35 KB340 KB33 KB199920252003Andrassy, MladenGalović, AntunŽivić, Marija11 straništevilka:2letnik:49str. 100-110ISSN:0039-2480COBISSID:6198555URN:URN:NBN:SI:doc-4CYHF27GenslAssociation of Mechanical Engineers and Technicians of Slovenia et al.Zveza strojnih inženirjev in tehnikov Slovenije et al.Strojniški vestnikefficiencyentropijapovečevanje entropijeprenosniki toploterešitve analitičnesotoktoplotni menjalnikiučinkovitostEntropijska analiza sotočnih prenosnikov toplote| Entropy analysis of parallel-flow heat exchangers|The entropy generation in a parall-flow recuperative heat exchanger is analyzed in this paper. During the operation of a heat exchanger two sources of entropy generation normally exist: the pressure drop (friction) source and the heat-exchange source. Here, only the heat-exchanger source is considered. The analysis is performed using an analytical mathematical model and the same non-dimensional members, that were introduced into the energy analysis of heat exchangers by Bošnjaković, many years ago. The influence of the individual non-dimensional variables (the operating points of the parallel-flow heat exchanger) on the entropy generation is quantified. The results are presented non-dimensionally in diagrams, which gives them a more universal meaning. Special conditions, i.e. the boundary operating conditions,of the parallel-flow recuperator, which are identical to those for counter-flow and cross-flow exchangers, are also discussedV prispevku obravnavamo povečanje entropije v ločilnih sotočnih prenosnikih toplote. Med delovanjem menjalnika se pojavljata dva vira entropije, vsled padca tlaka zaradi trenja in zaradi prenosa toplote. Obravnavajmo samo prenos toplote. Analiza je opravljena z matematičnim modelom, ki uporablja ista brezrazsežna števila, kakor jih je pred leti uvedel Bošnjaković pri energijski analizi prenosnikov toplote. Ovrednoten je vpliv posameznih brezrazsežnih spremenljivk (delovni pogoji sotočnega prenosnika toplote) na povečanje entropije. Izsledki so prikazani brezrazsežno v diagramih, kar jim daje bolj splošen pomen. Posebej so opisane delovne razmere sotočnega rekuperatorja, ki so povsem enake tudi pri protitočnih in križnih menjalnikihTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za strojništvo