Please enable JavaScript.

Coggle requires JavaScript to display documents.

Thermodynamics : (second law (cycles (Heat Engine Thermal Efficiencies …

- - - - Steady Systems
        
        Multiple Inlets/Exits
        
        Single Inlet/Single Exit,
        sesi=\int q/T + sgen
        
        Heat Transfer,
        \int q/T
        Can only calculate if you know how T changes
        through the device or process.
        
        Isothermal,
        \int q/T = q/T
        
        Adiabatic,
        \int q/T=0
        
        Entropy change,
        calculate the same way as closed systems
      - transient system
  - - - Entropy Change, s2s1
        
        Type of process
        
        Cycle, s2s1=0
        
        Process, s2s1~=0
        
        Substance Types
        
        when phase changes,
        use tables
        
        ideal gas,
        (s2s1)=Cp0ln(T2/T1)Rln(P2/P1)
        
        solids and liquids (no phase change),
        s2s1=C*ln(T2/T1)
      - Heat transfer, \int delta Q/T
        
        if adiabatic,
        \int delta Q/T=0
        
        if isothermal,
        \int delta Q/T=Q/Tsystem
      - Entropy Generation, Sgen
        
        if reversible,
        Sgen=0
        
        if irreversible,
        Sgen>0
        
        Also if irreversible....
        (S2S1)=Q/Tsurr + Sgen (universe)
- - - - transient system
      - steady system
        
        multiple inlet/ exit
        
        Single Inlet/Single Exit
        q+h_i+ke_i+pe_i=w+h_e+ke_e+pe_e
        
        Nozzle/Diffuser Throttling Devices/Valves Turbines/Expanders
        Compressors/Fans Pumps Heater/Cooler/Boiler
        Pipes/Ducts
  - - - heat
        
        conduction
        
        convection
        
        radiation
      - work
        
        Boundary Work
        
        When boundary is moving (volume changes through the
        process), W=\int P dV
        
        Isobaric, constant pressure
        P=C
        
        Isothermal (constant temperature) and ideal gas,
        P=mRT/V
        
        Linear,
        P=mV+b
        
        Polytropic,
        P=C/V^n
        
        other
        
        electrical
        
        shaft
        
        chemical
      - TOTAL ENERGY/delta e
        
        potential energy
        
        kinetic energy
        
        internal energy
        
        If ideal Gas
        \Delta u = C_v0*\Delta T
        
        If multi phase (water, refrigerant, or ammonia)
        
        use table
        
        Compressed Liquid
        
        P>Psat
        T<Tsat
        u<uf
        v<vf
        s<sf
        If no compressed liquid table:
        u~uf(at T)
        (ditto for v, s, & h)
        
        Saturated Liquid
        
        P=Psat
        T=Tsat
        u=uf
        (ditto for v, s, & h)
        
        Saturated Mixture
        
        P=Psat
        T=Tsat
        u=uf+x*ufg
        (ditto for v, s, & h)
        
        Saturated Vapor
        
        P=Psat
        T=Tsat
        u=ug
        (ditto for v, s, & h)
        
        Superheated Vapor
        
        P<Psat T>Tsat
        u>ug
        v>vg
        s>sg
        
        If Solid or Liquid (no phase change) \Delta u=C*\Delta T
- - - - One inlet/ one exit
        mdoti=mdote
        M
      - Multiple inlets and exits
        Sum(mi)=Sum(me)