THERMODYNAMIC SYSTEMS AND PROCESSES ThermodynamicsThe theory also states W = 0. Our observations again confirm this to be true as clearly no"work" has been done by the throttling process. Finally, the theory states that an ideal throttlingprocess is adiabatic. This cannot clearly be proven by observation since a "real" throttlingprocess is not ideal and will have some heat transfer.SummaryThe important information from this chapter is summarized below.Thermodynamic Systems and Processes Summary• A thermodynamic system is a collection of matter and space with its boundariesdefined in such a way that the energy transfer across the boundaries can be bestunderstood.• Surroundings are everything not in the system being studied.• Systems are classified into one of three groups:Isolated system - neither mass nor energy can cross theboundariesClosed system - only energy can cross the boundariesOpen system- both mass and energy can cross theboundaries• A control volume is a fixed region of space that is studied as a thermodynamicsystem.• Steady state refers to a condition where the properties at any given point within thesystem are constant over time. Neither mass nor energy are accumulating within thesystem.• A thermodynamic process is the succession of states that a system passes through.Processes can be described by any of the following terms:Cyclic process - a series of processes that results in the systemreturning to its original stateReversible process - a process that can be reversed resulting in no changein the system or surroundingsIrreversible process - a process that, if reversed, would result in a change tothe system or surroundingsAdiabatic process - a process in which there is no heat transfer across thesystem boundariesIsentropic process - a process in which the entropy of the system remainsunchangedPolytropic process - the plot of Log P vs. Log V is a straight line, PVn =constantThrottling process - a process in which enthalpy is constant h1 = h2, work= 0, and which is adiabatic, Q=0.HT-01 Page 30 Rev. 0
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