Week 1 – Engineering Agenda Introductions and Photos Why should I care about engineering? Motivation for the DB Exam Dimensions and Unit Conversion Examples Ideal Gas Law Conservation of Mass Examples Newtonian Fluids and Viscosity Laminar and Turbulent Flow Friction/Pressure Loss in Pipe Flow

Why is engineering important in brewing? What Engineering Decisions/Designs are Needed in the Brewing Process?

Some Steps in the Brewing Process Malting Mashing In Mashing Lautering Wort Clarification and Cooling Fermentation Carbonization Pasteurization Packaging Learn the Fundamentals, Apply to Brewing

“Margaret’s Story…” For the candy… who are these people?

General Problem Solving Methodology 1.Principles and Equations 2.Simplify and Identify Properties Needed 3.Get Properties (Tables, Equations, etc.) 4.Solve for Unknown, Calculations 5.Interpret Results a)Are the Results Reasonable? b)What Do they Mean?

Dimension – Quantifiable physical entity Primary - Name them… Secondary - Calculated from primary Unit – Metric used to measure dimension Base – m, kg, s, K, A, mole Derived – From base units (J, N, W) Dimensions or Units? “The temperature is 37 outside.” “Increase the psi’s.” “This low flow toilet will save you 2 gpm (gallons per minute) per day.”

Unit Conversion – Just Multiply by 1.0 Units Example 1 What is the power consumed by a 100 Watt light bulb, in horsepower (1 horsepower = kW)?

Units Example 2 A pressure gauge indicates that the pressure inside of a vessel is 350 psig (or psi gauge). The vessel is rated to 50 bar. Should we run for cover? Units Example 3 A cylindrical tank has a 10 foot diameter and 15 foot height. What volume of fluid will the tank hold in gallons and in hectaliters.

The Ideal Gas Equation PV = mRT PV = NR u T R = R u / M For a closed system (no mass in or out)

Ideal Gas Example A 2 m 3 tank is filled to a pressure of 50 bar using an air compressor. After the tank has been filled, it’s temperature is 75  C. After 24 hours, the tank cools to 15  C. a) Determine the mass of air in the tank. b) Determine the pressure in the tank after it has cooled.

Conservation of Mass Mass entering system - Mass leaving system Mass accumulation in system

Conservation of Mass Rate of mass entering system - Rate of mass leaving system Rate of mass accumulation in system

Conservation of Mass Example gallons of beer is initially held in a tank. Beer flows into the tank at a rate of 2.0 gallons per minute (gpm) an it flows out of the tank at 5.0 gallons per minute. Determine: a.The volume of beer after 45 minutes b.The rate of change of the beer volume c.The time elapsed when the tank is empty d.The total amount of beer that left the tank

Conservation of Mass Example 2 Beer with 19% alcohol by weight is mixed with water to create beer with 4.5% alcohol by weight. If the flow rate of 19% alcohol beer is 40 kg/min, what are the flow rates of 4.5% alcohol beer and water, in kg/min and gal/sec?

Fluid Statics ΔP = ρgh (Also use to convert between pressure and pressure ‘head.’) Fluid Statics Example 1 Determine the pressure at the bottom of a 5 m deep tank of liquid water when the top is vented to the atmosphere. Fluid Statics Example 2 Determine the pressure at the bottom of a 5 m deep tank of air when the top is vented to the atmosphere.

Newtonian Fluids and Viscosity Solid Elastic – Returns to original shape Plastic – Partially returns to original Fluid Linear velocity profile while force is applied Force y Surface Fixed v

Newtonian Fluids and Viscosity Shear - one fluid element sliding faster than another, like deck of cards Newton’s Law for viscosity Shear stress = viscosity x shear rate Many units for viscosity – Pa s, poise or cenitpoise are common Force y v

Newtonian Fluids and Viscosity Dynamic viscosity (order of magnitude, STP) Air Pa.s Water Pa.s Olive Oil 0.1 Pa.s Honey 10 Pa.s

Newtonian Fluids and Viscosity Example Determine the dynamic (  ) and kinematic ( ) viscosities of water and air at 300 and 500 K.

Handling Newtonian Fluids Conservation of Mass (Continuity) inout

Handling Newtonian Fluids Example Steam enters a 2.0” diameter pipe at 10 m/s, 1 bar and 150  C. The pipe expands to a 6.0” diameter and the water exits the system at 20  C. a. Determine the water velocity at the outlet of the pipe. b. Determine the mass flow rate. c. Determine the volumetric flow rate at the inlet and exit of the system.

Reynolds Number Laminar flow - “low” flow rates, viscous forces most significant Turbulent flow - “high” flow rates, inertial forces most significant Re < 2300Laminar 2300 < Re < 5000Transitional Re > 5000Fully Turbulent

Reynolds Number Example Recall the previous example: Steam enters a 2.0” diameter pipe at 10 m/s, 1 bar and 150  C. The pipe expands to a 6.0” diameter and the water exits the system at 20  C. Determine if the flow is laminar, transitional or turbulent in the 2.0” and 6.0” pipes.

Entrance Region and Fully Developed Flow Laminar Flow: Turbulent Flow: LeLe

Entrance Region and Fully Developed Flow Example Recall the previous example: Steam enters a 2.0” diameter pipe at 10 m/s and 150  C. The pipe expands to a 6.0” diameter and the water exits the system at 20  C. Determine the entrance length of the inlet (2.0” diameter) pipe. Determine the entrance length if air instead of water.

Fully Developed Velocity Profiles Integrating to get the volumetric flow rate and average velocity, we get… Laminar Flow: Turbulent Flow: Determine the maximum velocities of fully developed flow through the 2.0” and 6.0” pipes in our ongoing example.

Friction Losses in Pipes found on Moody Chart, HT p. 191 Determine the pressure drops over 25 feet of pipe for the 2.0” and 6.0” pipes in our ongoing example (in in H 2 O, psi, and kPa).