Final Exam | BE 477 - Food Engineering: Fluids, Quizzes of Engineering

Download Final Exam | BE 477 - Food Engineering: Fluids and more Quizzes Engineering in PDF only on Docsity! TERM 1 Shear stress = DEFINITION 1 consistency coeff* shear rate ^dimensionless flow behavior index TERM 2 What types of fluids have yield stresses? DEFINITION 2 Herschel BulkleyBingham Plastic TERM 3 Thixotropic ____ with time DEFINITION 3 thin TERM 4 Rheopectic fluids ____ with time DEFINITION 4 thicken TERM 5 n>1 DEFINITION 5 Shear thickening TERM 6 n=1 DEFINITION 6 Newtonian Fluid TERM 7 What ranges of shear stresses should be tested? DEFINITION 7 Max shear stress and 10% of max(4Q)/(piR^3)*(3n+1)/(4n) TERM 8 When can you no longer use concentric viscometers? DEFINITION 8 Large particles ==> >2mm Phase separation particle setting TERM 9 Examples of Newtonian Fluids? DEFINITION 9 Water, alcohol, soft drinks, biological fluids, honey, alcoholic beverages, liquid oils TERM 10 What is k''? And how do you find it? DEFINITION 10 Mixer Coefficientmu*omega = k"*M TERM 21 "NPSH" DEFINITION 21 Net positive suction headUsed to avoid cavitation problems TERM 22 What SS is used in Food? DEFINITION 22 304 TERM 23 What SS is used in Pharm? DEFINITION 23 316 TERM 24 What grit is a 3A standard DEFINITION 24 150 grit TERM 25 18/8 means what? DEFINITION 25 18% chromium and 8% nickel TERM 26 How to calculate friction? DEFINITION 26 Reynolds number => fanning friction coeff => friction loss coefficient => friction loss TERM 27 How do velocity profiles change with increasing shear thinning? DEFINITION 27 They become more blunt TERM 28 Is a particle faster until laminar or turbulent conditions? DEFINITION 28 Laminar TERM 29 Losses based on water DEFINITION 29 (deltaP/rho)_fluid = (deltaP/rho)_water x (f_fluid)/(f_water) TERM 30 Difference between work and shear work? DEFINITION 30 Work is energy required to move the fluidShear work is energy that exposes the fluid to a shear environment TERM 31 Units of Shear Work DEFINITION 31 J/kg TERM 32 Units of Shear Intensity DEFINITION 32 W/m3 TERM 33 What is the z value? DEFINITION 33 temperature difference required to achieve a log change in D values TERM 34 What is the D value? DEFINITION 34 Time required for a 1 log reduction in the microbial population TERM 35 A small z means ____ to temps DEFINITION 35 sensitive TERM 46 Special case for F? DEFINITION 46 When fluid stays at a constant temp due to phase change TERM 47 Effectiveness = DEFINITION 47 E = actual heat transfer/ maximu possible heat transfer TERM 48 "NTU" DEFINITION 48 Number of heat transfer units TERM 49 NTU = DEFINITION 49 UA/C_min TERM 50 Bubble Tube DEFINITION 50 Sends bubbles through a tube to the bottom of a tank to measure the hydrostatic pressure. The hydrostatic pressure will correlate to elevation TERM 51 Conductivity Measurement DEFINITION 51 Current flows between two electrodes. The presence of food or detergent changes this number TERM 52 Vortex Shedding Meter DEFINITION 52 Used in CIPVolumetric measurementKarman vortex streetFluid hits bluff body and creates vorticies. By counting the vorticies, the flow rate can be determined. TERM 53 Eductor DEFINITION 53 Basically a venturi tubeCauses suctionIt makes sure that all the CIP returns. If it doesn't, it can initiate an air lock on the centrifugal pumps TERM 54 Examples of unhygenic designs DEFINITION 54 square cornerslap weldpoor drainageclosed connection - 1 pipe diameter awaydead spacesanything where food can get caught TERM 55 Magnetic Flow meter DEFINITION 55 Electromagnetic induction Volumetric flow meter voltage induced aswater (a conductor)passes the magnetic field which is proportional to velocity TERM 56 Mass flow meter DEFINITION 56 Not volumeCoriolis EffectA bend in the pipe causes a deflecting force that is proportional to mass flow rate TERM 57 RTD DEFINITION 57 Resistance Thermometer Detectormade from a pure material like platinumTemp = function (resistance) TERM 58 Positive Displacement pumps have ____ shear DEFINITION 58 Low TERM 59 What is the pressure difference between the raw and pasteurized side? DEFINITION 59 1 atm. Pressurized on the pasteurized side so pasteurized milk will leak into the raw side rather than the other way around TERM 60 Timing DEFINITION 60 Determined using the speed of the fastest moving particle TERM 71 Demand DEFINITION 71 Acid TERM 72 Factors of cleaning DEFINITION 72 Detergent conc and type Detergent temp soil type and state material mechanical action TERM 73 RT2 Cold Line DEFINITION 73 3 - rinse and drain Hot alkali wash - 145 F, 68 gpm, ~10 minutes 2 - rinse and drain cool acid/sanitize @ 68 gom Sanitize before use TERM 74 Raw Milk Lines - Cold DEFINITION 74 Pre rinse and drain Alkali wash - 168 F at 52 gpm Post rinse and drain Cool acid/sanitize at 52 gpm Sanitize before use TERM 75 HTST - Hot DEFINITION 75 Warm rinse ~ 10 min Alkali wash - 45 minutes 180-190 degF Warm rinse ~5min Acid wash with super sheen - 15 minutes at 165 F Rinse with cold water Sanitize at 170F before use TERM 76 Surfactant DEFINITION 76 Decrease surface tension of water to increase the wetting ability TERM 77 Sanitizers DEFINITION 77 They are meant for clean surfaces not to clean TERM 78 Sugar is _____ soluble DEFINITION 78 Water TERM 79 Fat is _____ soluble DEFINITION 79 AlkaliNOT WATER SOLUBLE TERM 80 Protein is _____ soluble DEFINITION 80 water is variablealkalislightly acid TERM 81 Mineral is _____ soluble DEFINITION 81 water solubility variablemost are acid soluble TERM 82 Overrun DEFINITION 82 The amount of air added to the ice creamit keeps is fluffy TERM 83 What is the viscosity control loop? DEFINITION 83 If you would like to increase the flowrate or the densityDecrease the pressure which decreases the temperature TERM 84 Purpose of homogenization DEFINITION 84 breaks up the fat globules to prevent cream separation TERM 85 Mechanisms DEFINITION 85 Globule disruption by turbulent eddies Disruption by cavitation and subsuquent implosion of steam bubbles Turbulence, high shear, cavitation