Disclaimer: The information on this page has not been checked by an independent person.   Use this information at your own risk.
ROYMECHX clone of ROYMECH

 Introduction The steady flow energy equation relates to open systems working under steady conditions i.e in which conditions do not change with time. The boundary encloses a system through which fluid flows at a constant rate, whilst heat transfer occurs and external work is done all under steady conditions ,that is , the rates of mass flow and energy flow are constant with respect to time. The equation for steady flow ( the steady flow energy equation ) is generally written per unit mass as q = heat transfer across boundary per unit mass w = external work done by system per unit mass z = fluid height v = fluid velocity h = fluid enthalpy ( u (internal energy + pv (pressure.specific volume) Note in the examples below the system control volumes are defined by the red dashed line. Heater.. The steady flow equation as applied to a fluid heater.. Potential energy (z) assumed to be constant.. Kinetic energy changes (1 to 2) assumed to be very small Heater w = 0 therefore q = h2-h1 Turbine ..(Assumed Adiabetic Expansion)..The steady flow equation as applied to a turbine.. Potential energy (z) assumed to be constant.. Kinetic energy changes (1 to 2) assumed to be very small Turbine q = 0 therefore w = h2-h1 Throttling ..(Assumed Adiabetic )...The steady flow equation as applied to a orifice.. Potential energy (z) assumed to be constant.. The higher velocity at orifice section is dissipated in tube downstream of the orifice and therefore the kinetic energies at 1 and 2 are similar Orifice q = w = 0 therefore therefore h1 = h2 Nozzle..(Assumed Adiabetic )...The steady flow equation as applied to smooth nozzle.. Potential energy (z) assumed to be constant.. Kinetic energy changes are assumed to be significant Nozzle q = w = 0 therefore (v22 - v12 ) /2 = (h1 - h2 )