CHEN 304-500 Lecture 1 Chapter 1Fluid Mechanics in Chemical Engineering- The majority of chemical processing operations are carried out either partly or totally in fluid stateo Cost-effectiveo More efficientGeneral Concepts- What is a fluid?o A substance that will deform continuously when it is subject to a tangential or shear force- Solid vs. Fluid Solid can resist a shear force Fluid continuously deforms; flowo Solids are made from atoms or molecules close together in a specific geometryo Gases are made of spread out moleculeso Liquids are formed of spread out molecules but are closer together than in gasesStresses, Pressure, Velocity- Stresses are force per unit area- Perpendicular stress (normal):o Tensile – outward forceo Compressive – inward force- Tangential stress causes deformation, τo Degree of deformation, γo Sheer rate, d γ/dt- Pressure is force per unit area and exerts force from all directions; scalar- Atmospheric pressure: 14.7 psi or 101,325 Pa- Gauge pressure tells how much above atmospheric pressure- Velocity is the rate of change of the position of a fluid particle with time o Has magnitude and directiono Macroscopic: ignore variation with positiono Microscopic: consider variation with positionThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.ov =lengthtime- Volumetric flow rate: Q=vA=volumetime- Mass flow rate: m=ρQ= ρvA- Momentum flow rate: Μ=mv=ρ v2AFluid Properties- Density is the mass of molecules per unit volume; ρ=mvo Liquids are mostly incompressible; ρ constanto Gases are compressible; ρ is a function or pressure or temperature- Three basic property dimensions:o Masso Timeo Length- Bulk density is when the oscillating of a fluid levels out - Bulk density is 5-10 times the molecular diameter- For ideal gases: ρ =n MwV=MwPRT- For non-ideal gases: ρ =n MwV=MwPZ RT- Specific gravity: s=ρρsco The ratio of density to the density of the fluid at a standard condition- Viscosity is a measure of the resistance to flowo The closer the molecules are to the moving surface the higher the velocityo Assumption: no slipoμ=τdvdy- Viscosity of liquids: continuous breaking and reforming of interactions between moleculesoμ a e−bT- Viscosity of gases: random motion and collision are responsible for the