Includes flow work and enthalpy of streams crossing boundaries.
For a control volume: dE_cv/dt=Q̇-Ẇ+Σṁ_in(h+V²/2+gz)-Σṁ_out(h+V²/2+gz). Steady state sets the left side to zero; mass balance Σṁ_in=Σṁ_out. Transient analysis needed for filling or emptying tanks.
A heater warming 0.1 kg/s water by 20 K needs 8.4 kW.
Flow processes add flow work and carried enthalpy to the energy balance, so control volume analysis is needed for pumps, turbines and heat exchangers.
Includes flow work and enthalpy of streams crossing boundaries.
Flow processes add flow work and carried enthalpy to the energy balance, so control volume analysis is needed for pumps, turbines and heat exchangers.
Heat in, work out, and the enthalpy and kinetic and potential energy carried by mass entering and leaving.
When the properties at each inlet and outlet do not change with time and the mass flow is constant.
Typical applications include writing the energy balance for a steam turbine with inlet and outlet flows, analysing the energy of air passing through a fan and modelling a heat exchanger with two streams in steady flow.
Study "Compressibility factor" first (topic 17 of 105 in Thermodynamics & Fluids). It covers the groundwork this topic builds on.
Specific energy of a stream. Flow work Pv included in h. Uniform-flow approximation.
A heater warming 0.1 kg/s water by 20 K needs 8.4 kW.
The next topic is "Steady-flow devices", which builds directly on this one.
It is classed as Beginner in Thermodynamics & Fluids (topic 18 of 105). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.