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Heat Transfer Engineering Applications Part 8

Tham khảo tài liệu 'heat transfer engineering applications part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Thermal Transport in Metallic Porous Media 199 Ja r Cl Ts - Tw 57 The local heat transfer coefficient and Nusselt number along the x direction can be obtained in Eqs. 59 and 60 h i X ke l 1 ke_ơll M Tw - Ts dyv 0 d X Tw - Ts õ y s X y 0- Nu i X h i X X . 59 The condensate film Reynolds number is expressed as follows Re i X Al J x . 60 In the region outside condensation layer the domain extension method is employed where special numerical treatment is implemented during the inner iteration to ensure that velocity and temperature in this extra region are set to be zero and Ts and that these values cannot affect the solution of velocity and temperature field inside condensation layer. The governing equations in Eqs. 52 - 54 are solved with using SIMPLE algorithm Tao 2005 . The convective terms are discritized using the power law scheme. A 200x20 grid system has been checked to gain a grid independent solution. The velocity field is solved ahead of the temperature field and energy balance equation. By coupling Eqs. 52 - 55 the non-linear temperature field can be obtained. The thermal-physical properties in the numerical simulation involving the fluid thermal conductivity fluid viscosity fluid specific heat fluid density fluid saturation temperature fluid latent heat of vaporization and gravity acceleration are presented in Table 4. Parameter Unit Value Liquid density Pl Vapor density Pv Liquid kinematic viscousity Pỵ Liquid thermal conductivity kl Liquid heat capacity at constant pressure cl Saturation temperature Ts Latent heat r Gravity acceleration g kg m-3 977.8 kg m-3 0.58 Pa s 2.825x10-4 W m-1 K-1 0.683 J kg-1 K-1 4200 C 100 J kg-1 297030 -2 m s 9.8 Table 4. Constant parameters in numerical procedure of film condensation 200 Heat Transfer - Engineering Applications For a limited case of porosity being equal to 1 the present numerical model can predict film condensation on the vertical smooth plate for reference case validation. The distribution of film .