| Summary: | 碩士 === 淡江大學 === 化學工程與材料工程學系碩士班 === 100 === Considerable improvement of heat transfer efficiency for power-law fluids in
flat-plate heat exchangers is obtainable by inserting in parallel an impermeable
resistless sheet to divide an open duct into two channels for conducting double-flow
operations. The influence of the power-law index on Nusselt numbers in
double-pass parallel-plate heat exchangers with uniform wall fluxes has been
investigated theoretically and experimentally. The analytical solutions were obtained
using the separation of variables, superposition principle and an orthogonal expansion
technique. The theoretical results of the power-law fluids in the temperature
distribution and Nusselt number are compared with those in an open conduit. The
effects of power-law index, recycle ratio, impermeable-sheet position and recycle
configuration have also been presented graphically. The results show that the good
agreement between the experimental results and theoretical prediction. The smaller
the power-law index is, the greater is the improvement of heat transfer efficiency,
especially for high Graetz number.
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