The Aroma
The Conclusion
- There are a ton of different flavors detectible in whiskey, but there are two main classes
- Ethyl alcohol is where you get the burn
- Congeners are the complex oak smells
- Liquid-gas phase transfer facilitates smell transport
- High vapor pressure leads to volatility
- The heat of vaporization is the enthalpy of phase change
- Focus on ethyl alcohol
- Flow is driven by pressure
- As you move upward, mass conservation requires that the flow be accelerated
- The converging geometry creates a favorable pressure gradient
- Density: 789 kg/m^3
- Vapor Pressure: 5.95 kPa
- Heat of Vaporization: 841 kJ/kg
The Assumptions
- Cylindrical Coordinates
- Axis-symmetric
- Fully developed
- No body forces
- Snifter can be represented as a parallelogram
- Ethyl alcohol vapor jet
- Neglect body forces
The Snifter
The Sweet Smell of Whiskey
- The snifter is meant to provide an enhancement for the whiskey aroma
- Heat is transferred from your hand to the whiskey through the glass (no ice!)
- The heat helps to evaporate the whiskey, liberating its aroma
- The snifter glass is shaped like a converging nozzle
- Fun fact: on its side the snifter won't spill
The Solution
The Equations
- Continuity
- Z-Momentum
- Simplification
- Boundary conditions
- Velocity is a function of geometry and pressure
- uMax happens at the centerline
- At the top of the glass, geometry is contributing less to velocity
- Is the pressure contributing enough to drive the flow?
The Photos
The Bernoulli
- Bernoulli shows a different way of looking at velocity
- Mass conservation shows that velocity will in fact accelerate the flow when A2 < A1
- Given the change in area, and the volatility of Ethyl Alcohol, there will be an aromatic free jet
- Well-defined jet visible
- Super-critical dihydrogen oxide used for visualization media