Open Systems

So far we have considered closed systems, which do not exchange mass. We now extend the discussion to systems which exchange mass with their surroundings. Additional terms in first and second law account for convective transfer of energy and entropy across system boundaries. In this chapter, we first develop the general equations, and then apply these to standard process elements. Some emphasis lies on evaluation of one-inlet-one-exit systems, such as pumps, compressors, turbines, throttling devices, nozzles and diffusers, including their irreversible losses. The chapter closes with discussions of open and closed heat exchangers, and pressure exchangers.