INFLUENCE OF FIN GEOMETRY ON HEAT TRANSFER IN BOILING OF PURE REFRIGERANTS AND THEIR MIXTURES

摘要

Process-integrated energy efficiency in industrial plants may only be achieved with new innovative concepts for the apparatus and the processes. The main obstacle of their application is the absence of adequate reference data and calculation methods for the design and operation of the apparatus. Therefore, a joint research program has been started recently to develop new equipment and processes for heat integration in industrial cooling systems. In this context, the heat transfer in boiling is investigated on differently finned tubes with pure refrigerants and their mixtures in wide ranges of heat flux and saturation pressure. Some of the results of the heat transfer coefficient show no reduction of the mixture values compared to the pure ones on smooth tubes. On finned or enhanced tubes the results are different; the mixture effect is intensified depending on the fin geometry. The effects are explained by the investigation of the bubble formation and the microstructure of the fin tube and compared to measurements from literature.