Abstract:The most popularly used fin types in compact heat exchangers are the serrated fins, wavy fins, louvered fins and plain fins. Amongst these fin types the serrated fins assume lot of importance due to its enhanced thermo-hydraulic performance. Thermo-hydraulic design of CHEs (Compact heat exchangers) is strongly dependent upon the predicted/measured dimensionless performance (Colburn j factor and Fanning friction vs. Reynolds number) of heat transfer surfaces. This paper describes the numerical analysis to study the heat transfer coefficient and friction factor of Serrated fins in water medium. CFD (Computational fluid dynamics) methodology has been used to develop the single phase water heat transfer coefficient and friction factor correlations for serrated fins using ANSYS Fluent 14.5. The results are compared with previous air-cooled models and experimental results of water. The water cooled CFD analysis results shows that the Prandtl number has a large effect on the Nusselt number of the serrated fin geometry. Finally, the generalized correlations are developed for serrated fins taking all geometrical parameters into account. This numerical estimation can reduce the number of tests/experiments to a minimum for similar applications.

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Tuberculosis (TB) is a global problem inspite the availability of drugs. This state of affairs is due to the limitations of existing drugs including muti-drug resistance and toxicites. As a result, there is a pressing need for new antitubercular medicines to be developed. In the present investigation we designed and synthesized a series of isoxazole clubbed 1-carbothioamido-4,5-dihydro-1H-pyrazoles (16-30) in considerable yeilds (43-78%). Further these compounds were purified by recrystallization and charcterized by spectral techniques-Mass, FT-IR and 1H NMR and then evaluated for their antitubercular activity against Mycobacterium tuberculosis H37Rv strain. Among the tested compounds, the analogues 24 bearing 3,5-dimethoxyphenyl scaffold at the 5th position of 4,5-dihydro-1H-pyrazole ring showed superior activity than isoniazid (MIC = 0.25 µg/mL) with MIC value 0.1 µg/mL whereas the compound 25 containing 2,3,4-trimethoxyphenyl had equal potency as that of isoniazid. Additionally, 24 and 25 were found to be less selective towards the human normal liver cell lines-LO2 in their cytotoxicity assays. Hence, these two compounds are safe and useful lead candidates for the development of novel antitubercular drugs.