with 9.10 Pool boiling curve for water at atmospheric
increasing gas superficial velocities: (a) fixed pressure. 255
bed; (b) particulate fluidization; (c) bubbling 9.11 Stages in pool boiling curve. 256
fluidization; (d) slugging fluidization; 9.12 Bubble agitation. 257
(e) turbulent regime. 201 9.13 Vapor–liquid exchange. 257
7.9 Particle diameter versus gas velocity, showing 9.14 Vaporization. 257
minimum fluidization velocity for good 9.15 Heat transfer mechanisms in convective
fluidization and total carryover bands. 202 boiling in a vertical tube. 259
7.10 Recirculating fluidized bed concept. The draft 9.16 Temperature gradients in forced convection. 260
tube operates as a dilute phase pneumatic 9.17 Overall coefficients. Join process side duty
transport tube. 204 to service side and read U from center scale
7.11 Pressure drop in a fluid–solid bed as a (see dotted line for illustration). 262
function of fluid superficial velocity. 205 9.18 Dowtherm and Syltherm heat transfer fluids. 264
7.12 Typical fluid bed catalytic cracking unit. 206 9.19 Dowtherm, Dowfrost, and Dowcal heat
7.13 Fluid catalytic cracking unit with a two-stage transfer fluids. 264
regenerator (UOP). 207 9.20 Condenser vacuum deaerator for power plant
7.14 Pneumatic conveyance: negative system. 213 boiler. 268