. Applied thermodynamics for engineers. iled treatments of this thermodynamic method have beengiven by Boulvin, Reeve, Berry, and Golding (2). Some precautions necessary inits practical application are suggested in Arts. 454-458. , IRREVERSIBLE PROCESSES 101 Irreversible Processes 175. Modification of the Entropy Conception. It is of importance to distinguishbetween reversible and irreversible processes in relation to entropy significance of the term reversible, as ap-plied to a path, was discussed in Art. 125. Aprocess is reversible only when it consists of aseries of successive s
. Applied thermodynamics for engineers. iled treatments of this thermodynamic method have beengiven by Boulvin, Reeve, Berry, and Golding (2). Some precautions necessary inits practical application are suggested in Arts. 454-458. , IRREVERSIBLE PROCESSES 101 Irreversible Processes 175. Modification of the Entropy Conception. It is of importance to distinguishbetween reversible and irreversible processes in relation to entropy significance of the term reversible, as ap-plied to a path, was discussed in Art. 125. Aprocess is reversible only when it consists of aseries of successive states of thermal equilib-rium. A series of paths constitute a reversibleprocess only when they form a closed cycle,each path of which is itself reversible. TheCarnot cycle is a perfect example of a reversibleprocess. As an example of an irreversible cycle,let the substance, after isothermal expansion,as in the Carnot cycle, be transferred directlyto the condenser. Heat will be abstracted, andthe pressure may be reduced at constant vol-. i^THERMAL Fig. 56. Art. Cycle. Irreversible ume, as along be. Fig. 56. Then allow it to compress isothermally, as in theCarnot cycle, and finally to be transferred to the source, where the temperatureand pressure increase at constant volume, as along da. This cycle cannot beoperated in the reverse order, for the pressure and temperature cannot be reducedfrom a to d while the substance is in communication with the source, nor increasedfrom c to & while it is in communication with the condenser. 176. Irreversibility in the Porous Plug Experiment. We have seen that in thisinstance of unresisted expansion, the fundamental formula of Art. 12 becomesH =T + I -\-W + V (Art. 127). Knowing H = 0, IF = 0, we may write(7+ I) = — F, or velocity is attained at the expense of the internal, energy. Thevelocity evidences kinetic energy ; mechanical work is made possible ; and we mightexpect an exhibition of such work and a fall of internal energy, and c
Size: 1815px × 1377px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1913
