Tham khảo tài liệu 'heat and mass transfer modeling and simulation part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Numerical Analysis of Heat and Mass Transfer in a Fin-and-Tube Air Heat Exchanger under Full and Partial Dehumidification Conditions 51 The distributions of these velocities over the physical domain where the half fin length and high are settled to are shown in Fig. 6a and 6b. 2 1 air y 0 -1 -2 -2 -1 0 1 2 x Fig. 6a. Horizontal velocity distribution air Fig. 6b. Vertical velocity distribution 52 Heat and Mass Transfer - Modeling and Simulation As shown in Fig. 6a and 6b the horizontal and vertical velocities fields present an apparent symmetry regarding x and y axes. The horizontal dimensionless velocity at the inlet and outlet tends towards unity is maximal at the upper and lower fin edges and is minimal close to the tube wall as a result of the channel reduction. Likewise the vertical dimensionless velocity is close to zero when going up the inlet and outlet or the upper and lower fin edges and is also minimal near the tube surface. Solving heat and mass transfer equations The heat and mass transfer problem has been solved using an appropriate meshing of the calculation domain and a finite-volume discretization method. Fig. 7 illustrates the fin meshing configuration used. 2 1 0 -1 -2 -2 -1 0 1 2 Fig. 7. Fin meshing with 627 nodes. h r In this work up to 11785 nodes are used in order to take into account the effect of the mesh finesse on the process convergence and results reliability. The deviations on the calculation results of the fin efficiency with the different meshing prove to be less than . The numerical simulation is achieved using MATLAB simulation software. A global calculation algorithm for heat and mass transfer models is developed and presented in Fig. 8. Numerical Analysis of Heat and Mass Transfer in a Fin-and-Tube Air Heat Exchanger under Full and Partial Dehumidification Conditions 53 Calculate the condensate-film .
