Tham khảo tài liệu 'heat transfer mathematical modelling numerical methods and information technology part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Optimum Fin Profile under Dry and Wet Surface Conditions 29 optimum fins under the volume constraint is less than the surrounding temperature. A significant change in optimum design variables has been noticed with the design constants such as fin volume and surface conditions. In order to reduce the complexcity of the optimum profile fins under different surface conditions the constraint fin length can be selected suitably with the constraint fin volume. Fig. 9. Variation of temperature and fin profile in a longitudinal fin as a function of length for both volume and length constraints A. Temperature distribution and B. Fin profile 5. Acknowledgement The authors would like to thank King Mongkut s University of Technology Thonburi KMUTT the Thailand Research Fund the Office of Higher Education Commission and the National Research University Project for the financial support. 6. Nomenclatures a constant determined from the conditions of humid air at the fin base and fin tip b slop of a saturation line in the psychometric chart K - 1 C non-dimensional integration constant used in Eq. 84 Cp specific heat of humid air J kg-1 K-1 F functional defined in Eqs. 10 28 46 62 80 and 96 h convective heat transfer coefficient W m 2K1 hm mass transfer coefficient kg m-2 S-1 hfg latent heat of condensation J kg-1 k thermal conductivity of the fin material W m 1 K 1 l fin length m 30 Heat Transfer - Mathematical Modelling Numerical Methods and Information Technology lo wet length in partially wet fins m L dimensionless fin length hl k Lo dimensionless wet length in partially wet fins hl0f k Le Lewis number q heat transfer rate through a fin W Q dimensionless heat transfer rate ri base radius for annular fins m Ri dimensionless base radius hrjk T temperature K U dimensionless fin volume see Eqs. 9 27 45 61 79 91a and 95 V fin volume volume per unit width for longitudinal fins m3 x y coordinates see Figs. 1 and 2 m X Y dimensionless coordinates hx k and hy k respectively yo .
